AU2818995A - Difluorostatone antiviral agents - Google Patents

Description

DIFLUOROSTATONE ANTIVIRAL AGENTS

BACKGROUND OF THE INVENTION

Retroviruses are a class of viruses which transport their genetic material as ribonucleic acid rather than as deoxyribonucleic acid. Retroviruses are associated with a wide variety of diseases in man, one of which is AIDS. Although there have been disclosures of other anti-viral agents useful in the treatment of AIDS, for example see patent applications EP 0 218 688, EP 0 352 000 and PCT/US 91/09741, the compounds of the present invention have not been previously disclosed. PCT/US 91/09741 is hereby incorporated by reference.

SUMMARY OF THE INVENTION

The present invention relates to compounds having the following general formula (I); - O

and the stereoisomers, hydrates, isosteres and the pharmaceutically acceptable salts thereof wherein P₁ i s

wherein T is [(O)_b-W-R] and T' is [(O)_b,-W'-R'] or hydrogen, wherein each of W and W are independently

C_1-6 alkylene or nothing,

provided that W is C_2-6 alkylene when W is directly attached to a nitrogen atom in R,

provided that W' is C_2-6 alkylene when W is directly attached to a nitrogen atom in R', provided that W or W' are each independently C_1-6 alkylene when R or R' are each independently an aryl;

P₂ is C_1-6 alkyl, cyclopentyl, hydroxy C_1-6 alkyl, phenyl, benzyl or 3-tetrahydrofuryl;

R and R' are each independently -CH₂CHO, hydroxy C_1-6 alkyl, C_1-6 alkoxy C_1-6 alkyl, C_1-6 alkyl,

C_1-6 alkenylene, piperazinyl, substituted piperazinyl, piperidyl, morpholinyl, pyridyl, pyrazinyl, pyrimidinyl or phenyl wherein substituted piperazinyl is

piperazinyl substituted on one nitrogen atom thereof with CHO, C(O)NHR'₄, C_1-4 alkyl or CO₂R₄; R₁ is

R₃ is C_1-6 allenyl C_1-6 alkoxy, C_1-6 alkylene, hydroxy C_1-6 alkyl, C_1-6 alkyl or OH;

R₄ is C_1-6 alkyl, phenyl or benzyl;

R'₄ is hydrogen or C_1-6 alkyl; R₅ is hydrogen, C_1-15 alkyl, OH, hydroxy C_1-15 alkyl,

-CH([(CH₂)_d-O-CH₂]_x-R'₈)₂, -CH₂Si(CH₃)₂(R₃), PDL, - ( C_1-6 alkylene)-OR₄, -CH(Y)(Z),

( ) wherein PDL is -(CH₂)_a-2-, 3- or 4-pyridyl, or p- substituted benzyloxy, wherein the substitution is with a nitro, OH, amino, C_1-6 alkoxy, hydroxy C_1-6 alkylene, or halogen; Y is C_1-15 alkyl, hydroxy C_1-15 alkyl, C_1-6 alkyl or -(CH₂)_e-C₆H₄-(V)_e'; Z is -(CH₂)_d-O-CHO, C_1-6 alkylene-O-(CH₂)_d-(O-CH₂-CH₂)_e-O- C_1-6 alkyl, CHO, CO₂R₄ , CO₂NHR₄, -(CH₂)_d-O-(CH₂)_d,-R'₇, -(CH₂)_e-OR₄ or

wherein V is OR₄ or hydroxy C_1-6 alkylene;

provided that d'=2 when R'7 is piperazinyl, substituted piperazinyl, piperidyl or morpholinyl;

R₆ is as defined for R₅ with the proviso that R₆ is other than hydrogen when R₅ is hydrogen, or R₅ and R₆ are taken together with the nitrogen atom to which they are attached are selected from the group consisting of;

R₇ is CH₂OR₄, C(O)NHR₄ or CHO;

R'₇ is piperazinyl, substituted piperazinyl, piperidyl, morpholinyl, pyridyl, pyrazinyl, pyrimidinyl or phenyl, wherein substituted piperazinyl is piperazinyl

substituted on one nitrogen atom thereof with CHO, C(O)NHR₄, C_1-4 alkyl or CO₂R₄;

R₈ is (H, OH) or =O;

R'₈ is pyrimidyl, pyridyl, pyrazinyl or phenyl; a is zero , 1 , 2 or 3 ;

b and b' are each independently zero or 1;

d and d' are each independently 1 or 2;

e and e' are each independently zero, 1 or 2; and x is zero or one.

DETAILED DESCRIPTION OF THE INVENTION

The terms "halo", "halogen" or "halide" refer to a chlorine, bromine or iodine atom.

Isosteres of the compounds of Formula I include those wherein (a) the α-amino acid residues of the P₁ and P₂ substituents are in their unnatural configuration (when there is a natural configuration) or (b) when the normal peptide amide linkage is modified, such as for example, to form -CH₂NH- (reduced), - -N(CH₃) (N-methylamide), -COCH₂-

(keto), -CH(OH)CH₂- (hydroxy), -CH(NH₂)CH₂- (amino),

-CH₂CH₂- (hydrocarbon). Preferably a compound of the invention should not be in an isosteric form. Unless otherwise stated the α-amino acids are preferably in their L-configuration.

A compound of the invention may be in free form, e.g., amphoteric form, or in salt, e.g., acid addition or anionic salt, form. A compound in free form may be converted into a salt form in an art-known manner and vice-versa.

The pharmaceutically acceptable salts of the peptide of Formula I (in the form of water, or oil-soluble or

dispersible products) include the conventional non-toxic salts or the quaternary ammonium salts of these peptides, which are formed, e.g., from inorganic or organic acids or bases. Examples of such acid addition salts include acetate, adipate, alginate, aspartate, benzoate,

benzenesulfonate, bisulfate, butyrate, citrate, camphorate, camphorsulfonate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, fumarate, glucoheptanoate, glycerophosphate, hemisulfate, heptanoate, hexanoate, hydrochloride, hydrobromide, hydroiodide, 2-hydroxyethane- sulfonate, lactate, maleate, methanesulfonate, 2-naphthal- enesulfonate, nicotinate, oxalate, paemoate, pectinate, persulfate, 3-phenylpropionate, picrate, pivalate,

propionate, succinate, tartrate, thiocyanate, tosylate, and undecanoate. Base salts include ammonium salts, alkalimetal salts such as sodium and potassium salts, alkaline earth metal salts such as calcium and magnesium salts, salts with organic bases such as dicyclohexylamine salts, N-methyl- D-glucamine, and salts with amino acids such as arginine, lysine, and so forth. Also, the basic nitrogen-containing groups may be quaternized with such agents as lower alkyl halides, such as methyl, ethyl, propyl, and butyl chloride, bromides and iodides; dialkyl sulfates like dimethyl, diethyl, dibutyl; and diamyl sulfates, long chain halides such as decyl, lauryl, myristyl and stearyl chlorides, bromides and iodides, aralkyl halides like benzyl and phenethyl bromides and others.

The hydrates of the compounds of Formula I are hydrated compounds having the partial structure

and in their end-use application are generally the active forms. In general, as used herein, the term "alkyl" includes the straight, branched-chain and cyclized manifestations thereof unless otherwise indicated, particularly such moieties as methyl, ethyl, isopropyl, n-butyl, t-butyl, -CH₂-t-butyl, cyclopropyl, n-propyl, pentyl, cyclopentyl, n-hexyl, cyclohexyl and cyclohexylmethyl. The term

"aralkyl", when used, includes those aryl moieties attached to an alkylene bridging moiety, preferably methyl or ethyl.

"Aryl" includes both carbocyclic and hetereocyclic moieties of which phenyl, pyridyl, pyrimidinyl, pyrazinyl, indolyl, indazolyl, furyl and thienyl are of primary interest; these moieties being inclusive of their position isomers such as, for example, 2-, 3-, or 4-pyridyl, 2- or 3-furyl and thienyl, 1-, 2-, or 3-indolyl or the 1- and 3- indazolyl, as well as the dihydro and tetrahydro analogs of the furyl and thienyl moieties. Also included within the term "aryl" are such fused carbocyclic moieties as

pentalenyl, indenyl, naphthalenyl, azulenyl, heptalenyl, acenaphthylenyl, fluorenyl, phenalenyl, phenanthrenyl, anthracenyl, acephenanthrylenyl, aceanthrylenyl,

triphenylenyl, pyrenyl, chrysenyl and naphthacenyl. Also included within the term "aryl" are such other heterocyclic radicals as 2- or 3-benzo[b] thienyl, 2- or 3-naphtho[2,3- bjthienyl, 2- or 3-thianthrenyl, 2H-pyran-3-(or 4- or

5-)yl, 1-isobenzo- furanyl, 2H-chromenyl-3-yl, 2- or 3- phenoxathiinyl, 2- or 3-pyrrolyl, 4- or 3-pyrazolyl,

2-pyrazinyl, 2-pyrimidinyl, 3-pyridazinyl, 2-indolizinyl, 1-isoindolyl, 4H-quinolizin-2-yl, 3-isoquinolyl, 2- quinolyl, 1-phthalazinyl, 1,8-naphthyridinyl, 2- quinoxalinyl, 2-quinazolinyl, 3-cinnolinyl, 2-pteridinyl, 4aH-carbazol-2-yl, 2-carbazolyl, β-carbolin-3-yl,

3-phenanthridinyl, 2-acridinyl, 2-perimidinyl,

1-phenazinyl, 3-isothiazolyl, 2-phenothiazinyl,

3-isoxazolyl, 2-phenoxazinyl, 3-isochromanyl, 7-chromanyl, 2-pyrrolin-3-yl, 2-imidazolidinyl, 2-imidazolin-4-yl,

2-pyrazolidinyl, 3-pyrazolin-3-yl, 2-piperidyl, 2-piperazinyl, 1-indolinyl, 1-isoindolinyl, 3-morpholinyl, benzo[b]isoquinolinyl and benzo[b]furanyl, including the position isomers thereof.

Likewise the term "alkylene" includes straight or branched-chain moieties. Some examples of branched-chain alkylene moieties are ethylethylene, 2-methyltrimethylene, 2,2-dimethyltrimethylene, and so on. For example, C₃ alkylene can mean

All ( C_1-6 ) moieties such as C_1-6 alkyl, C_1-6 allenyl, C_1-6 alkoxy, and hydroxy C_1-6 alkyl, are more preferably C_{1 - 3} moieties (containing 1-3 carbon atoms instead of 1-6 carbon atoms). The fluorenylmethyloxy moiety is that moiety generally called by its abbreviation FMOC, and is the fluorenyl moiety bearing -CH₂O attached to the 9-position of the fluorenyl moiety. Other terms defined herein are piperazinyl or substituted piperazinyl

the substitution (*) occurring only at one nitrogen atom which is not attached to the remainder of the molecule (attachment via a nitrogen atom). The substituents are one of CHO, C(O)NHR₄, C_1-4 alkyl or CO₂R₄.

The term "Bn" refers to a benzyl functionality of the formula; Piper idinyl and morpholinyl both bind to the rest of

molecule via their respective nitrogen atoms while

pyrimidinyl, pyridyl and pyrazinyl bind to the rest

of the molecule anywhere except their respective

nitrogen atoms. More specifically, in the instance wherein P₂ is either C_1-6 alkyl or hydroxy C_1-6 alkyl, such moieties as -C(CH₃)₃, -CH(CH₃)₂, -CH(CH₃) (C₂H₅), -C(OH)(CH₃)₂ and -CH(OH)CH₃ are preferred. The "hydroxy C_1-6 alkyl" moiety is illustrated in one example by -CH₂-OH, the "C_1-6 alkoxy C_1-6 alkyl" moiety, is illustrated in one example by -CH₂-OCH₃, (although in each instance the C_1-6 alkylene may be straight or branched and the hydroxy radical is not limited to the terminal carbon atom of the alkyl moiety).

As it is often quite advantageous to have what is termed an amino protecting group (Pg), the scope of those compounds of Formula I includes those R₁ moieties which, together with their adjacent carbonyl moiety form such groups as acetyl (Ac), succinyl (Sue), benzoyl (Bz), t-butyloxycarbonyl (Boc), benzyloxycarbonyl (CBZ), tosyl (Ts), dansyl (DNS), isovaleryl (Iva), methoxysuccinyl

(MeOSuc), 1-adamantanesulphonyl (AdSO₂), 1-adamantaneacetyl (AdAc), phenylacetyl, t-butylacetyl (Tba), bis[(1- naphthyl)methyl]acetyl (BNMA) and Rz wherein Rz is an aryl group as previously described suitably substituted by 1 to 3 members selected independently from the group consisting of fluoro, chloro, bromo, iodo, trifluoromethyl, hydroxy, alkyl containing from 1 to 6 carbons, alkoxy containing from 1 to 6 carbons, carboxy, alkylcarbonylamino wherein the alkyl group contains 1 to 6 carbons, 5-tetrazolo, and acylsulfonamido (i.e., acylaminosulfonyl and sulfonylamino- carbonyl) containing from 1 to 15 carbons, provided that when the acylsulfonamido contains an aryl, the aryl may be further substituted by a member selected from fluoro, chloro, bromo, iodo and nitro.

Among the classes of amino protecting groups

contemplated are: (1) acyl type protecting groups such as formyl, trifluoroacetyl, phthalyl, p-toluenesulfonyl

(tosyl), benzenesulfonyl, nitrophenylsulfenyl,

tritylsulfenyl, O-nitrophenoxyacetyl, and α-chlorobutyryl; (2) aromatic urethane type protecting groups such as benzyloxycarbonyl and substituted benzyloxycarbonyls such as p-chlorobenzyloxycarbonyl, p-methoxybenzyloxycarbonyl, p-nitrobenzyloxycarbonyl, p-bromobenzyloxycarbonyl,

1-(p-biphenylyl)-1-methylethoxycarbonyl, α-, α-dimethyl- 3,5-dimethoxybenzyloxycarbonyl, and benzhydryloxycarbonyl; (3) aliphatic urethane protecting groups such as tert- butyloxycarbonyl (Boc), diisopropylmethoxycarbonyl, iso- propyloxycarbonyl, ethoxycarbonyl, and allyloxycarbonyl; (4) cycloalkyl urethane type protecting groups such as cyclopentyloxycarbonyl, adamantyloxycarbonyl, and cyclohexyloxycarbonyl; (5) thio urethane type protecting groups such as phenylthiocarbonyl; (6) alkyl type protecting groups such as triphenylmethyl (trityl) and benzyl (Bn); (7) trialkylsilane protecting groups such as trimethylsilane if compatible. The preferred α-amino protecting groups are tert-butyloxycarbonyl (Boc) or benzyloxycarbonyl (CBZ). The use of Boc as an α-amino protecting group for amino acids is described by Bodansky et al. in "The

Practice of Peptide Synthesis", Springer-Verlag, Berlin (1984), p. 20.

The term "stereoisomers" is a general term for all isomers of individuals molecules that differ only in the orientation of their atoms in space. It includes mirror image isomers (enantiomers), geometric ( cis/trans) isomers, and isomers of compounds with more than one chiral center that are not mirror images of one another

(diastereoisomers). For amino-acids, the designations L/D, or R/S can be used as described in IUPAC-IUB Joint

Commission on Biochemichal Nomenclature, Eur. J. Biochem. 138: 9-37 (1984).

In general the compounds of this invention may be prepared using standard chemical reactions analogously known in the art. More specifically, the preparation of compounds of structure (3) is well known in the art and described generally by Schirlin, D. and Van Dorsselaer, V. in PCT/US91/09741 published July 23, 1992 with an

international publication number of WO 92/12123.

The compounds of formula (I) can be prepared as described in Reaction Schemes A, A', A", B, C and D. All the substituents, unless otherwise indicated, are

previously defined. The reagents and starting materials are readily available to one of ordinary skill in the art.

In Scheme A, step (a) the aldehyde of formula (3) is subjected to a condensation reaction under Reformatski conditions with an ester of bromodifluoroacetic acid, preferably the ethyl ester in the presence of zinc and in an anhydrous aprotic solvent, e.g., tetrahydrofuran, ether, dimethoxyethane and the like under a nitrogen or argon inert atmosphere. The reaction is gently heated to about 60°C for about 1-12 hours or ultrasonicated to produce compounds (4).

Alternatively, in Reaction Scheme A step (a), the condensation to produce compounds (4) can be achieved in greater yields and at lower reaction temperatures utilizing the following general method. Under an inert atmosphere, such as nitrogen, the aldehyde (3) is dissolved in a suitable anhydrous organic solvent. Examples of a suitable anhydrous organic solvent are tetrahydrofuran, diethyl ether, t-butyl methyl ether and the like. The solution is cooled to approximately 0°C. To the solution is added about 0.30 equivalents of silver acetate, about 2.1 equivalents of zinc dust, and about 2 equivalents of ethyl

bromodifluoroacetate. About 0.34 equivalents of

diethylaluminum chloride (as a solution in toluene) is added slowly to the reaction keeping the temperature of the reaction below 12°C. The reaction is allowed to stir for 1 to 3 hours at about 0°C and then at room temperature for 4 to 12 hours. The reaction is then cooled to about 10°C and quenched with saturated aqueous ammonium chloride. The compound (4) is then isolated and purified by techniques well known in the art. For example a solution of sodium hydrogen tartrate is added and the reaction is allowed to warm from 10°C to room temperature. The mixture is

filtered, the solids washed with a suitable organic

solvent, such as ethyl acetate and the layers of the filtrate are separated. The aqueous layer is extracted with ethyl acetate, the organic layer and extracts are combined, dried over anhydrous magnesium sulfate, filtered and concentrated. The residue is purified by flash

chromatography on silica gel with a suitable eluent, such as cyclohexane/ethyl acetate to provide the compounds (4).

In Scheme A, step (b) formation of compounds (5) or ( 14 ) may be effected directly or undirectly . In one method, the esters of formula (4) or (13) are de-esterified using a suitable base, such as LiOH, KOH, NaOH and the like, in the presence of water and a partially water miscible solvent (such as tetrahydrofuran, dimethoxyethane, dioxane) at about room temperature. The resulting acid can then be aminated with the appropriate R₅R₆-substituted amine using standard peptide-like coupling conditions. The selection of the appropriate coupling reaction procedure is within the skill of the art. The coupling reaction can be carried out using standard coupling procedures such as the azide method, mixed carbonic acid anhydride (isobutyl

chloroformate) method, carbodiimide

[dicyclohexylcarbodiimide, diisopropylcarbodiimide, or water-soluble carbodiimide, 1-(3-dimethylaminopropyl)-3- ethylcarbodiimide hydrochloride (EDC)] method, active ester (p-nitrophenyl ester, N-hydroxy-succinic imido ester) method, Woodward reagent K method, carbonyldiimidazole method, phosphorus reagents such as BOP-Cl, or oxidation- reduction methods. Some of these methods (especially the carbodiimide method) can be enhanced by adding

hydroxybenzotriazole (HOBT), for example the mixed

anhydride method may be employed, using DCC and

hydroxybenzotriazole at room temperature in solvents such as CH₂Cl₂, tetrahydrofuran or dimethylformamide.

Alternatively the esters (4) or (13) may be directly subjected to a reaction with the appropriate R₅R₆- substituted amine without or with a solvent (tetrahydrofuran) at a temperature of from 0 to 80ºC. Alternatively, an appropriate R₅,R₆-substituted amine that is protected as necessary is dissolved in a suitable organic solvent, such as dichloromethane under an inert atmosphere, such as nitrogen. An equivalent of a 2M solution of trimethylaluminum in toluene is added dropwise to the solution. After approximately 15 minutes this solution is added to approximately 0.3 equivalents of ester (4) or (13) dissolved in a suitable organic solvent, such as dichloromethane. The reaction is allowed to stir for about 15 to 24 hours at about room temperature to 40°C. The product is then isolated using techniques well known in the art. For example cold dilute aqueous hydrochloric acid and ethyl acetate is added. The organic layer is separated and washed with water, brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum to provide the compounds (5) or (14).

In Step (c) compounds (6), (8) or (11) are prepared by removal of the P'₁ protecting group using standard

procedures well known in the art [see T.H. Green,

"Protective Groups in Organic Synthesis", John Wiley and Sons, 1981], such as hydrogenation. The free phenol

functionality is then reacted with an appropriate alkyl halide in an inert solvent (preferably anhydrous dioxane, anhydrous acetone or anhydrous dimethylformamide) in the presence of a base (potassium or cesium carbonate) with or without potassium iodide at room or reflux temperature.

In Step (c₁) compound (13) is prepared by removal of the P'₁ protecting group using standard procedures well known in the art[see T.H. Green, "Protective Groups in Organic Synthesis", John Wiley and Sons, 1981], such as, hydrogenation, POH being the compound obtained. POH being a free phenol.

In Step (C₂) compounds (6), (8) or (11) are prepared from the PoHderivatives (14), (16) or (17) by reaction with an appropriate alkylhalide in an inert solvent, in the presence of a base. For example, the POHderivative is dissolved in a suitable organic solvent, such as acetone. Approximately 1.2 equivalents of a suitable base, such as potassium carbonate, are added followed by addition of approximately 1.15 equivalents of the alkyl halide. A catalytic amount of potassium iodide is then added and the reaction is stirred for 1 to 3 days. The product is isolated and purified by techniques well known in the art, such as extractive methods and recrystallization. For example, the reaction is poured into a suitable solvent mixture, such as ethyl acetate/dilute aqueous sodium chloride and the organic layer is separated. The organic layer is then washed with dilute aqueous potassium

hydroxide, brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum. The residue is purified by recrystallization from a suitable solvent mixture, such as cyclohexane/ethyl acetate to provide compounds (6), (8) or (11).

In Step (d), for the preparation of Compounds (7), (9) and (15), the protecting groups Pg may readily be removed by standard procedures well known in the art [see T.H.

Green, "Protective Groups in Organic Synthesis", John Wiley and Sons, 1981], preferably acid/base hydrolysis (e.g., formic acid at room temperature followed by extraction of the free base after treatment with sodium carbonate).

In Step (e), Compounds (7), (9) or (15) are subjected to a peptide coupling procedure with an appropriately protected acid of the formula R'₁CONHCH(P₂)CO₂H or R'₁CO₂H, using the herein-described procedures (or by any other coupling procedure well known in the art, or as described in European Patent Application, Serial Number 93 401 785.6) to produce compounds (8) and (11) (from compound (7)); (10) and (12) (from compound (9)); and (16) and (17) (from compound (15)). R'₁ is defined as R₁ except for those instances wherein protection of the R₁ group may be required as recognized by one of ordinary skill in the art. For example, a hydroxyl functionality on the alkyl portion of the R₁ group must be protected prior to the oxidation in step (f).

In Step (f), the oxidation of compounds (8) and (11) may be effected by methods well known in the art, such as the Swern oxidation procedure, or with 1,1,1-triacetoxy-1,1 dihydro-1,2-benziodoxol-3(1H)-one to provide compounds of formulas IA and IB.

In general the Swern oxidation [see Synthesis, (1981), 165] is effected by reacting about 2 to 20 equivalents of dimethylsulfoxide (DMSO) with about 1 to 10 equivalents of trifluoroacetic anhydride [(CF₃CO)₂O] or oxalyl chloride [(COCl)₂], said reactants being dissolved in an inert solvent, e.g., methylene chloride (CH₂CI₂), said reaction being under an inert atmosphere (e.g., nitrogen or

equivalently functioning gas) under anhydrous conditions at temperatures of about -70°C to -30°C to form an in situ sulfonium adduct to which is added about 1 equivalent of the appropriate alcohols, i.e., compounds (8) and (11).

Preferably, the alcohols are dissolved in an inert solven , e.g., CH₂CI₂, tetrahydrofuran, or minimum amounts of DMSO, and the reaction mixture is allowed to warm to about -50°C or -20°C (for about 20-60 minutes) and then the reaction is completed by adding about 3 to 30 equivalents of a tertiary amine, e.g., triethylamine, diisopropylethylamine, N-methyl morpholine, etc.

Alternatively the oxidation can be carried out with the Dess-Martin periodinane (i.e., 1,1,1-triacetoxy-1,1- dihydro-1,2-benziodoxol-3(1H)-one), [see Dess Martin, J. Org. Chem., 48, 4155, (1983)]. This oxidation is effected by contacting about 1 equivalent of the alcohol with 1 to 10 equivalents of periodinane (preferably greater than 5 equivalents), said reagent being in suspension in an inert solvent (e.g., methylene chloride) under an inert

atmosphere (preferably nitrogen) under anhydrous conditions at 0°C to 50°C (preferably room temperature) and allowing the reactants to interact for about 1 to 48 hours.

Optional deprotection of the amine protecting groups may be effected as desired after the ketones have been isolated.

In general, the modified Jones oxidation procedure may conveniently be effected by reacting the alcohols with pyridinium dichromate by contacting the reactants together in a water-trapping molecular sieve powder, e.g., a

grounded 3 Angstrom molecular sieve), wherein said contact is in the presence of glacial acetic acid at about 0°C to 50°C, preferably at room temperature followed by isolation and then optionally removing amine protecting groups.

Alternatively, 1 to 5 equivalents of a chromic

anhydride-pyridine complex (i.e., a Sarett reagent prepared in situ ) [see Fieser and Fieser "Reagents for Organic

Synthesis" Vol. 1, pp. 145 and Sarett, et al., J.A.C.S. 25, 422, (1953)] in an inert solvent (e.g., CH₂CI₂) under an inert atmosphere under anhydrous conditions at 0°C to 50°C is treated with 1 equivalent of the alcohol. The reaction is allowed to stir for about 1 to 15 hours. The product is isolated and purified by techniques well known in the art followed by optionally removing amine protecting groups.

In step (g) the compounds decribed by formulas IA and IB wherein R'₁ is protected as required, are deprotected under conditions well known in the art [see T.H. Green, "Protective Groups in Organic Synthesis", John Wiley and Sons, 1981], to provide compounds of formula IA' and IB' wherein R"₁ are those substituents which required

protection as required. For example the protected compound is dissolved in a suitable organic solvent, such as

methylene chloride and treated with TFA/H₂O. The reaction is allowed to stir at room temperature for about 4 to 10 hours and then it is concentrated under vacuum. The residue is purified by techniques well known in the art, such as extractive methods followed by flash chromatography (silica gel, hexane/ethyl acetate) to provide the

deprotected compound.

For the preparation of the necessary aldehydes of formula (3) and the acids which are to be coupled with the compounds (7), (9) or (15), alternative alkylation

procedures are utilized depending upon whether the P₁ and/or the P₂ moieties are or are not residues of natural amino acids. For the preparation of these intermediates wherein the P₁ or P₂ moieties are residues of natural amino acids (or minor modifications thereof, e.g., P₁ or P₂ being a benzyl or methyl ether of tyrosine), the compounds are either known or are prepared by processes and techniques well known in the art. To prepare the intermediates of the formula

P₃

wherein Pg is an amino protecting group, P₃ is either a P ' ₁ or P'₂ moiety with P'₁ and P'₂ being as defined for P₁ and P₂ respectively, except that they are other than residues of naturally occuring amino acids, and the R₉ moiety is an alkyl radical, preferably methyl when P₃ is P'₁, and ethyl when P₃ is P'₂, alternative methods are available.

To prepare the intermediates of formula P'_{1 2}

the following reaction scheme may be utilized

REACTION SCHEME B

PgNHCH₂CO₂R₉

(18) wherein P₃ is as previously defined and X is a leaving group, preferably halo or triflate, R₉ is methyl when P₃ is P'₁, and ethyl when P₃ is P'₂.

In essence, the preparation of compounds (19) utilizes the Krapcho method [Tetrahedron Letters, 2.6, 2205 (1976)] for alkylation wherein compounds (18) are treated with a base, e.g., LDA, (lithium diisopropylamide), followed by reaction with the desired P₃X in the presence of TMEDA (i.e. tetramethylethylenediamine) in a solvent (tetrahydrofuran) with or without HMPA (i.e. hepamethylphosphonamide) according to the standard Krapcho conditions. Following alkylation the compounds are then subjected to a reduction using diisobutyl alaminum hydride (Dibal) in a mixture of solvents, e.g., ether, toluene, hexane, tetrahydrofuran at about -78°C for about 1 hour. Following the preparation of the aldehydes of Formula (10B), the compounds are subjected to the processes of Reaction Schemes A, A' and/or A".

Alternatively, the compounds of (19) may be prepared by a Malonate/Curtius type sequence of reactions, [see Yamada, et al., J. Amer. Chem. Soc, (1972) 94, 6203] as illustrated by the following reaction scheme REACTION SCHEME C

t-BuO₂CCH₂CO₂R₉

( 20 )

pe ent

wherein t-Bu is t-butyl, although other selectively removable acid protecting groups may be utilized, and P₃X is as previously defined. This reaction involves the alkylation of the malonate ester (20) followed by selective removal of the t-butyl protecting group to produce

compounds (22). These compounds are then transformed to (19) using the Curtius type rearrangement which entails their conversion to the protected amine via the

intermediately formed acylazides and isocyanates. The resultant amines are then protected with standard amino protecting groups, preferentially being protected in situ .

In the instance wherein P₃ represents a P'₁ moiety, the ester is transformed to the desired aldehydes of

Formula (3) using standard Dibal reduction techniques, particularly in this situation (wherein P₁ is not a residue of a natural amino acid). Alternatively, (as is preferred when P₁ is a residue of a natural amino acid) the ester is de-esterified to its corresponding acid, converted to its corresponding hydroxamate and the hydroxamate upon

treatment with lithium aluminum hydride is converted to its aldehyde. In the instance wherein P₃ represents a P'₂ moiety, the ethyl ester of compounds (19) are removed and the resulting compounds are ready for coupling as outlined in Reaction Scheme A'. In Scheme D an alternative procedure for preparation of compounds of formula IA is set forth.

Reaction Scheme D

(7)

P₁

- -

- O

- - O O O

In Scheme D, step (a) compounds of formula (7) are subjected to a coupling reaction in a manner analogous to that described previously in Scheme A' step (e) with a suitably protected acid of the formula PgNHCH(P₂)CO₂H to provide compound of formula (23).

In Scheme D, step (b) compounds of formula (23) are deprotected in a manner analogous to that described in Scheme A, step (d) to provide compounds of formula (24). In Scheme D, steps (c) and (d) compounds of formula (24) are first subjected to a coupling reaction with an acid of the formula R'₁CO₂H in a manner analogous to that described in Scheme A' step (e) and the coupled product is then oxidized in a manner analogous to that described in Scheme A' step (f) to provide the compounds of formula IA.

It is understood by one of ordinary skill in the art that compounds of formulas (9) and (15) may be manipulated in a manner analogous to formula (7) in Scheme D, in addition to the manipulations decribed in Schemes A' and A" to provide compounds of formulas IA, IA', IB and IB'. Having generically described the methods for the preparation of the compounds of this invention, the

following specific examples illustrate the chemistry and techniques by which the synthesis may be effected. The following examples present typical syntheses as described in Schemes A, A', A" and D. These examples are understood to be illustrative only and are not intended to limit the scope of the present invention in any way. As used herein, the following terms have the indicated

meanings: "g" refers to grams; "mmol" refers to millimoles; "ml" refers to milliliters; "bp" refers to boiling point; "mp" refers to melting point; " ºC" refers to degrees

Celsius; "mm Hg" refers to millimeters of mercury; "μL" refers to microliters; "μg" refers to micrograms; "μM" refers to micromolar; "Cbz" means carbobenzyloxy; "DMF" means dimethylformamide; "THF" means tetrahydrofuran;

"TBAF" means tetrabutylammonium fluoride; "NMM" means N- methylmorpholine; "DMSO" means dimethylsulfoxide; "HOBT" means hydroxybenzotriazole and "EDC" means 1-(3- dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride. Example 1

Preparation of α,α-Difluoro-γ-[[(2-(R)-

[[(hydroxy)phenylacetyl]amino]-3-methyl-1-oxobutyl]amino]- B-oxo-4-(phenylmethoxy)-N-(phenylmethyl)-benzene- pentanamide.

Step A

Preparation of O-benzyl-N-(tert-butoxycarbonyl)-L- tyrosinal; the starting material in Reaction Scheme A, .

[Following the procedure of Schirlin, D. and Van

Dorsselaer, V. in PCT/US91/09741 published July 23, 1992 with an international publication number of WO 92/12123.] A mixture of N-tert-butoxycarbonyl-L-O-benzyltyrosine (37.1 g, 100 mmol), dicyclohexylcarbodiimide (20.6 g, 100 mmol), and N-hydroxybenzotriazole hydrate (15.3 g, 100 mmol) in anhydrous dichloromethane (350 mL) is stirred at 0°C for 10 minutes. To this is added at 0°C, N,O- dimethylhydroxylamine hydrochloride ( 9.75 g , 100 mmol) and N-methylmorpholine (10.1 g, 100 mmol). The temperature is allowed to warm to room temperature and stirring is continued for 15 hours. The white precipitate is then filtered off and rinsed with dichloromethane. The filtrate is concentrated under vacuum and the residue is purified by flash chromatography (silica gel, ethyl

acetate/cyclohexane, 2:8) to provide the N-tert- butoxycarbonyl-L-O-benzyltyrosine-N,On-dimethyl-hydroxamate (34.3 g) as a white solid (R_F=0.36 in ethyl

acetate/cyclohexane, 1:1). The N-tert-butoxycarbonyl-L-O-benzyltyrosine-N,O- dimethyl-hydroxamate (18.2 g, 44 mmol) is dissolved in a mixture of anhydrous diethyl ether/dimethoxyethane (300 mL, 4:1) and cooled to 0°C. To this is added lithium aluminum hydride (1.82 g, 48 mmol) portionwise. The reaction is stirred at 0°C for 1.5 hours. A 1M solution of potassium hydrogen sulfate (55 mL) is then added dropwise with stirring to the reaction. After addition is complete, the aqueous phase is decanted and extracted with ethyl acetate (2 x 200 mL). The combined organic layers are washed with 3N hydrochloric acid (250 mL), water (200 mL), saturated sodium bicarbonate (150 mL) and brine (200 mL). The organic layer is then dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum. The residue is recrystallized from ethyl acetate/pentane to provide N-tert-butoxycarbonyl-L-O-benzyltyrosinal (13 g).

Step B

Preparation of 4-tert-butoxycarbonylamino-2,2-difluoro-3- hydroxy-5-(4-benzyloxy)phenylpentanoic acid, ethyl ester.

Reaction Scheme A, step (a); To a stirred mixture of N-tert-butoxycarbonyl-L-O-benzyltyrosinal (13.0 g, 36.6 mmol), silver acetate (1.82 g, 10.9 mmol), activated zinc dust (5.02 g, 76.8 mg-atom, washed with 3N hydrochloric acid, water, acetone and ether) and ethyl

bromodifluoroacetate (14.8 g, 72.9 mmol) in anhydrous tetrahydrofuran (120 mL) at 0°C is added diethylaluminum chloride (22.4 mL of a 1.8M solution in toluene) over 20 minutes. The temperature is kept below 12°C during the addition. The reaction is then allowed to stir at 0°C for 90 minutes and then at room temperature for 4 hours. The reaction is then cooled to 10°C and quenched with saturated aqueous ammonium chloride (200 mL). A 1M solution of sodium hydrogen tartrate (200 mL) is added and the reaction is allowed to warm to room temperature. The reaction is filtered and the solids rinsed with ethyl acetate. The filtrate layers are separated and the aqueous layer is extracted with ethyl acetate. The combined organic layers are dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum. The residue is purified by flash chromatography (cyclohexane/ethyl acetate, 4:1) to provide the title compound (8.34 g). The ratio of

diastereomers is approximately 1:1.

Step C

Preparation of 4-tert-Butoxycarbonylamino-2,2-difluoro-3- hydroxy-5-(4-benzyloxy)phenyl-N-(phenylmethyl)pentanamide.

Reaction Scheme A step (b): To a solution of 4-tert- butoxycarbonylamino-2,2-difluoro-3-hydroxy-5-(4- benzyloxy)phenylpentanoic acid, ethyl ester (5.5 g, 11.5 mmol) in anhydrous tetrahydrofuran (50 mL) is added at 0°C, benzylamine (6.15 g, 57.5 mmol). The reaction is stirred for 3 hours at 0°C, then at room temperature for 15 hours . The reaction is then diluted with ethyl acetate (100 mL), washed with 0.1N aqueous hydrochloric acid (2 x 50 mL), water (50 mL), brine (50 mL) and dried over anhydrous magnesium sulfate. It is then filtered and concentrated under vacuum. The residue is recrystallized from ethyl acetate/pentane to provide the title compound (5.17 g) as a white solid. Step D

Preparation of 4-amino-2,2-difluoro-3-hydroxy-5-(4- benzyloxy)phenyl-N-(phenylmethyl)pentanamide.

Reaction Scheme A, step (d): A solution of 4-tert- butoxycarbonylamino-2,2-difluoro-3-hydroxy-5-(4- benzyloxy)phenyl-N-(phenylmethyl)pentamide (5.1 g, 9.4 mmol) in trifluoroacetic acid (100 mL) is stirred at 0°C for 1 hour. The solvent is then removed under vacuum and the residue dissolved in ethyl acetate (100 mL). The organic layer solution is washed with saturated sodium bicarbonate (3 x 50 mL), brine, dried over anhydrous magnesium sulfate, filtered and concentrate under vacuum to provide the title compound as a white solid; R_f=0.62 (silica gel,

butanol/acetic acid/water, 6:2:2).

Step E

Preparation of N-(R)-[[[(1,1-

Dimethylethyl)dimethylsilyl]oxy]phenylacetyl]-L-valine.

To a stirred solution of (R)-(-)-mandelic acid (5.6g, 37 mmol) and tert-butylchlorodimethylsilane (15.0 g, 99.5 mmol) in DMF (100 mL) is added imidazole (16.7 g, 245 mmol) in portions over 15 minutes while maintaining the reaction mixture near 25°C with a cool water bath. After 17 hours, the mixture is diluted with water and extracted with two portions of ether. The combined extracts are cooled to - 10°C and washed quickly with cold (-10°C) 1 N HCl, twice with cold water, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum to provide 15.0 g of a yellow oil which is then dissolved in CH₃OH (250 mL) and THF (80 mL). A solution of potassium carbonate (14 g, 100 mmol) in water (140 mL) is added with vigorous stirring. After 1 hour, the mixture is partially concentrated under vacuum and the remaining clear light yellow solution is diluted with brine (300 mL). The cloudy mixture is cooled to -10°C and acidified to pH 5 with 1 M KHSO₄. Extraction with cold (-10°C) ether and washing of the extracts with two portions of brine provides, after drying with anhydrous sodium sulfate, filtration and concentration under vacuum, 6.6 g (67%) of (R)-O-tert-butyldimethyl-silylmandelic acid as a yellow oil. This crude silylated acid (25 mmol) is dissolved in CH₃CN (80 mL) and the resulting solution is cooled to -10°C. To the stirred solution is added NMM (2.52 g, 24.9 mmol), then isobutylchloroformate (3.72 g, 27.2 mmol). After 10 minutes, a solution of L-valine methyl ester hydrochloride (7.32 g, 43.7 mmol) and NMM (4.08 g, 40.3 mmol) in H₂O (20 mL) is added and stirring is continued at -10°C for 20 minutes. The reaction mixture is poured into ice-cold dilute HCl containing some NaCl and extracted with two portions of ethyl acetate. The combined extracts are washed with water, aqueous saturated sodium

bicarbonate, brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum. Two flash

chromatographies (12% ethyl acetate in cyclohexane) provide 4.4 g of coupled silylated ester (R_f 0.4, 4/1

cyclohexane/ethyl acetate) contaminated with N- isobutyloxycarbonyl-L-valine methyl ester. The silylated ester (4.4 g, 12 mmol) is dissolved in THF (15 mL) with stirring and a solution of 1 M tetrabutylammonium fluoride (TBAF) in THF (11.6 mL) is added. After 1.25 hours, the solution is concentrated under vacuum and the residue is purified by flash chromatography (4/1 cyclohexane/ethyl acetate) to provide 2.4 g (37% overall from O-tert- butyldimethylsilylmandelic acid) of N-[(R)-mandeloyl]-L- valine methyl ester as an oil. Following the procedures in a manner analogous to that described above, the material is reconverted to its O-tert-butyldimethylsilyl ether in 82% yield after flash chromatography (12% ethyl acetate in cyclohexane). To a stirred solution of this ester (13.5 mmol) in CH₃OH (125 mL) and water (5 mL) is added LiOH•H₂O (0.59 g, 14 mmol). After 17 hours an additional amount of LiOH•H₂O (0.06 g) is added and stirring is continued for 2 hours. The solution is concentrated under vacuum and the residue is diluted with water (100 mL) and washed with ether. The aqueous layer is acidified with ice-cold 6 N HCl and extracted with two portions of ether. The combine extracts are washed with water, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum to provide the title compound in 48% yield as a white solid: mp 146-148°C; IR (CHCl₃) ν_max 2957, 2932, 1718,

1678, 1516, 1096, 863, 840 cm^-1; ¹H NMR (CDCI₃) δ 9.17 (bs, 1 H), 7.51 (d, 1 H, J=9.0 Hz), 7.43-7.40 (m, 2 H), 7.32- 7.25 (m, 3 H), 5.15 (s, 1 H), 4.51 (dd, 1 H, J=9.0, 4.3 Hz), 2.34-2.28 (m, 1 H), 1.00 (d, 3 H, J=6.9 Hz), 0.97 (d, 3 H, J=7.0 Hz), 0.94 (s, 9 H), 0.11 (s, 3 H), -0.08 (s, 3 H); ¹³C NMR (CDCI₃) δ 175.49, 172.65, 139.36, 128.32,

128.21, 126.68, 75.66, 56.60, 31.04, 25.66, 19.01, 18.02, 17.44, -4.83, -5.31; mass spectrum, m/z 394 (M⁺ + 29), 366 (M⁺ + 1, 100), 350, 308; exact mass calcd for C₁₉H₃₂NO₄Si 366.2101, found 366.2099; [α]²⁰ _D -56.6° (c 1.00, CH₃OH). Anal. Calcd for C₁₉H₃₁NO₄Si: C 62.43; H, 8.55; N, 3.83. Found: C, 62.22; H, 8.61; N, 3.65.

Step F

Preparation of [3ξ,4(S,R)]-2,4,5-Trideoxy-4-[[2-[[[[(1,1- dimethylethyl)dimethylsilyl]oxy]phenylacetyl]amino]-3- methyl-1-oxobutyl]amino]-2,2-difluoro-5-[4-

(phenylmethoxy)phenyl]-N-(phenylmethyl)-L-glycero- pentanamide.

Reaction Scheme A', step (e): N-(R)-[[[(1,1- dimethylethyl)dimethylsilyl]oxy]phenylacetyl]-L-valine prepared above (25 mmol) is dissolved in CH₃CN (80mL) and the resulting solution cooled to -10°C. To the stirred solution is added N-methylmorpholine (2.52 g, 24.9 mmol, NMM), followed by isobutylchloroformate (3.72 g, 27.2 mmol). After 10 minutes, a solution of 4-amino-2,2- difluoro-3-hydroxy-5-(4-benzyloxy)phenyl-N-(phenylmethyl) pentanamide (43.7 mmol, prepared in step (d) above) and NMM (4.08 g, 40.3 mmol) in H₂O (20 mL) is added and stirring is continued at -10°C for 20 minutes. The reaction mixture is poured into ice-cold dilute HCl containing some NaCl and is extracted with two portions of ethyl acetate. The combined extracts are washed with water, aqueous saturated sodium bicarbonate, brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum. The title compound is obtained in 76% yield as a clear colorless oil which crystallizes on standing after flash chromatography (6% acetone in CH₂Cl₂): mp 117-120°C; IR (KBr) v_max 3418, 1704, 1677, 1653, 1540, 1513, 1246, 1095, 839 cm^-1; ¹H NMR (CDCI₃) δ 7.44-7.18 (m, 16 H), 6.96 (d, 3 H, J=8.7 Hz), 6.84 (d, 2 H, J=8.7 Hz), 6.10 (d, 1 H, J=8.1 Hz), 5.10 (s, 1 H), 5.01 (s, 2 H), 4.69 (d, 1 H, J=6.9 Hz), 4.43 (dd, 1 H, J=14.7, 6.0 Hz), 4.34 (dd, 1 H, J=14.7, 6.0 Hz), 3.96 (dd, 1 H, J=8.5, 6.9 Hz), 3.91-3.82 (m, 2 H), 2.76 (dd, 1 H, J=13.8, 7.8 Hz), 2.66 (dd, 1 H, J=13.8, 7.8 Hz), 2.22-2.11 (m, 1 H), 0.94 (s, 9 H), 0.88 (d, 3 H, J=6.6 Hz), 0.86 (d, 3 H, J=6.9 Hz), 0.09 (s, 3 H), -0.06 (s, 3 H); ¹³C NMR (CDCI₃) δ 173.37, 171.91, 163.92 (t, J=35 Hz), 159.01, 139.62,

137.40, 137.31, 130.47, 129.60, 129.16, 128.94, 128.80, 128.70, 128.37, 128.31, 128.22, 127.83, 126.63, 115.50 (t, J=257 Hz), 115.36, 76.21, 70.67 (t, J=25 Hz), 70.37, 58.79, 51.93, 43.76, 36.52, 29.97, 26.08, 19.80, 18.47, 17.96, - 4.41, -4.89; ¹⁹F NMR (CDCI3) δ -118.40 (s), -118.45 (s); mass spectrum, m/z 816 (M⁺ + 29), 788 (M⁺ + 1), 573, 469,

441, 423 (100); exact mass calcd for C₄₄H₅₆F₂N₃O₆Si 788.3906 found 788.3932; [α]²⁰ _D -74.6° (c 1.02, CH₃OH). Anal. Calcd for C₄₄H₅₅F₂N₃O₆Si: C, 67.06; H, 7.04; N, 5.33. Found: C, 67.07; H, 7.14; N, 5.18.

Step G

Preparation of final title compound.

Reaction Scheme A', steps (f) and (g): The above prepared alcohol is oxidized under Swern conditions as follows: To a stirred solution of 2 M oxalyl chloride/CH₂Cl (2.0mL) at -60°C under nitrogen is added dropwise anhydrous DMSO (0.42 mL, 5.9 mmol). After 10 minutes, a solution of [3ξ,4(S,R)]-2,4,5-Trideoxy-4-[[2-[[[[(1-1- dimethylethyl)dimethylsilyl]oxy]phenylacetyl]amino]-3- methyl-1-oxobutyl]amino]-2,2-difluoro-5-[4-

(phenylmethoxy)phenyl]-N-(phenylmethyl)-L-glycero- pentonamide (0.50 mmol) in CH₂CI₂ (3 mL) and anhydrous DMSO (1.5 mL) is added. The solution is allowed to stir at -65 to -55°C for 5 hours. It is then warmed to -20°C, followed by addition of triethylamine (1.39 mL, 10.0 mmol) over 5 minutes. The reaction mixture is then allowed to warm to room temperature overnight. It is then diluted with ethyl acetate (60 mL) and filtered, washing the solids with ethyl acetate. The filtrate is washed with 0.1 M HCl (3 x 15 mL), brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum to provide 375 mg of crude ketone. This is dissolved in 4/1 acetic acid/H₂O (50 mL). The stirred solution is heated at 80°C for 19 hours, allowed to cool to room temperature before being diluted with water and extracted with two portions of CH₂CI₂. The combined extracts are washed with water, brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum. Flash chromatography of the residue (10% acetone in CH₂CI₂) provides 180 mg title compound

contaminated by residual silylated compound. The material is resubjected to the reaction conditions and purified by flash chromatography to provide 121 mg of final title compound. Two recrystallizations from ethyl

acetate/pentane provide 30 mg (8.8%) of final title

compound as a pale yellow solid: mp 144-150°C; IR (KBr) v_max 3398, 3300, 1683, 1656, 1540, 1513, 1454, 1244, 698 cm^-1; ¹H NMR (DMSO-d₆) δ 9.77-9.72 (m, 1 H), 8.69 (d, 1 H, J=7.6 Hz), 7.80 and 7.73 (2d, 1 H total, J=9.3 Hz), 7.45-7.21 (m, 15 H), 7.12 and 7.10 (2d, 2 H total, J=8.7 Hz), 6.89 and 6.87 (2d, 2 H total, J=8.8, 8.4 Hz), 6.21 and 6.20 (2d, 1 H total, J=5.1 Hz), 5.05 (s, 2 H), 5.02 and 5.00 (2s, 1 H total), 5.03-4.90 (m, 1 H), 4.38 (d, 2 H, J=5.7 Hz), 4.23- 4.17 (m, 1 H), 3.14-3.07 and 2.65-2.57 (m, 2 H total), 1.97-1.88 and 1.78-1.73 (m, 1 H total), 0.73 and 0.71 (2d, 3 H total, J=6.7 Hz), 0.57 and 0.49 (2d, 3 H total, J=6.9, 6.7 Hz); ¹⁹F NMR (DMSO-d₆) δ -110.31 (d, J=268 Hz), -110.54 (d, J=268 Hz), -112.21 (d, J=268 Hz), -112.25 (d, J=269 Hz); mass spectrum, m/z 700 (M⁺ + 29), 672 (M⁺ + 1, 100), 652, 439, 421, 402; exact mass calcd for C₃₈H₄₀F₂N₃O₆

672.2885, found 672.2842.

Example 2

Preparation of [6S-(6R*, 9R*, 13S*)]-4,4,-Difluoro-9-(1- methylethyl)-3,5,8,11-tetraoxo-1,13-diphenyl-6-[[4- (phenylmethoxy)phenyl]methyl]-12-oxa-2,7,10- triazatetradecan-14-oic Acid, Methyl Ester.

Step A

Preparation of [3ξ,4(S)]-2,4,5-Trideoxy-4-[[2-[[(1,1- dimethylethoxy)carbonyl]amino]-3-methyl-1-oxobutyl]amino-

[4-(phenylmethoxy)phenyl]-N-(phenylmethyl)-L-glycero- pentanamide.

Reaction Scheme D, step (a): To an ice-cold stirred solution of 4-amino-2,2-difluoro-3-hydroxy-5-(4- benzyloxy)phenyl-N-(phenylmethyl)pentanamide (556 mg, 1.23 mmol, prepared in example 1, step D) in 2:1 dry CH₂CI₂/DMF (13.5 mL) is added HOBT (0.19 g, 1.2 mmol), DCC (0.26g, 1.3 mmol) and N-t-Boc-L-valine (0.27 g, 1.2 mmol). The reaction mixture is allowed to warm to 25°C overnight, then diluted with ethyl acetate/cyclohexane, washed with dilute aqueous sodium bicarbonate, water, brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum to provide a gummy solid. This is triturated with CH₂CI₂ and filtered to remove some of the

dicyclohexylurea. The filtrate is concentrated under vacuum and the residue is purified by flash chromatography (3:2 cyclohexane/ethyl acetate) to provide 694 mg (88%) of the title compound as an ivory solid. The major

diastereomer is separated in 69% yield by recrystallization from ether/CH₂Cl₂. Step B

Preparation of the chloroformate of formula:

To a stirred solution of triphosgene (6.65 g, 22.4 mmol) in CH₂CI₂ (25 mL) under nitrogen is added (R)-(-)- methyl mandelate (5.36 g, 32.3 mmol) followed by the rapid addition of a solution of pyridine (2.66 mL, 32.9 mmol) in- CH₂CI₂ (2.5 mL). The reaction mixture is warmed to reflux and pyridinium chloride separated. After 17 hours at room temperature, the reaction mixture is partially concentrated under vacuum, diluted with ethyl acetate, and filtered.

The filtrate is concentrated concentrated under vacuum and the residue is again dissolved in ethyl acetate and

filtered. Concentration under vacuum provides 7.25 g of a pale yellow oil composed of approximately a 20:1:1 mixture of chloroformate: carbonate: methyl mandelate. For the chloroformate IR (neat) v_max 1772, 1750 cm^-1; ¹H NMR (CDCI₃) δ 7.5-7.37 (m, 5 H), 5.98 (s, 1 H), 3.78 (s, 3 H).

Step C

Preparation of [5ξ,6S-(6R*, 9R*, 13S*)]-4,4,-Difluoro-5- hydroxy-9-(1-methylethyl)-3,8,11-trioxo-1,13-diphenyl-6- [[4-(phenylmethoxy)phenyl]methyl]-12-oxa-2,7,10- triazatetradecan-14-oic Acid, Methyl Ester.

Reaction Scheme D, steps (b) and (c): A flask

containing the major diastereomer of [3ξ,4(S)]-2,4,5- Trideoxy-4-[[2-[[(1,1-dimethylethoxy)carbonyl]amino]-3- methyl-1-oxobutyl]amino-5-[4-(phenylmethoxy)phenyl]-N- (phenylmethyl)-L-glycero-pentonamide (403 mg, 0.630 mmol) is submersed in an ice bath and ice-cold trifluoroacetic acid (TFA) (5 mL) is added with stirring. After 30 minutes, the solution is concentrated under vacuum at 25°C and the residue is carefully partitioned between ethyl acetate and aqueous saturated sodium bicarbonate. The organic layer is separated, washed with brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum to provide 334 mg (98%) of deprotected amine which is immediately suspended in CH₂CI₂ (5 mL) at 0°C and treated with NMM (77 μL, 0.70 mmol) and the chloroformate prepared above (160 mg, 0.70 mmol) dissolved in CH₂CI₂ (1 mL). After stirring for 1.5 hours, the reaction mixture is poured into ethyl acetate/dilute aqueous ammonium chloride. The organic layer is separated, washed with dilute aqueous sodium bicarbonate, brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum. Flash chromatography (4:1 CH₂Cl₂/ethyl acetate) of the residue provides 332 mg (72%) of a single diastereomer of the title compound as a white foam: ¹H NMR (CDCI₃) δ 7.44-7.26 (m, 15 H), 7.12 (d, 2 H, J=8.4 Hz), 6.89 (d, 2 H, J=8.4 Hz), 6.53 (d, 1 H, J=8.4 Hz), 5.89 (s, 1 H), 5.40 (d, 1 H, J=7.9 Hz), 5.02 (s, 2 H), 4.70 (d, 1 H, J=7.0 Hz), 4.49 (apparent d, 2 H, J=5.8 Hz), 4.3-4.1 (m, 2 H), 3.85 (dd, 1 H, J=7.8, 5.5 Hz), 3.63 (s, 3 H), 3.05-2.87 (m, 2 H), 2.2-2.04 (m, 1 H), 1.90 (s, 1 H), 0.83 (d, 3 H, J=6.7 Hz), 0.71 (d, 3 H, J=6.8 Hz); ¹⁹F NMR (CDCI₃) δ -116.60 (dd, 1 F, J=259, 9 Hz), - 118.73 (dd, 1 F, J=259, 15 Hz).

Step D

Preparation of final title compound.

Reaction Scheme A', step (f): The above prepared alcohol is subjected to Swern Oxidation conditions in a manner analogous to that described previously in example 1, step G. The residue is purified by flash chromatography (4:1 CH₂Cl₂/ethyl acetate) to provide 52% of the final title compound. Precipitation with pentane from an ethyl acetate solution provides 29% of final title compound as a white powder: IR (KBr) v_max 3399, 3316, 1745, 1699, 1668, 1534, 1513, 1241 cm^-1; ¹H NMR (CDCI₃) δ 5.89, 5.87, and 5.82 (3s in 6.0:1.8:1.0 ratio, 1 H); 5.05 and 5.03 (2s in 1:1.6 ratio, 2 H); 3.69, 3.67, and 3.65 (3s in 2.5:1.0:1.9 ratio, 3 H); ¹⁹F NMR (CDCI3) δ -112.53 (s), -112.60 (s), -116.25 (d, J=256 Hz), -117.00 (d, J=256 Hz), -120.21 (d, J=256 Hz), -120.78 (d, J=256 Hz), (s: d ratio 4:1); mass

spectrum, m/z 770 (M⁺ + 41), 758 (M⁺ + 29), 731, 730 (M⁺ + 1, 100); exact mass calcd for C₄₀H₄₂F₂N₃O₈ 730.2940, found 730.2925; [α]²⁰ _D -48.3° (c 1.22, CH₃OH). Anal. Calcd for C₄₀H₄₁F₂N₃O₈: C, 65.83; H, 5.66; N, 5.76. Found: C, 65.16; H, 5.69; N, 5.79.

Example 3

Preparation of α,α-Difluoro-γ-[[3-methyl-1-oxo-2-[[(1- oxo-trans-3-phenyl-2-propenyl)amino]butyl]amino]-β-oxo-4- (phenylmethoxy)-N-(phenylmethyl)-benzene-pentanamide.

Step A

Preparation of N-(trans-Cinnamoyl)-L-valine

To a stirred solution of L-valine methyl ester

hydrochloride (1.97 g, 11.8 mmol) and NMM (1.10 g, 10.8 mmol) in CH₂CI₂ (15 mL) and DMF (20 mL) is added a solution of 1-trans-cinnamoylimidazole (2.15 g, 10.8 mmol) in CH₂CI₂ (28 mL). After 18 h, additional L-valine methyl ester hydrochloride (0.36 g, 2.1 mmol) is added and the reaction mixture is stirred for 5 h before being diluted with water (100 mL) and extracted with CHCl₃. The organic extract is washed with three portions of water, dried (MgSO₄), and concentrated in vacuo. Filtration through a short silica gel column (1/1 ethyl acetate/cyclohexane) provides 2.0 g (71%) of N-(trans-cinnamoyl)-L-valine methyl ester. To a stirred solution of this ester (13.5 mmol) in CH₃OH (125 mL) and water (5 mL) is added LiOH-H₂O (0.59 g, 14 mmol). After 17 hours an additional amount of LiOH-H₂O (0.06 g) is added and stirring is continued for 2 hours. The solutio is concentrated in vacuo and the residue is diluted with water (100 mL) and washed with ether. The aqueous layer acidified with ice-cold 6 N HCl and extracted with two portions of ether. The combined extracts are washed with water and dried (MgSO4). Concentration in vacuo provides 67% of the title compound as a white solid: mp 63-68°C; (CHCl₃) v_max 3008, 2970, 1718, 1670, 1629, 1512, 1196, 667 cm^-1; ¹H NMR (CDCI₃) δ 9.94 (bs, 1 H), 7.65 (d, 1 H, J=15.6 Hz), 7.50-7.46 (m, 2 H), 7.35-7.31 (m, 3 H), 6.56 (d, 1 H, J=8.7 Hz), 6.52 (d, 1 H, J=15.6 Hz), 4.75 (dd, 1 H, J=8.7, 4.8 Hz), 2.34-2.28 (m, 1 H), 1.02 (d, 3 H, J=6.9 Hz), 0.99 (d, 3 H, J=6.6 Hz); ¹³C NMR (CDCI₃) δ 175.31, 166.66, 142.42, 134.50, 129.93, 128.79, 127.94, 119.75, 57.47, 31.19, 19.00, 17.78; mass spectrum, m/z 276 (M⁺ + 29), 248 (M⁺ + 1), 203, 131 (100); exact mass calcd for C₁₄H₁₈NO₃ 248.1287, found 248.1290; [α]²⁰ _D +24.1° (c 1.02, CH₃OH). Anal. Calcd for C₁₄H₁₇NO₃·0.1H₂O: C, 67.51; H, 6.96; N, 5.62. Found: C, 67.30; H, 7.10; N, 5.57.

Step B

Preparation of [3ξ,4(S)]-2,4,5-Trideoxy-2,2-difluoro-4-[[3- methyl-1-oxo-2-[(1-oxo-trans-3-phenyl-2- propenyl)amino]butyl]amino]-5-[4-(phenylmethoxy)phenyl]-N- (phenylmethyl)-L-glycero-pentanamide.

Reaction Scheme A', step (e): N-(trans-Cinnamoyl)-L- valine prepared above (25 mmol) is dissolved in CH₃CN (80mL) and the resulting solution cooled to -10°C. To the stirred solution is added N-methylmorpholine (2.52 g, 24.9 mmol, NMM), followed by isobutylchloroformate (3.72 g, 27.2 mmol). After 10 minutes, a solution of 4-amino-2,2- difluoro-3-hydroxy-5-(4-benzyloxy)phenyl-N-(phenylmethyl) pentanamide (43.7 mmol, prepared in example 1, step D and NMM (4.08 g, 40.3 mmol) in H₂O (20 mL) is added and stirring is continued at -10°C for 20 minutes. The reaction mixture is poured into ice-cold dilute HCl containing some NaCl and is extracted with two portions of ethyl acetate. The combined extracts are washed with water, aqueous saturated sodium bicarbonate, brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum. The residue is recrystallized from ethyl acetate/pentane to provide 61% of a 2:1 mixture of diastereomers of title compound as a light tan solid: mp 222-227°C; IR (KBr) v_max 3410, 3287, 1682, 1652, 1620, 1540, 1512, 1243, 1217, 697 cm^-1; ¹H NMR (DMSO-d₆) δ 9.17-9.11 (m, 1 H), 8.05 and 8.01 (2d, 1 H total, J=9.1, 9.1 Hz), 7.85 and 7.71 (2d, 1 H total, J=9.1, 9.0 Hz), 7.59-7.22 (m, 16 H), 7.12 (d, 2 H, J=8.5 Hz), 6.94-6.85 (m, 3 H), 6.26 (d, 1 H, J=7.6 Hz), 5.04 and 4.96 (2s, 2 H total), 4.42-3.99 (m, 5 H), 2.79- 2.63 (m, 2 H), 2.09-1.98 and 1.92-1.85 (2m, 1 H total), 0.86 and 0.74 (2d, 3 H total, J=6.9 Hz), 0.83 and 0.64 (2d, 3 H total, J=6.9 Hz); ¹⁹F NMR (DMSO-d₆) δ -111.11 (dd, J=255, 6 Hz), -112.12 (dd, J=254, 8 Hz), -120.35 (dd,

J=254, 19 Hz), -122.04 (dd, J=255, 20 Hz); mass spectrum, m/z 698 (M⁺ + 29), 670 (M⁺ + 1, 100), 650, 441, 423. Anal. Calcd for C₃₉H₄₁F₂N₃O₅: C, 69.94; H, 6.17; N, 6.27. Found: C, 68.59; H, 6.32; N, 5.90.

Step C

Preparation of the final title compound.

Reaction Scheme A', step (f): The above prepared alcohol is oxidized under Swern conditions as follows: To a stirred solution of 2 M oxalyl chloride/CH₂Cl₂ (2.0mL) at -60°C under nitrogen is added dropwise anhydrous DMSO (0.42 mL, 5.9 mmol). After 10 minutes, a solution of the above prepared alcohol (0.50 mmol) in CH₂CI₂ (3 mL) and anhydrous DMSO (1.5 mL) is added. The solution is allowed to stir at -65 to -55°C for 5 hours. It is then warmed to -20°C, followed by addition of triethylamine (1.39 mL, 10.0 mmol) over 5 minutes. The reaction mixture is then allowed to warm to room temperature overnight. It is then diluted with ethyl acetate (60 mL) and filtered, washing the solids with ethyl acetate. The filtrate is washed with 0.1 M HCl (3 x 15 mL), brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum. Flash

chromatography (6% acetone in CH₂CI₂) followed by

recrystallization from ethyl acetate/pentane provides 34% of the final title compound as a white solid: mp 187-194ºC; IR (KBr) v_max 3403, 3285, 1691, 1654, 1623, 1540, 1513, 1454, 1243, 1219, 1178, 697 cm^-1; ¹H NMR (DMSO-d₆) δ 9.77- 9.68 (m, 1 H), 8.67-8.62 (m 1 H), 8.05-8.00 (m, 1 H), 7.56 (d, 2 H, J=7.0 Hz), 7.50-7.21 (m, 14 H), 7.14 (d, 2 H, J=8.5 Hz), 6.91-6.83 (m, 3 H), 5.04-4.95 (m, 3 H), 4.42- 4.33 (m, 3 H), 3.14-3.05 (m, 1 H), 2.74-2.61 (m, 1 H), 2.02-1.76 (m, 1 H), 0.84 and 0.81 (2d, 3 H total, J=7.0, 6.9 Hz), 0.64 and 0.59 (2d, 3 H total, J=7.1, 6.9 Hz); ¹⁹F NMR (DMSO-d₆) δ -110.26 (d, J=269 Hz), -110.53 (d, J=268 Hz),-112.03 (d, J=269 Hz), -112.04 (d, J=268 Hz)-major diastereomer pair; -105.07 (d, J=265 Hz), -105.08 (d,

J=266 Hz), -110.59 (d, J=265 Hz), -110.61 (d, J=266 Hz)- minor diastereomer pair; mass spectrum, m/z 696 (M⁺ + 29), 668 (M⁺ + 1), 439, 230, 202, 131, 124, 91 (100); exact mass calcd for C₃₉H₄₀F₂N₃O₅ 668.2936, found 668.2953; [α]²⁰ _D +7.23° (c 0.622, DMSO-d₆). Anal. Calcd for C₃₉H₃₉F₂N₃O₅: C, 70.15; H, 5.89; N, 6.29. Found: C, 69.63; H, 5.85; N, 6.01.

Example 4

Preparation of α,α-Difluoro-γ-[[2-[2-hydroxy-1-oxo-4- (phenylbutyl)amino]-3-methyl-1-oxobutyl]amino]-B-oxo-4- (phenylmethoxy)-N-(phenylmethyl)-benzene-pentanamide.

Step A

Preparation of (R)-[[2-[(1,1-

Dimethylethyl)dimethylsilyl]oxy]-4-phenylbutyryl]-L-valine.

(R)-(-)-2-hydroxy-4-phenylbutyric acid is coupled with L-valine methyl ester hydrochloride under standard coupling conditions in a manner analogous to that described

previously, such as example 2, step A, to provide (R)-(2- hydroxy-4-phenylbutyryl)-L-valine methyl ester as a yellow solid in 89% yield. Treatment with tert-butyldimethylsilyl chloride in a manner analogous to that described previously in example 1 for the preparation of N-(R)-[[[(1,1- dimethylethyl)dimethyIsilyl]oxy]phenylacetyl]-L-valine provides the ester of the title compound as a colorless oil in 83% yield after flash chromatography (9/1

cyclohexane/ethyl acetate). The ester is hydrolyzed with LiOH•H₂O in a manner analogous to that described previously in example 1 for the preparation of N-(R)-[[[(1,1- dimethylethyl)dimethylsilyl]oxy]phenylacetyl]-L-valine to provide the title compound in 58% yield as a white solid: mp 110-113°C; IR (KBr) v_max 3387, 2958, 2932, 2897, 2860, 1719, 1626, 1531, 1251, 1097, 839 cm^-1; ¹H NMR (CDCl₃) δ 7.24-7.12 (m, 7 H), 4.54 (dd, 1 H, J=8.7, 4.5 Hz), 4.32 (t, 1-H, J=4.8 Hz), 2.76-2.55 (m, 2 H), 2.36-2.25 (m, 1 H), 2.19-2.07 (m, 1 H), 2.02-1.90 (m, 1 H), 1.00 (d, 3 H, J=7.2 Hz), 0.97 (d, 3 H J=6.9 Hz), 0.97 (s, 9 H), 0.13 (s, 3 H), 0.10 (s, 3 H); ¹³C NMR (CDCI₃) δ 175.64, 174.08, 141.69, 128.42, 128.30, 125.77, 72.73, 59.64, 36.98, 30.75, 30.02, 25.67, 19.05, 17.93, 17.54, -4.79, -5.15; mass spectrum, m/z 394 (M⁺ + 1), 393 (M+), 378, 336 (100), 289, 117, 91, 73; [α]²⁰ _D +13.7° (c 1.00, CH₃OH). Anal. Calcd for

C₂₁H₃₅NO₄Si: C, 64.08; H, 8.96; N, 3.56. Found: C, 63.87; H, 9.07; N, 3.45.

Step B

Preparation of [3ξ,4(S,R)]-2,4,5-Trideoxy-4-[[2-[[2-[[(1,1 dimethylethyl)dimethyIsilyl]oxy]-1-oxo-4- phenylbutyl]amino]-3-methyl-1-oxobutyl]amino]-5-[4- (phenylmethoxy)phenyl]-N-(phenylmethyl)-L-glycero- pentanamide.

Reaction Scheme A', step (e): (R)-[[2-[(1,1- Dimethylethyl)dimethylsilyl]oxy]-4-phenylbutyryl]-L-valine is coupled with 4-amino-2,2-difluoro-3-hydroxy-5-(4- benzyloxy)phenyl-N-(phenylmethyl)pentanamide prepared in example 1, step D under standard coupling conditions in a manner analogous to that described previously, such as in example 2, step A, to provide the title compound after flash chromatography (6% acetone in CH₂CI₂) as a tan foam in 61% yield: mp 62-67°C; ¹H NMR (CDCI₃) δ 7.44-7.11 (m, 17 H), 7.04 (d, 2 H, J=8.7 Hz), 6.86 (d, 2 H, J=8.7 Hz), 6.11 (d, 1 H, J=8.1 Hz), 5.01 (s, 2 H), 4.71 (d, 1 H, J=6.9 Hz), 4.52 (dd, 1 H, J=14.6, 6.5 Hz), 4.35 (dd, 1 H, J=14.4, 5.4 Hz), 4.28 (t, 1 H, J=4.8 Hz), 4.15-3.93 (m, 3 H), 2.91 (d,

2 H, J=7.8 Hz), 2.72 (ddd, 1 H, J=13.2, 12.0, 4.8 Hz), 2.57 (ddd, 1 H, J=13.5, 12.3, 5.4 Hz), 2.15-1.90 (m, 3 H), 0.98 (s, 9 H), 0.87 (d, 3 H, J=2.4 Hz), 0.85 (d, 3 H, J=2.1 Hz), 0.14 (s, 3 H), 0.10 (s, 3 H); ¹⁹F NMR (CDCI₃) δ -117.17 (dd, J=259, 15 Hz), -118.62 (dd, J=259, 10 Hz); mass spectrum, m/z 844 (M⁺ + 29), 816 (M⁺ + 1), 758, 469, 441, 423 (100), 91; [α]²⁰ _D -30.6° (c 0.547, CH₃OH) . Anal. Calcd for

C₄₆H₅₉F₂N₃O₆Si: C, 67.70; H, 7.29; N, 5.15. Found: C, 67.32; H, 7.22; N, 5.15. Step C

Preparation of final title compound.

Reaction Scheme A', steps (f) and (g): The above prepared alcohol is oxidized under Swern conditions in a manner analogous to that described previously in example 1, step G to provide the protected ketone as a light brown oil in 72% yield after flash chromatography (6% acetone in CH₂CI₂). Deprotection of the ketone (217mg) in a manner analogous to that described previously in example 1, step G provides the title compound after flash chromatography (6, 10, and finally 15% acetone in CH₂CI₂), 104 mg (58%) as a light yellow glass. Crystallization from CH₂Cl₂/ether and three recrystallizations from ethyl acetate/pentane

provides 34 mg (19%) of title compound as a white solid: IR (KBr) v_max 3394, 3300, 1686, 1651, 1534, 1513, 1498, 1243, 698 cm^-1; ¹H NMR (DMSO-d₆) δ 9.76-9.69 (m, 1 H) 8.70-8.66 (m, 1 H), 7.52-7.11 (m, 19 H), 6.88 and 6.87 (2d, 2 H total, J=8.7 Hz), 5.73 (t, 1 H, J=5.8 Hz), 5.03 and 5.00 (2s overlapping m, 3H total, J=8.3 Hz), 4.35 (apparent d, 2 H, J=6.1 Hz), 4.26-4.20 (m, 1 H), 3.94-3.87 (m, 1 H), 3.15- 3.06 (m, 1 H), 2.73-2.58 (m, 2 H), 1.96-1.66 (m, 3 H), 0.77 and 0.76 (2d, 3 H total, J=6.7 Hz), 0.63 and 0.53 (2d, 3 H total, J=6.8, 6.6 Hz); ¹⁹F NMR (DMSO-d₆) δ -110.35 (d, J=268 Hz), -110.47 (d, J=268 Hz), -112.14 (d, J=268 Hz), -112.20 (d, J=268 Hz); mass spectrum, m/z 700 (M⁺ + 1), 680, 622, 439 (100), 421, 254, 91.

Example 5

Preparation of N-[1-[[[3,3-Difluoro-4-[[2-methyl-1- [(phenylmethoxy)methyl]-propyl]amino]-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]-methyl]butyl]amino]carbonyl]-2- methylpropyl]-8-oxo-4-morpholinepropanamide.

Step A

Preparation of [1 (R), 3ξ , 4(S)]-2,4,5-Trideoxy-4-[[(1,1- dimethylethoxy)-carbonyl]amino]-2,2-difluoro-N-[2-methyl-1- [(phenylmethoxy)methyl]propyl]-5-[4-(phenylmethoxy)phenyl]- L-glycero-pentanamide.

Reaction Scheme A, step (b): To a stirred solution of O-benzyl-D-valinol (5.42 g, 28.0 mmol) in CH₂CI₂ (15 mL) is added a 2 M solution of (CH₃) ₃Al/toluene (14.0 mL, 28.0 mmol) over 20 minutes. During the addition more CH₂CI₂ (10 mL) is added to convert the resulting paste to a thin slurry. As the addition proceeds, a solution again forms with vigorous gas evolution as it warms to reflux. After the addition is complete, the solution is allowed to stir at reflux for 15 minutes as gas evolution subsides. The solution is allowed to cool to room temperature and a solution of 4-tert-butoxycarbonylamino-2,2-difluoro-3- hydroxy-5-(4-benzyloxy)phenylpentanoic acid, ethyl ester (5.38 g, 11.2 mmol, prepared in example 1) in CH₂CI₂ (20 ml) is added over 15 minutes with moderate gas evolution. T resulting solution is heated at reflux overnight. The reaction mixture is cooled to 0°C and carefully quenched with excess methanol. The resulting solution is washed with 1 N HCl. The aqueous layer is extracted with ether. The combined organic extracts are washed with water, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum to provide after flash chromatography (4:1 cyclohexane/ethyl acetate) 5.5 g (78%) of title compound as a beige powder. Step B

Preparation of [1 (R), 3ξ, 4(S)]-4-Amino-2,4,5-trideoxy- 2,2-difluoro-N-[2-methyl-1-[(phenylmethoxy)methyl]propyl]- 5-[4-(phenylmethoxy)phenyl]-L-glycero-pentanamide.

Reaction Scheme A, step (d): A solution of the above prepared alcohol (3.6 g, 5.7 mmol) in HCO₂H (50 mL) is allowed to stir at room temperature for 3 hours. The solution is then concentrated under vacuum at 35°C. The residue is dissolved in ethyl acetate and aqueous sodium bicarbonate is added with vigorous stirring. The layers are separated and the organic layer is washed with water. The combined aqueous layers are again extracted with ethyl acetate. The combined organic extracts are dried anhydrous magnesium sulfate, filtered and concentrated under vacuum to provide 3.0 g (99%) of the title compound as an orange oil.

Step C

Preparation of [1 (R), 3ξ, 4(S)]-2,4,5-Trideoxy-4-[[2-

[[(1,1-dimethylethoxy)carbonyl]amino]-3-methyl-1- oxobutyl]amino]-2,2-difluoro-N-[2-methyl-1- [(phenylmethoxy)methyl]propyl]-5-[4-(phenyl- methoxy)phenyl]-L-glycero-pentanamide .

Reaction Scheme D, step (a): The above prepared amine is coupled under standard conditions in a manner analogous to that described previously, such as exmaple 2, step A, with N-(tert-butoxycarbonyl)-L-valine (1.21 g, 5.61 mmol) to provide, after flash chromatography (9:1 CH₂Cl₂/ethyl acetate), 2.3 g (60%) of title compound as a yellow powder. Step D

Preparation of [1 (R), 3ξ, 4(S)]-4-[[2-Amino-3-methyl-1 oxobutyl]aminol-2,4,5-trideoxy-2,2-difluoro-N-[2-methyl-1- [(phenylmethoxy)methyl]-propyl]-5-[4- (phenylmethoxy)phenyl]-L-glycero-pentanamide.

Reaction Scheme D, step(b): A solution of the above

prepared amide (2.0 g, 2.8 mmol) in HCO₂H (25 mL) is allowed to stir at room temperature for 6 hours. The solution is concentrated under vacuum at 30°C and the residue is dissolved in ethyl acetate. Aqueous sodium bicarbonate is added with vigorous stirring. White solids precipitate out which are filtered and found to be the formate salt of the (S)-amino alcohol. The organic layer of the filtrate is separated, washed with water, dried over anhydrous

magnesium sulfate, filtered and concentrated under vacuum to provide an amber oil containing some white solids; both the (R)- and (S)-amino alcohol and the lactam by-product are present. The residue is slurred in CHCl₃ for 1 hour and the precipitated solids, again the formate salt of the (S)- amino alcohol, are collected. The filtrate is concentrated under vacuum and the residue dissolved in CH₂CI₂ and

additional formate salt of the (S)-amino alcohol is collected. Flash chromatography of the residual oil (5:1 CH₂Cl₂/ethyl acetate to remove the lactam, then 9:1 CH₂Cl₂/ CH₃OH) provides a yellow semi-solid which is the (R)-amino alcohol contaminated with 5% of the formate of the (S)- amino alcohol. Yield: 800 mg (43%) of the formate salt of the (S)-amino alcohol and 640 mg (37%) of the (R)-amino alcohol. To a stirred suspension of the formate salt of the (S)-amino alcohol (800 mg, 1.19 mmol) in ethyl acetate added 10% aqueous sodium bicarbonate. After 2 hours at room temperature, the solids dissolve. The organic layer is separated, washed with water, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum to provide 712 mg (95%) of title compound as a white powder: mp 160-164°C; IR (KBr) umax 3383, 3327, 1676, 1632, 1530, 1514, 1244, 1109 cm^-1; ¹H NMR (CDCI₃) δ 7.73 (d, 1H, J = 6.9 Hz), 7.43-7.29 (m, 10 H), 7.10 (d, 2 H, J = 8.4 Hz), 6.90 (d, 2 H, J = 8.7 Hz), 6.78 (d, 1 H, J = 9.0 Hz), 5.56 (bs, 1 H), 5.04 (s, 2 H), 4.55 (d, 1 H, J = 12.0 Hz), 4.47 (d, 1 H, J = 12.0 Hz), 4.33-4.18 (m, 2 H), 3.92-3.83 (m, 1 H), 3.60 (dd, 1 H, J = 9.6, 3.6 Hz), 3.45 (dd, 1 H, J = 9.6, 3.6 Hz), 3.16 (d, 1 H, J = 3.9 Hz), 3.03-3.00 (m, 2 H), 2.18-1.93 (m, 2 H), 1.44 (bs, 2 H), 0.94 (d, 6 H, J = 6.9 Hz), 0.85 (d, 3 H, J = 6.9 Hz), 0.53 (d, 3 H, J = 6.9 Hz); ¹⁹F NMR (CHCl₃) δ -110.67 (dd, J = 259, 5 Hz), - 121.74 (dd, J = 258, 18 Hz); mass spectrum, m/z 654 (M⁺ + 29), 626 (M⁺ + 1), 325, 92, 91 (100), 72. Anal. Calcd for C₃₅H₄₅F₂N₃O₅: C, 67.18; H, 7.25; N, 6.72. Found: C, 67.34; H, 7.21; N, 6.66. Step E

Preparation of [1 (R), 3ξ, 4 (S)]-2,4,5-Trideoxy-2,2- difluoro-4-[[3-methyl-2-[[3-(4-morpholinyl)-1,3- dioxopropyl]amino]-1-oxobutyl]amino]-N-[2-methyl-1- [(phenylmethoxy)methyl]propyl]-5-[4-(phenyl- methoxy)phenyl]-L-glycero-pentanamide.

Reaction Scheme D, step (c): The (R)-amino alcohol prepared above (169 mg, 0.270 mmol) is coupled under standard coupling conditions described previously, such as example 2, step A, with 2-(4-morpholinylcarbonyl)ethanoic acid (49 mg, 0.28 mmol, compound (B) prepared in example

5a) to provide, after flash chromatography (3% CH₃OH/CHCl₃), 185 mg (88%) of title compound as a tan powder: mp 87-94°C; IR (KBr) v_max 3428, 3325, 1651, 1535, 1512, 1454, 1238, 1115 cm^-1; ¹⁹F NMR (CDCI₃) δ -116.11 (d, J = 259 Hz), - 119.49 (dd, J = 259, 15 Hz); mass spectrum, m/z 809 (M⁺ + 29), 781 (M⁺ + 1) 509, 255, 243, 227, 88 (100).

Step F

Preparation of final title compound.

Reaction Scheme D, step (d): The above prepared alcohol (177 mg, 0.283 mmol) is oxidized under Swern conditions in a manner analogous to that described in example 1, step G to provide 170 mg (100%)of the final title compound after flash chromatography (3% CH₃OH/CHCl₃). Recrystallization from CH₂Cl₂/ether provides 49 mg (28%) of final title compound as pale tan powder: mp 119-128°C; IR (KBr) v_max 3306, 1661, 1638, 1539, 1514, 1454, 1238, 1117 cm^-1; ¹H NMR (CDCI₃) δ 7.77 and 7.75 and 7.61 and 7.47 (4d, 1 H total, J = 7.1, 7.1, 8.7, 8.9 Hz respectively), 7.43- 7.29 (m, 10 H), 7.16-7.03 (m, 3H), 6.91-6.72 and 6.38-6.35 (2m, 3 H total), 5.74 and 5.53-5.46 and 5.24-5.17 (bs and 2m, 1 H total) 5.02 (s, 2 H), 4.56 and 4.48 (2d, 1 H total, J = 12.1 Hz), 4.55 and 4.47 (2d, 1 H total, J = 12.0 Hz), 4.27 and 4.23 and 4.12 (3dd, 1 H total, J = 8.8, 5.3 and 8.7, 5.7 and 7.3, 5.1 Hz respectively), 3.89-3.80 (m, 1 H), 3.69-3.59 (m, 7 H), 3.52-3.40 (m, 3 H), 3.32-3.21 (m, 3 H), 2.94-2.75 (m, 1 H), 2.29-1.87 (m, 2 H), 0.94 and 0.93 and 0.92 and 0.91 and 0.89 and 0.88 and 0.84 and 0.81 and 0.80 and 0.76 and 0.59 and 0.55 (12d, 12 H total, J = 6.8 and 7.0 and 7.0 and 6.9 and 6.9 and 7.0 and 7.0 and 7.0 and 6.8 and 6.8 and 6.9 and 6.8 Hz respectively); ¹⁹F NMR (CDCI₃) δ -114.46 (d, J = 274 Hz), -112.74 (s), -113.47 (d, J = 274 Hz), Hydrate: -114.43 (d, J - 253 Hz), -116.47 (d, J = 254 Hz), -120.63 (d, J = 253 Hz), -122.73 (d, J = 253 Hz); mass spectrum, m/z 807 (M⁺ + 29), 779 (M⁺ + 1), 401, 361, 243 (100), 227; exact mass calcd for C₄₂H₅₃F₂N₄O₈ 779.3831, found 779.3878.

Example 5a

Preparation of 4-Morpholine acetic acid, trifluoroacetic acid salt (A) and 2-(4-Morpholinylcarbonyl)ethanoic acid (B).

Preparation of 4-Morpholine acetic acid, 1,1-dimethylethyl ester.

To a stirred solution of t-butyl bromoacetate (1.61 mL, 10.0 mmol) in tetrahydrofuran (25 mL) is added morpholine (1.74 mL, 20.0 mmol). The suspension is stirred for 1.5 hours and then concentrated under vacuum. The residue is dissolved in methylene chloride (50 mL) with saturated sodium carbonate (50 mL). The layers are separated and the aqueous is extracted methylene chloride (2 x 25 mL). The organic extracts are combined, washed with saturated sodium carbonate (20 mL), brine (30 mL), dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum. The residue is triturated with ethyl acetate (15 mL), filtered and the filtrate concentrated under vacuum to provide the title compound (2.01 g) as a colorless oil; TLC R_f = 0.45 (ethyl acetate, silica gel).

Preparation of final title compound (A).

Trifluoroacetic acid (15 mL) is added to the above prepared ester (1.00 g, 4.97 mmol). The solution is stirred for 5 hours and then concentrated under vacuum to provide a yellow oil. This is triturated with diethyl ether (25 mL) to provide the final title compound (A) (1.06 g, 82%) as an off white solid; mp 118-121°C. Preparation of 2-(4-Morpholinylcarbonyl)ethanoic acid, methyl ester.

To a solution of methylmalonyl chloride (10.0 g, 73.2 mmol) in methylene chloride (200 mL) at 0°C is added rapidly dropwise a solution of morpholine (16.0 g, 0.183 mmol, 16.0 mL) in methylene chloride (50 mL). The reaction is stirred for 4 hours at room temperature. The reaction is then filtered and the filtrate is diluted with additional methylene chloride (200 mL). This is then washed with 1 N HCl, saturated sodium bicarbonate and brine. The organic is then concentrated under vacuum to provide a yellow oil, which is purified by flash chromatography (ethyl acetate, silica gel) to provide the title compound (9.7 g, 71%) as a pale yellow oil; R_f = 0.28 (ethyl acetate).

Preparation of final title compound (B).

To a solution of the above prepared amide (1.70 g, 9.08 mmol) in methanol (45 mL) is added 1N lithium hydroxide (10 mL, 9.99 mmol). The reaction is stirred at room

temperature for 2.5 hours. The pH is adjusted to 3 with 1N HCL and the reaction is concentrated under vacuum. The residue is recrystallized from acetonitrile to provide the title compound (B) (0.216 g, 14%) as a white solid.

Example 6

[ 1R- ( 1R* , 2S* ) ] -α , α-Dif luoro-γ- [ [ 2- ( R) -

[[(hydroxy)phenylacetyl]-amino]-3-methyl-1-oxobutyl]amino]- N-[2-methyl-1-[(phenylmethoxy)methyl]propyl]-β-oxo-4- (phenylmethoxy)-benzenepentanamide.

Step A

Preparation of [1 (R), 3ξ, 4(S)]-2,4,5-Trideoxy-4-[[2-[[4- [[2-[[[[(1,1-dimethyl- ethyl)dimethylsilyl]oxyjphenylacetyl]amino]-3-methyl-1- oxobutyl]amino]-2,2-difluoro-N-[2-methyl-1- [(phenylmethoxy)-methyl]propyl]-5-[4-(phenylmethoxy)- phenyl]-L-glycero-pentanamide.

Reaction Scheme A', step (e): [1 (R), 3ξ, 4(S)]-4- Amino-2,4,5-trideoxy-2,2-difluoro-N-[2-methyl-1- [(phenylmethoxy)methyl]propyl]-5-[4-(phenyl- methoxy)phenyl]-L-glycero-pentonamide (0.87 g, 1.6 mmol) prepared in example 5, step B, is coupled under standard coupling conditions in a manner analogous to that described previously, such as example 2, step A, with (R)-O-tert- butyldimethyl-silylmandelic acid (0.44 g, 1.2 mmol)

prepared in example 1 to provide the title compound, after flash chromatography (3:2, then 1:1 hexane/ethyl acetate), 0.36 g (35%) as a yellow oil: IR (film) v_max 3405, 3325, 2959, 2932, 2895, 2876, 2861, 1684, 1657, 1512, 1470, 1454, 1244, 1221, 1179, 1098, 864 cm^-1; ¹⁹F NMR (CHCl₃) δ -117.20 (d, J = 258 Hz), -118.99 (s), -120.55 (d, J = 262 Hz); mass spectrum (CI, 70 eV), m/z 874 (M⁺ + 1), 509, 221 (100); exact mass calcd for C₄₉H₆₆F₂N₃O₇Si 874.4638, found 874.4651. Step B

Preparation of final title compound.

Reaction Scheme A', steps (f) and (g): The above prepared alcohol (345 mg, 0.39 mmol) is oxidized under Swern conditions in a manner analogous to that described

previously in example 1 to provide after flash

chromatography (3:2 hexane/ethyl acetate), 154 mg ( 45%) of the ketone as a yellow glass: IR (film) v_max 3408, 3298, 2961, 2932, 2861, 1655, 1613, 1514, 1470, 1454, 1246, 1179, 1098, 1072, 839 cm^-1; ¹⁹F NMR (CDCI₃) δ -112.68 (s), -117..29 (d, J = 253Hz), -120.03 (d, J = 253 Hz); mass spectrum (CI, 70 eV), m/z 872 (M⁺ + 1), 221 (100), 197; exact mass calcd for C₄₉H₆₄F₂N₃O₇Si 872.4482, found 872.4500. To a stirred solution of ketone in CH₂CI₂ (4 mL) is added TFA/H₂O (9:1, 1 mL). The reaction mixture is allowed to stir at room temperature for 7 hours and then

concentrated under vacuum. The residue is dissolved in CH₂CI₂ and the solution is washed with saturated aqueous sodium bicarbonate, brine, dried over anhydrous magnesium sulfate, filtered and concentrate under vacuum. The residue is purified by flash chromatography (1:1

hexane/ethyl acetate) to provide 85 mg (64%) of the final title compound as a white powder: IR (film) v_max 3397, 3314, 2965, 2934, 2874, 1750, 1688, 1663, 1532, 1514, 1468, 1454, 1242, 1179, 1113, 826 cm^-1; ¹⁹F NMR (CDCI₃) δ -112.30 (d, J = 271 Hz), -113.50 (d, J = 271 Hz), -117.54 (d, J = 254 Hz), -119.32 (d, J = 254 Hz); mass spectrum (CI, 70 eV), m/z 758 (M⁺ + 1), 107 (100), 91. Anal. Calcd for

C₄₃H₄₉F₂N₃O₇•0.6H₂O: C, 67.11; H, 6.58; N, 5.47. Found: C, 67.11; H, 6.55; N, 5.39. Example 7

Preparation of N-[1-[[[3,3-Difluoro-4-[[2-methyl-1- [(phenylmethoxy)-methyl]-propyl]amino]-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]- methyl)-butyl]amino]carbonyl]-2- methylpropyl]-6-(4-morpholinyl-carbonyl)-3- pyridinecarboxamide.

Step A

Preparation of 6-(4-Morpholinylcarbonyl)-3- pyridinecarboxylic Acid.

To a stirred 1 M solution of O-tert-butyl-N,N '- dicyclohexylisourea [see Mathias, L., Synthesis, 570, 1979, for preparation] in CH₂CI₂ (20 mL) at 5°C under nitrogen is added 1.49 g (8.24 mmol) of 2-methyl isocinchomeronate [see Isagawa, K., et al., Nippon Kaqaku Zasshi, 88, 553, 1967, for preparation] in portions over 2 minutes. After 15 minutes, the cold water bath is removed. As

dicyclohexylurea begins to precipitate, the reaction mixture is again be placed in a cool water bath at

15-20°C. The mixture is diluted with CH₂CI₂ (5 mL) and allowed to stir at room temperature overnight. The mixture is then diluted with CH₂CI₂ (30 mL), filtered, and the blue- green solids are washed with CH₂CI₂. The filtrate and washings are diluted with ether and washed with dilute aqueous sodium bicarbonate, water, brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum to provide 1.36 g of light blue solids. Flash chromatography (55:45 cyclohexane/ethyl acetate) provides 1.01 g (52%) of the diester below

as white crystals. Recrystallization from ether/pentane provides the above diester as matted white needles: mp 111- 112°C; IR (KBr) v_max 3420, 2984, 1711, 1379, 1310, 1290, 1246, 1134, 1126, 746 cm^-1; ¹H NMR (CHCl₃) δ 9.26 (d, 1 H, J = 2.1 Hz), 8.39 (dd, 1 H, J = 8.1, 2.1 Hz), 8.19 (dd, 1 H, J = 8.1, 0.7 Hz), 4.04 (s, 3 H), 1.63 (s, 9H); mass

spectrum (El), m/z 238 (M⁺ + 1), 237 (M+), 182, 179, 164, 57, (100); CI m/z 238 (M⁺ + 1), 210, 182 (100). Anal. Calcd for C₁₂H₁₅NO₄: C, 60.75; H, 6.37; N, 5.90. Found: C, 60.80; H, 6.31; N, 5.75. A solution of the above diester (935 mg, 3.94 mmol) and morpholine (2.0 mL, 23 mmol) in THF (6 mL) are stirred at reflux under nitrogen for 24 hours.

Additional morpholine (2.0 mL, 23 mmol) is added and heating continued. After 3 more days, the solution is concentrated under vacuum and the residue is dissolved in ethyl acetate and the solution is washed twice with water. The organic layer is concentrated under vacuum to provide 1.01 g of light yellow solid. Two recrystallizations from ether/pentane, with filtration through filter aid, provide 542 mg (47%) of amide ester below

as fine cream-colored crystals: mp 91-93°C; IR (KBr) v_max 2984, 2965, 1707, 1634, 1370, 1317, 1287, 1169, 1132, 1117 cm^-1; ¹H NMR (CDCI₃) δ 9.13 (dd, 1 H, J = 2.1, 1.0 Hz), 8.36 (dd, 1 H, J = 8.1, 2.1 Hz), 7.75 (dd, 1 H, J = 8.1, 0.9 Hz), 3.83 (s, 4 H), 3.73-3.55 (m, 4 H), 1.62 (s, 9 H); mass spectrum, m/z 293 (M⁺ + 1), 292, 123, 86 (100). Anal. Calcd for C₁₅H₂₀N₂O₄: C, 61.63; H, 6.90; N, 9.58. Found: C, 61.62; H, 6.91; N, 9.64. HCl gas is bubbled through a solution of the above amide ester (103.5 mg, 0.354 mmol) in CH₃NO₂ (4-5 mL) for 20-25 minutes. After standing for an additional 20 minutes, the solution is concentrated under vacuum and the residue is triturated with acetone to

provide the title compound (acid) as a pale yellow solid. The material is combined with crude acid from a similar experiment (from 502 mg 14) and recrystallized from acetone to provide (335 mg (69%) of title compound as short, thick white needles: mp 181-183°C; IR (KBr) v_max 2928, 2872, 1717, 1601, 1285, 1262, 1111 cm^-1; ¹H NMR (CD₃OD) δ 9.26 (d, 1 H, J = 1.1 Hz), 8.78 (dd, 1 H, J = 8.1, 2.0 Hz), 8.0 (d, 1 H, J = 8.1, Hz), 3.80 (s, 4 H), 3.67 (nm, 2 H), 3.51 (nm, 2 H); mass spectrum, m/z 277 (M⁺ + 41), 265 (M⁺ + 29), 238, 237 (M⁺ + 1, 100). Anal. Calcd for C₁₁H₁₂N₂O₄: C,

55.93; H, 5.13; N, 11.86. Found: C, 56.15; H, 5.32; N, 11.46.

Step B

Preparation of [1 (R), 3ξ, 4(S)3-2,4,5-Trideoxy-2,2- difluoro-4-[[3-methyl-2-[[[6-(4-morpholinylcarbonyl)-3- pyridinyl]carbonyl]amino]-1-oxobutyl3-amino3-N-[2-methyl-1- [(phenylmethoxy)methyl]-propyl]-5-[4- (phenylmethoxy)phenyl]-L-glycero-pentanamide .

Reaction Scheme D, step (c): The (S)-amino alcohol (185 mg, 0.296 mmol) prepared in example 5, step D, is coupled with the above prepared acid (77 mg, 0.33 mmol) under standard coupling conditions in a manner analogous to that described previously, such as example 2, step A, to provide after flash chromatography (5% CH₃OH/CHCl₃), 227 mg (91%) of the title compound as a white powder: mp 218-220°C; IR (KBr) v_max 3287, 1674, 1663, 1636, 1557, 1539, 1514, 1244, 1115 cm^-1; ¹H NMR (CDCI₃ + DMSO-d₆) δ 9.05 (d, 1 H, J = 1.8 Hz), 8.29 (dd, 1 H, J = 8.1, 2.1 Hz), 8.03 (d, 1 H, J = 9.3 Hz) 7.70 (d, 1 H, J = 8.4 Hz), 7.46 (d, 1 H, J = 8.4 Hz), 7.37-7.22 (m, 11 H), 7.09 (d, 2 H, J = 8.1 Hz), 6.67 (d, 2 H, J = 8.4 Hz), 5.89-5.85 (m, 1 H), 4.88 (d, 1 H, J = 11.7 Hz), 4.83(d, 1 H, J = 11.7 Hz), 4.54 (d, 1 H, J = 12.0 Hz), 4.47 (d, 1 H, J = 12.0 Hz), 4.45-4.35 (m, 1 H), 4.31 (t, 1 H, J = 9.0 Hz), 4.24-4.13 (m, 1 H), 3.92-3.82 (m, 1 H), 3.77 (s, 4 H), 3.64-3.48 (m, 6 H), 3.08-3.02 (m, 1 H), 2.76 (dd, 1 H, J = 14.4, 10.5 Hz), 2.15-1.92 (m, 2 H), 0.94 (d, 6 H, J = 6.9 Hz), 0.88 (d, 6 H, J = 6.6 Hz); ¹⁹F NMR (CHCl₃ + DMSO-d₆) δ -109.78 (d, J = 256 Hz), -122.05 (dd, J = 256, 19 Hz); mass spectrum, m/z 872 (M⁺ + 29), 844 (M⁺ + 1), 509 (100), 418, 318, 290, 219. Anal. Calcd for C₄₆H₅₅F₂N₅O₈: C, 65.47; H, 6.57; N, 8.30. Found: C, 65.07; H, 6.65; N, 9.12.

Step C

Preparation of final title compound.

Reaction Scheme D, step (d): The above prepared alcohol (196 mg, 0.232 mmol) is oxidized under under Swern conditions in a manner analogous to that described

previously in example 1, to provide 196 mg (100%) of crude final title compound as an orange oil after flash

chromatography (3% CH₃OH/CHCl₃). Recrystallization from

CH₂Cl₂/pentane, then CH₂CI₂/ ether, provides 100 mg (51%) of pure final title compound as cream granules: mp 108-135°C; IR (KBr) v_max 3422, 3306, 1638, 1535, 1514, 1454, 1115 cm- ¹ ; ¹H NMR (CDCI₃) δ 8.95-8.87 (m, 1 H), 8.16 and 8.13 and 8.12-8.08 ( 2dd and m, 1 H total, J = 2.2, 1.1 Hz), 7.74 and 7.71 and 7.68-7.67 ( 2dd and m, 1 H total, J = 5.8, 0.7 Hz), 7.43-7.27 (m, 10 H), 7.14-7.04 and 7.13 and 7.09 and 7.06 (m and 3d, 2 H total, J = 8.5, 8.8, 8.8 Hz respectively), 6.95-6.77 and 6.88 and 6.85 (m and 2d, 4H total, J = 8.7 Hz), 6.49 and 6.39 and 6.23 (3d, 1 H total, J = 7.2, 6.7, 9.0 Hz respectively), 5.60-5.56 and 5.46 and 5.33-5.21 (m and bs and m, 1 H total), 5.02 and 4.98 and 4.93 (3s, 2 H total) 4.57-4.40 (m, 3H), 3.81 (bs, 5 H), 3.67-3.59 (m, 5 H), 3.50-3.43 (m, 1H), 3.36-3.27 (m, 1 H), 2.95-2.76 (m, 1 H), 2.17-1.91 (m, 2 H), 0.96-0.88 and 0.83 and 0.82 and 0.71 and 0.59 (m and 4d, 12 H total, J = 6.8 Hz); 19F NMR (CDCI3) d -111.54 (d, J = 270 Hz), -112.47 (A J = 269 Hz), -113.76 (d, J = 270 Hz), -114.62 (d, J = 270 Hz), Hydrate: -114.80 (d, J = 253 Hz), -118.53 (s), -118.68 (s), -122.82 (d, J = 254 Hz); mass spectrum, m/z 870 (M⁺ + 29), 842 (M⁺ + 1), 197, 194, 91 (100); exact mass calcd for C₄₆H₅₄F₂N₅O₈ 842.3940, found 842.3994. Anal. Calcd for C₄₆H₅₃F₂N₅O₈: C, 65.62; H, 6.35; N, 8.32. Found: C, 64.80; H, 6.46; N, 8.27. Example 8

Preparation of 7,7-Difluoro-4,12-bis(1-methylethyl)-6,8,11- trioxo-1-phenyl-9-[[4-(phenylmethoxy)phenyl]methyl]-2-oxa- 5,10,13-triazatetradecan-14-oic Acid, 3-Pyridinylmethyl Ester.

Step A

Preparation of N-[(3-Pyridinylmethoxy)carbonyl]-L-valine.

To a stirred suspension of L-valine methyl ester hydrochloride (2.0 g, 12 mmol) in toluene (15 mL) is added triphosgene (1.78 g, 6 mmol) and DMF (0.15 mL, 2 mmol). The heterogeneous mixture is allowed to stir at room temperature for 30 minutes. To this mixture is added tributylamine (0.1 mL, 0.4 mmol) dropwise over 2 minutes. The reaction mixture is heated to reflux for 1 hour.

Analysis by IR spectroscopy shows a strong signal at 2250 cm^-1, indicating the presence of isocyanate. The now homogeneous solution is cooled to 0°C and 3-pyridylcarbinol (0.9 mL, 9 mmol) is added dropwise over 10 minutes. A white precipitate forms during the addition. The reaction mixture is warmed to room temperature and is allowed to stir for 16 hours. Additional 3-pyridylcarbinol (1.8 mL, 18 mmol) is added and the cloudy mixture is heated to reflux for 3 hours. The solution is concentrated under vacuum, diluted with ethyl acetate and washed with three portions of water. The solution dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum to provide an oil. Flash chromatography (8:1 CH₂CI₂/C₂H₅OH) of the oil provides 1.46 g (60%) of N-[(3- pyridinylmethoxy)carbonyl]-L-valine, methyl ester as a yellow oil: ¹H NMR (CDCI₃) δ 8.61 (s, 1 H), 8.56 (d, 1 H, = 6.5 Hz), 7.71 (d, 1 H, J = 10.2 Hz), 7.29 (dd, 1 H, J = 8.1, 6.6 Hz), 5.38 (bs, 1 H), 5.13 (s, 2 H), 4.29 (dd, 1 H, J = 8.2, 5.9 Hz), 2.12 (m, 1 H), 0.92 (d, 3 H, J = 6.3 Hz), 0.88 (d, 3 H, J = 6.3 Hz); [α]²⁰ _D +9.25° (c 0.85, CHCl₃). Anal. Calcd for C₁₃H₁₈N₂O₄: C, 58.65; H, 6.77; N, 10.53. Found: C, 57.62; H, 7.03; N, 10.47.

Alternatively the N-[(3-pyridinylmethoxy)carbonyl]-L- valine, methyl ester can be prepared as follows: L-valine methyl ester (4.25 g, 34 mmol, freshly prepared from the hydrochloride salt by neutralization with 50% aqueous NaOH) is added to a stirred mixture of 1,1 '-carbonyldiimidazole (4.86 g, 30 mmol) in CH₂CI₂ (30 mL) over 15 minutes. After 15 more minutes, 3-pyridylcarbinol (5.0 mL, 51 mmol) is added dropwise to the homogeneous solution. The

resulting solution is heated at 45°C for 3 hours and then allowed to stir at room temperature overnight. The CH₂CI₂ is removed under vacuum, and the residue is dissolved in toluene (70 mL). The solution is heated at 70°C for 6 hours, and then concentrated under vacuum. The residue is dissolved in CH₂CI₂ and the resulting solution is washed three times with water, dried over anhydrous magnesium sulfate, filtered and concentrate to provide an oil, which is purified by flash chromatography to provide 4.6 g (51%) of the N-[(3-pyridinylmethoxy)carbonyl]-L-valine, methyl ester as a yellow oil. To a stirred solution of the N-[(3- pyridinylmethoxy)carbonyl]-L-valine, methyl ester (1.4 g, 5.3 mmol) in CH₃OH (6 mL) is added LiOH•H₂O (0.24 g, 5.8 mmol). The heterogeneous mixture is allowed to stir at room temperature for 16 hours. The reaction mixture is diluted with water until completely homogeneous, acidified with 0.5 N HCl (11.6 mL, 5.8 mmol) and concentrated under vacuum to provide a white solid, which is crystallized from 8:1 CH₂CI₂/C₂H₅OH to the title compound 0.53 g (40%) as a white crystalline solid: mp 242-244°C; ¹H NMR (DMSO-d₆) δ 8.9 (m, 2 H), 8.5 (d, 1 H, J = 8 Hz), 8.05 (m, 1 H), 7.7 (d, 1 H, J = 9 Hz), 5.22 (s, 2 H), 3.9 (m, 1 H), 2.05 (m, 1 H), 0.85 (m, 6 H). Step B

Preparation of [1 (R), 3ξ, 4(S)]-2,4,5-Trideoxy-2,2- difluoro-4-[[3-methyl-1-oxo-2-[[(3- pyridinylmethoxy)carbonyl]amino]butyl]amino]-N-[2-methyl-1- [(phenylmethoxy)methyl]propyl]-5-[4-(phenyl- methoxy)phenyl3-L-glycero-pentanamide.

The amino alcohol prepared in example 5, step D (0.28 g, 0.53 mmol) is coupled with the above prepared acid (0.19 g, 0.74 mmol) under standard coupling conditions described previously, such as example 2, step A to provide, after crystallization from ethyl acetate, 0.20 g (50%) of title compound as a white powder: mp 187-191°C; IR (KBr) v_max 3426, 3300, 2960, 1698, 1674, 1657, 1541, 1512, 1246, 1177, 1151, 1105, 1028, 698 cm^-1; ¹H NMR (DMSO-d₆) δ 8.58 (d, 1 H, J = 1.6 Hz), 8.49 (dd, 1 H, J = 4.7, 1.4 Hz), 7.76 (d, 1 H, J = 7.9 Hz), 7.46-7.24 (m, 13 H), 7.13-7.07 (2d, 2 H total, J = 8.8 Hz), 6.88 and 6.81 (2d, 2 H total, J = 8.8, 8.3 Hz), 8.34, 7.97, and 6.18 (3d, 1 H total), 5.08 and 5.03 (d and s, 2 H total, J = 5.7 Hz), 4.99 (d, 2 H, J = 2.2 Hz), 4.46 (d, 2 H, J = 3.8 Hz), 4.21 (m, 1 H), 4.06-3.92 (m, 1 H), 3.87-3.73 (m, 2 H), 3.52 (d, 2 H, J = 6.9 Hz), 2.93 (d, 1 H, J = 12.2 Hz), 2.6 (m, 1 H), 1.93-1.75 (m, 2 H), 0.87 (apparent t, 8 H, J = 6.6 Hz), 0.68 (dd, 4 H, J = 6.8, 6.6 Hz); ¹⁹F NMR (DMSO-d₆) δ major diastereomer: -108.9 (dd,J = 251, 7 Hz), -119.8 (dd, J = 245, 19 Hz), minor

diastereomer: -111.6 (dd, J = 252, 8 Hz), -117.1 (dd, J = 250, 18 Hz); mass spectrum, m/z 761 (M⁺ + 1), 555, 138, 121, 110, 92. Anal. Calcd for C₄₂H₅₀F₂N₄O₇: C, 66.32; H, 6.58; N, 7.37. Found: C, 62.43; H, 6.36; N, 6.79.

Step C

Preparation of final title compound.

Reaction Scheme D, step (d): In a manner analogous to that described previously in example 1, the above prepared alcohol is oxidized under Swern conditions to provide after flash chromatography (8:1 CH₂CI₂/C₂H₅OH), 100 mg (50%) of final title compound as a white powder: mp 108-111°C; IR (KBr) v_max 3416, 3308, 2963, 1696, 1660, 1537, 1514, 1246, 1115, 1028 cm^-1; ¹H NMR (DMSO-d₆) δ 8.91 (d, 1 H, J = 8.8 Hz), 8.58-8.51 (m, 2 H), 7.75 (d, 1 H, J = 7.7 Hz), 7.45- 7.23 (m, 12 H), 7.16 (d, 1 H, J = 8.6 Hz), 6.90(d, 2 H, J = 8.6 Hz), 5.06-4.99 (m, 5 H), 4.45 (d, 2 H, J = 3.1 Hz), 3.92-3.8 (m, 2 H), 3.52 (m, 2 H), 3.10 (dd, 1 H, J = 14.

3.1 Hz), 2.69 (dd, 1 H, J = 14.1, 9.9 Hz), 1.87 (m, 2 H), 0.84 and 0.78 (2dd, 10 H total, J = 10.8, 7.1 Hz and J = 6.4, 4.8 Hz respectively), 0.60 (dd, 2 H, J = 8.7, 6.9 Hz), ¹³C NMR (DMSO-d₆) δ 171.2 157.15, 155.8, 149.0, 148.95, 148.9, 138.3, 137.1, 135.5, 132.6, 130.2, 130.07, 128.8, 128.7, 128.37, 128.16, 127.75, 127.67, 127.6, 127.5,

127.44, 127.36, 123.43, 114.5, 71.9, 69.5, 69.45, 69.1, 69.0, 63.16, 59.6, 55.25, 54.76, 54.67, 33.8, 33.75, 30.35 , 28.8, 28.77, 19.4, 19.33, 18.98, 18.59, 17.86; ¹⁹F NMR

(DMSO-d₆) δ -111.36 (d, J = 272 Hz), -114.36 (d, J = 270 Hz), -112.96 (s), -117.06 (d, J = 255 Hz), -120.00 (d, J = 250 Hz); mass spectrum, m/z 759 (M⁺ + 1), 460, 110, 91.

Anal. Calcd for C₄₂H₄₈F₂N₄O₇•H₂O: C, 64.94; H, 6.44; N, 7.22. Found: C, 64.70; H, 6.36; N, 7.24. Example 9

Preparation of [1R-(1R*,2S*)3-α,α-Difluoro-γ-[[3-methyl-2- [[4-(4-morpholinylsulfonyl)benzoyl]amino]-1- oxobutyl]amino]-N-[2-methyl-1- [(phenylmethoxy)methyl]propyl]-8-oxo-4-(phenylmethoxy)- benzenepentanamide.

Step A

Preparation of [1 (R),3ξ, 4(S)]-2,4,5-Trideoxy-2,2- difluoro-4-[[3-methyl-2-[[4-(4- morpholinylsulfonypbenzoyl]amino]-1-oxobutyl]-amino]-N-[2- methyl-1-[(phenylmethoxy)methyl]propyl]-5-[4-(phenylmethoxy)phenyl]-L-glycero-pentanamide.

Reaction Scheme D, step (c): The (S)-amino alcohol prepared in example 5, step D (161 mg, 0.26 mmol) is coupled with the acid (77 mg, 0.28 mmol) of the following structure

[prepared as described by Sycheva, T.P. et al., Sbornik Statei Obshchei Khim, Akad. Nauk S.S.S.R., 1, 568-571

(1953)] under standard coupling conditions in a manner analogous to that described previously, such as example 2, step A, to provide after flash chromatography (1:1 ethyl acetate/CH₂Cl₂), 140 mg (62%) of the title compound as a white solid. Recrystallization from ethyl

acetate/cyclohexane provides the title compound as a white powder: mp 172.5-190.5°C (172.5-174, then 189.5-190.5°C); IR (KBr) v_max 3420, 3322, 2965, 1643, 1534, 1514, 1171, 1113 cm^-1; ¹H NMR (CHCl₃) δ 7.90 (d, 2 H, J = 8.4 Hz), 7.79 (d,

2 H, J = 8.3 Hz), 7.4-7.25 (m, 10 H), 7.08 (d, 2 H, J = 8.6 Hz), 6.78 (d overlapping m, 4 H, J = 8.5 Hz), 6.65 (d, 1 H, J = 8.6 Hz), 4.93 (s, 2 H), 4.53 (d, 1 H, J = 12.0 Hz), 4.47 (d, 1 H, J = 12.0 Hz), 4.45-4.24 (m, 4 H), 3.82 (m, 1 H), 3.73-3.65 (nm, 4 H), 3.62 (dd, 1 H, J = 9.7, 4.1 Hz), 3.46 (dd, 1 H, J = 10.0, 3.9 Hz), 3.1-2.85 (m, 6 H), 2.12 (m, 1 H), 1.98 (m, 1 H), 0.97-0.89 (m, 12 H); ¹⁹F NMR

(CDCI₃) δ -110.18 (dd, J = 261, 4 Hz), -121.09 (dd, J = 261, 18 Hz); mass spectrum, m/z 879 (M⁺ + 1, 100), 527, 325, 254. Anal. Calcd for C₄₆H₅₆F₂N₄O₉S: C, 62.85; H, 6.42; N, 6.37. Found: C, 62.65; H, 6.43; N, 6.26. Step B

Preparation of final title compound.

Reaction Scheme D, step (d): In a manner analogous to that described in example 1 the above prepared alcohol (133 mg, 0.151 mmol) is oxidized under Swern conditions to provide 82 mg of a mixture of diastereomers of final title compound after flash chromatography (3:2 ethyl

acetate/cyclohexane). The mixture partially crystallizes from cyclohexane/ethyl acetate upon evaporation of the solvent. The tacky pale yellow solid is triturated with ether to provide 59 mg (44%) of a single diastereomer of final title compound as a white powder: mp 114-116°C; IR (KBr) v_max 3426, 2971, 1686, 1663, 1512, 1171, 1115 cm^-1; ¹H NMR (CDCI₃) δ 7.92 (d, 2 H, J = 8.3 Hz), 7.81 (d, 2 H, = 8.3 Hz), 7.41-7.29 (m, 10 H), 7.06 (d, 2 H, J = 8.6 Hz), 6.85 (d, 2 H, J = 8.6 Hz), 6.78 (d, 2 H, J = 8.6 Hz), 6.29 (d, 1 H, J = 6.7 Hz), 5.26 (m, 1 H), 4.99 (s, 2 H, major peak), 4.55 (d, 1 H, J = 12.0 Hz), 4.48 (d, 1 H, J = 12.0 Hz), 4.43 (dd, 1 H, J = 8.4, 6.4 Hz), 3.84 (m, 1 H), 3.72 (narrow m, 4 H), 3.63 (dd, 1 H, J = 9.8, 3.8 Hz), 3.47 (dd, 1 H, J = 9.7, 3.8 Hz), 3.31 (dd, 1 H, J = 14.4, 5.0 Hz), 3.00-2.87 (m, 5 H), 2.14 (m, 1 H), 2.00 (m, 1 H), 0.96 (d,

3 H, J = 6.7 Hz), 0.95 (d, 3 H, J = 6.7 Hz), 0.94 (d, 3 H, J = 6.7 Hz), 0.92 (d, 3 H, J = 6.7 Hz); ¹⁹F NMR (CDCI₃) d - 112.45 (d, J = 270 Hz), -113.69 (d, J = 270 Hz), -117.94 (d, J = 255 Hz), -119.29 (d, J = 255 Hz); mass spectrum (CI), m/z 905 (M⁺ + 29), 877 (M⁺ + 1), 525, 507, 401, 353 (100), 197, 107. Anal. Calcd for C₄₆H₅₄F₂N₄O₉S•0.5 H₂O: C, 62.36; H, 6.26; N, 6.32. Found: C, 62.24; H, 6.30; N, 6.27.

Example 10

Preparation of [1R-(1R*,2S*)]-α,α-Difluoro-γ-[[3-methyl-2- [[4-(4-morpholinylcarbonyl)benzoyl]amino]-1- oxobutyl]amino]-N-[2-methyl-1-

[(phenylmethoxy)methyl]propyl]-β-oxo-4-(phenylmethoxy)- benzenepentanamide .

Step A

Preparation of [1 (R), 3ξ, 4(S)]-2,4,5-Trideoxy-2,2- difluoro-4-[[3-methyl-2-[[4-(4- morpholinylcarbonypbenzoyl]amino]-1-oxobutyl]-aminol-N-[2- methyl-1-[(phenylmethoxy)methyl3propyl]-5-[4-(phenylmethoxy)phenyl]-L-glycero-pentanamide.

Reaction Scheme D, step (c): The (R) amino alcohol (171 mg, 0.274 mmol) prepared in example 5, step D is coupled with 4-(4-morpholinylcarbonyl Jbenzoic acid (68 mg, 0.29 mmol, prepared in example 10a) under standard coupling conditions, such as example 2, step A, in a manner

analogous to that described previously to provide, after flash chromatography (3% CH₃OH/CHCl₃), 217 mg (94%) of the title compound as a yellow powder: IR (KBr) v_max 3428, 3322, 1636, 1534, 1512, 1456, 1279, 1258, 1244, 1115 cm^-1; ¹⁹F NMR (CDCI₃) δ -110.19 (d, J = 259 Hz), -117.26 (d, J = 259 Hz), -120.14 (d, J = 259 Hz), -121.40 (dd, J = 259, 20 Hz) + impurities; mass spectrum, m/z 871 (M⁺ + 29), 843 (M⁺ + 1), 527, 509, 329, 317 (100), 289, 250, 218.

Step B

Preparation of final title compound.

Reaction Scheme D, step (d): The above prepared alcohol is oxidized under Swern conditions as follows: To a stirred solution of the above prepared alcohol (215 mg, 0.255 mmol) in anhydrous CH₂CI₂ (3 mL) and anhydrous DMSO (0.36 mL, 5.1 mmol) at -45°C is added 2 M oxalyl

chloride/CH₂Cl₂ (1.0 mL) over 5 minutes. The solution is allowed to stir at -40 to -30°C for 2.5 hours. The solution is then cooled to -70°C and diisopropylethylamine (0.67 mL, 3.8 mmol) is added over 5 minutes. The solution is allowed to warm to room temperature, diluted with CH₂CI₂, washed twice with water, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum. The residue is purified by flash chromatography (3% CH₃OH/CHCl₃) to provide 210 mg (98%) of final title compound as an amber oil.

Recrystallization from CH₂Cl₂/pentane provides 80 mg (37%) of final title compound as an amber powder: mp 87-92°C; IR (KBr) v_raax 3306, 1636, 1534, 1514, 1454, 1279, 1258, 1244, 1115 cm^-1; ¹H NMR (CDCI₃) δ 7.82-7.75 (m, 2 H), 7.48-7.30 (m, 12 H), 7.11-7.04 (m, 2 H), 6.91-6.82 (m, 2 H), 6.78 (d, 1 H, J = 8.7 Hz), 6.68(d, 1 H, J = 8.7 Hz), 6.44 and 6.33 (2d, 1 H, J = 6.9 Hz), 5.31-5.22 (m, 1 H), 5.05-4.94 (m, 2 H), 4.57-4.38 (m, 3 H), 3.88-3.28 (m, 12 H), 2.94-2.81 (m, 1 H), 2.16-1.93 (m, 2 H), 0.96-0.58 (m, 12 H); ¹⁹F NMR (CDCI₃) δ -111.56 (d, J = 270 Hz), -112.56 (d, J = 270 Hz), -113.63 (d, J = 270 Hz), -114.54 (d, J = 270 Hz), Hydrate: -113.53 (d, J = 292 Hz), -114.85 (d, J = 252 Hz), -118.71 (d, J = 292 Hz), -122.88 (d, J = 252 Hz); mass spectrum, m/z 869 (M⁺ + 29), 841 (M⁺ + 1), 525, 317, 279, 218, 197, 157 (100); exact mass calcd for C₄₇H₅₅F₂N₄O₈ 841.3988, found 841.4043. Anal. Calcd for C₄₇H₅₄F₂N₄O₈: C, 67.13; H, 6.47; N, 6.66. Found: C, 65.80; H, 6.60; N, 6.69. Example 10a

Preparation of 4-(4-morpholinylcarbonypbenzoic acid.

Preparation of 4-(4-morpholinylcarbonyl)benzoic acid methyl ester.

To a stirred suspension of monomethyl terephthalate (25.0 g, 0.14 mmol) in methylene chloride (500 mL) and dimethylformamide (4 mL) is added dropwise oxalyl chloride (12.1 mL, 0.14 mol) with vigorous gas evolution. After gas evolutions ceases, the reaction is stirred for 45 minutes and then cooled in an ice-water bath. Morpholine (48.4 mL, 0.56 mol) is then added resulting in an exotherm. After the addition is complete the reaction is allowed to warm to room temperature and stirred for 1 hour. The reaction mixture is then washed with 0.5 N HCl (2 x 500 mL), half- saturated sodium bicarbonate (2 x 500 mL), water (2 x 500 mL) and brine (300 mL). The reaction is dried over

anhydrous magnesium sulfate, filtered and concentrated under vacuum to provide the title compound (33.8 g, 98%) as a white solid; mp 74-76°C.

Preparation of final title compound.

to a stirred solution of the above ester (50.1 g, 0.20 mmol) in methanol (800 mL) is added 1N lithium hydroxide (241 mL, 0.24 mol) followed by water (160 mL). After stirring at room temperature for 7 hours, additional water (100 mL) is added. The reaction is then stirred an

additional 24 hours and then concentrated to remove the methanol. The aqueous is extracted with methylene chloride (2 x 100 mL) and diethyl ether (200 mL). The aqueous layer was then cooled in an ice-water bath and acidified to pH 1 with 12 N HCl (ca. 20 mL). Filtration provides crude white solid. The solid material is suspended in methylene chloride (2 L) and heated to reflux. It is then cooled to room temperature, treated with anhydrous magnesium sulfate, and filtered. The filtrate is concentrated under vacuum to provide the final title compound (42.2 g, 89%) as a white solid; mp 194-196°C.

Example 11

Preparation of N-[1-[[[3,3-Difluoro-4-[[2-methyl-1- [(phenylmethoxy)methyl]-propyl]amino]-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]-methyl]butyl]amino]carbonyl]-2- methylpropyl]-4-morpholineacetamide .

Step A

Preparation off 1 (R), 3ξ, 4(S)]-2,4,5-Trideoxy-2,2- difluoro-4-[[3-methyl-2-[[(4-morpholinypacetyl]amino]-1- oxobutyl]amino]-N-[2-methyl-1-

[(phenylmethoxy)methyl]propyl]-5-[4-(phenylmethoxy)phenyl]-

L-glycero-pentanamide .

Reaction Scheme D, step (c): The (R,S)-amino alcohols (201 mg, 0.321 mmol) prepared in example 5, step D are coupled with 4-morpholine acetic acid, trifluoro acid salt (92 mg, 0.35 mmol, compound (A) prepared in example 5a) under standard coupling conditions in a manner analogous to that described previously [with the addition of 1.1 eq. of NMM] to provide after flash chromatography (4% CH₃OH/CHCl₃), 224 mg (92%) of title compound as a beige powder: mp 110- 117°C; IR (KBr) v_max 3298, 2963, 1674, 1649, 1545, 1512, 1238, 1115, 698 cm^-1; ¹⁹F NMR (CDCI₃) δ major diastereomer- 110.56 (dd, J = 260, 5 Hz), -120.79 (dd, J = 260, 18 Hz); mass spectrum, m/z 781 (M⁺ + 29), 753 (M⁺ + 1, 100), 752 (M⁺), 291, 100, 91.

Step B

Preparation of final title compound.

Reaction Scheme D, step (d): In a manner analogous to that described in example 1 the above prepared alcohol (206 mg, 0.274 mmol) is oxidized under Swern conditions to provide 170 mg (83%) of an orange glass after flash chromatography (3% CH₃OH/CHCl₃). Recrystallization from CH₂Cl₂/ether provides 70 mg (34%) of final title compound as sticky amber crystals: mp 48-53°C; IR (CHCl₃) v_max 2969, 1686, 1512, 1242, 1117, 760, 750, 731 cm^-1; ¹H NMR (CDCI₃) δ 7.55-7.50 (m, 1 H), 7.43-7.29 (m, 10 H), 7.14-7.07 (m, 2 H), 6.92-6.78 (m, 3 H), 6.52-6.49 and 6.40-6.37 (2m, 1 H total), 5.33-5.19 (m, 1 H), 5.03 (apparent d, J = 3.6 Hz), 4.55 (d, 1 H, J = 11.9 Hz), 4.48 and 4.47 (2d, 1 H total, = 11.9 Hz), 3.88-3.80 (m, 1 H), 3.74-3.61 (m, 5 H), 3.50- 3.44 (m, 1 H), 3.32-3.25 (m, 1 H), 2.99-2.81 (m, 3 H), 2.49-2.46 (m, 4 H), 2.14-1.95 (m, 2 H), 1.28-1.24 and 0.95- 0.70 and 0.50 (2m and d, 12 H total, J = 6.7 Hz); ¹⁹F NMR (CDCI₃) δ -111.32 (d, J = 273 Hz), -112.96 (s), -114.64 (d, J = 272 Hz); mass spectrum, m/z 779 (M⁺ + 29), 751 (M⁺ + 1), 226, 100 (100), 86; exact mass calcd for C₄₁H₅₃F₂N₄O₇ 751.3882, found 751.3892. Anal. Calcd for

C₄₁H₅₂F₂N₄O₇•1.3H₂O: C, 63.60; H, 6.77; N, 7.24. Found: C, 63.64; H, 6.80; N, 6.84.

Example 12

Preparation of N-[1-[[[3,3-Difluoro-4-[[2-methyl-1- [(phenylmethoxy)methyl]-propyl]amino3-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]methyl]-butyl]amino]carbonyl]-2- methylpropyl]-1H-imidazole-1-acetamide.

.OBn

U

Step A

Preparation of 1H-Imidazole-1-acetic Acid•HCl.

To a stirred solution of imidazole (1.50 g, 22.0 mmol) in CH₂CI₂ (25 mL) at 0°C under nitrogen is added dropwise tert-butyl bromoacetate (1.62 mL, 10.0 mmol). The ice bath is removed and the solution is allowed to stir at room temperature for 22 hours. The solution is concentrated under vacuum and the residue is partitioned between ethyl acetate/ water. The organic layer is washed with water and concentrated under vacuum to provide 1.22 g (67%) of tert- butyl 1H-imidazole-1-acetate as a white crystalline solid: mp 110-113°C; ¹H NMR (CHCl₃) δ 7.49 (s, 1 H), 6.95 (s, 1 H), 4.59 (s, 2 H), 1.47 (s, 9 H) . HCl gas was bubbled through a solution of the tert-butyl 1H-imidazole-1-acetate in CH₃NO₂ (4-5 mL) for 20-25 minutes. After standing for 20 minutes more, the solution is concentrated under vacuum and recrystallized from CH₃CN/CH₃OH to provide the title compound in 70% yield: mp 206-209°C; ¹H NMR (DMSO-d₆) δ 9.12(d, 1 H, J = 1.4 Hz), 7.73 (narrow m, 1 H), 7.68 (d, 1 H, J = 1.4 Hz), 5.15 (s, 2 H). Anal. Calcd for

C₅H₆N₂O₂•HHCl: C, 36.94; H, 4.34; N, 17.23. Found: C,

37.21; H, 4.36; N, 17.39.

Step B

Preparation of [1 (R), 3ξ, 4(S)]-2,4,5-Trideoxy-2,2- difluoro-4-[[2-[(1H-imidazol-1-ylacetyl)amino3-3-methyl-1- oxobutyl]amino3-N-[2-methyl-1-

[(phenylmethoxy)methyl]propyl3-5-[4-(phenylmethoxy)phenyl]- L-glycero-pentanamide.

Reaction Scheme D, step (c): To a solution of the (R)- amino alcohol (205 mg, 0.328 mmol) prepared in example 5, step D in anhydrous CH₂CI₂ (4 mL) and anhydrous DMF (7 mL) is added 1H-imidazole-1-acetic acid•HCl(56 mg, 0.34 mmol) prepared above and NMM (35 μL, 0.32 mmol). Not all of the 1H-imidazole-1-acetic acid dissolves. HOBT (53 mg, 0.34 mmol) and EDC (66 mg, 0.34 mmol) are then added and the resulting mixture is allowed to stir overnight at room temperature. The mixture is concentrated under vacuum and the residue is dissolved in ethyl acetate. The organic layer is washed with water, 10% aqueous sodium bicarbonate, brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum to provide yellow solids which contain two major spots by TLC (10% CH₃OH/CHCl₃). The two compounds are separated by chromatography (the first is eluted with 4% CH₃OH/CHCl₃, the second with 1:1

CH₃OH/CHCl₃). The less polar material is the formamide of of the starting material while the more polar material is the title compound (110 mg, 45%) which is isolated as a white powder: mp 190-193°C; IR (KBr) v_max 3430, 3297, 1678, 1647, 1549, 1512, 1240, 1082 cm^-1; ¹⁹F NMR (CDCI₃ + DMSO-d6) δ major diastereomer -115.66 (dd, J = 259, 7 Hz), -120.48 (dd, J = 259, 18 Hz); mass spectrum, m/z 762(M⁺ + 29), 734 (M⁺ + 1), 91 (100).

Step C

Preparation of final title compound.

Reaction Scheme D, step (d): In a manner analogous to

101 that described in example 1 the above prepared alcohol ( mg, 0.138 mmol) is oxidized under Swern conditions to provide 101 mg (100%) of an orange oil after flash

chromatography (2:1 CHCl₃/CH₃OH). Recrystallization from CH₂Cl₂/pentane provides 50 mg (50%) of final title compound as a beige solid: mp 112-116°C; IR (KBr) v_max 3428, 3295, 2963, 1647, 1551, 1512, 1240, 1113, 698 cm^-1; ¹H NMR (DMSO- d₆) δ 9.00 and 8.93 and 8.66 and 8.64 (4d, 1 H total, J = 9.0, 9.0, 7.2, 7.2 Hz respectively), 8.16 (apparent

triplet, 1 H, J = 8.4 Hz), 7.59 (bs, 1 H), 7.46-7.26 (m, 11 H), 7.15 and 7.14 (2d, 1 H total, J = 8.6 Hz), 7.06 (bs, 1 H), 6.90 and 6.89 (apparent 2d, 3 H, J = 8.7 Hz), 5.05 (s, 2 H), 5.01 (dd, 1 H, J = 7.5, 3.4 Hz), 4.79-4.61 (m, 2 H), 4.50-4.39 (m, 2 H), 4.30-4.20 (m, 1 H), 3.85-3.76 (m, 1 H), 3.54-3.50 (m, 2 H), 3.20-3.08 (m, 1 H), 2.72-2.57 (m, 1 H), 2.00-1.72 (m, 2 H), 1.27-1.21 and 0.87-0.69 and 0.61-0.52 (m, 12 H total); ¹⁹F NMR (DMSO-d₆) δ -108.87 (d, J = 267 Hz), -109.82 (d, J = 268 Hz), -111.37 (d, J = 268 Hz), - 112.32 (d, J = 254 Hz), 112.58 (d, J = 268 Hz), -117.61 (d, J = 254 Hz); mass spectrum, m/z 760 (M⁺ + 29), 732 (M⁺ +

1), 712, 180, 91 (100), 69; exact mass calcd for C₄₀H₄₈F₂N₅O₅ 732.3573, found 732.3541. Anal. Calcd for C₄₀H₄₇F₂N₅O₆•2H₂O: C, 62.57; H, 6.69; N, 9.12. Found: C, 62.07; H, 6.49; N, 9.05.

Example 13

Preparation of [1-[[[3,3-Difluoro-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]-methyl]-4-[(2- pyridinylmethyl)amino]butyl]amino]carbonyl]- 2- methylpropyl]-carbamic Acid, 3-Pyridinylmethyl Ester.

Step A

Preparation of [1 (R), 3ξ]-2,4,5-Trideoxy-4-[[(1,1- dimethylethoxy)carbonyl]-amino3-2,2-difluoro-5-[4-

(phenylmethoxy) -phenyl]-N-(2-pyridinylmethyl)-L-glycero- pentanamide.

Reaction Scheme A, step (b): To a stirred solution of 4-tert-butoxycarbonylamino-2,2-difluoro-3-hydroxy-5-(4- benzyloxy)phenylpentanoic acid, ethyl ester (1.5 g, 3.1 mmol) prepared in example 1 step B, in dry THF (16 mL) is added 2-(aminomethyl)pyridine (0.38 mL, 3.8 mmol). The homogeneous solution is heated at reflux for 4 hours and then allowed to cool to room temperature. A thick white precipitate forms upon cooling which is filtered and washed with ether to provide 0.80 g (48%) of title compound as a white powder: mp 166-170°C; ¹H NMR (DMSO-d₆) δ 9.23 (bs, 1 H), 8.51 (m, 1 H), 7.78 (t, 1 H, J = 7.5 Hz), 7.5-7.25 (m, 8 H), 7.12 (d, 2 H, J = 8.4 Hz), 6.91 (d, 2 H, J = 8.4 Hz), 6.69 (d, 1 H, J = 10.4 Hz), 6.19 (d, 1 H, J = 8.9 Hz), 5.08 (s, 2 H), 4.58-4.32 (m, 2 H), 4.15-3.91 (m, 1 H), 3.82 (m, 1 H), 2.95 (d, 1 H, J = 10.9 Hz), 1.15 (s, 9 H); ¹⁹F NMR (DMSO-d₆) δ major diastereomer: -103.30 (dd, J = 253, 9 Hz), -117.67 (dd, J = 252, 17 Hz), minor diastereomer: -111.37 (dd, J = 254, 8 Hz), -121.27 (dd, J = 256, 18 Hz).

Step B

Preparation of [3ξ, 4(S)]-2,4,5-Trideoxy-2,2-difluoro-4- [[3-methyl-1-oxo-2-[[(3- pyridinylmethoxy)carbonyl]amino]butyl]amino]-5-[4- (phenylmethoxy)phenyl]-N-(2-pyridinylmethyp-L-glycero- pentanamide.

Reaction Schemes A and A', steps (d) and (e): The above prepared amide (0.2 g, 0.4 mmol) is deprotected in a manner analogous to that described previously in example 5, step B by treatment with HCO₂H. The free amine is then coupled with N-[(3-Pyridinylmethoxy)carbonyl]-L-valine (0.38 g, 1.5 mmol), prepared in example 8, under standard coupling conditions in a manner analogous to that described previously to provide after recrystallization from ethyl acetate, 0.09 g (40%) of title compound as a white powder: mp 201-210°C; ¹H NMR (DMSO-d₆) δ 9.48 (bs, 1 H), 8.79 (m, 1 H), 8.65 (m, 2 H), 8.02-7.85 (m, 3 H), 7.39-7.65 (m, 9 H), 7.24 (d, 2 H, J = 8.5 Hz), 6.96 (d, 2 H, J = 8.5 Hz), 6.48 (d, 1 H, J = 10.4 Hz), 5.25 (d, 2 H, J = 3.8 Hz), 5.14 (s, 2 H), 4.63-4.55 (m, 2 H), 4.36 (m, 1 H), 4.17 (m, 1 H), 3.91 (dd, 1 H, J = 7.8, 6.0 Hz) 3.14-3.03 (m, 1 H), 2.81- 2.55 (m, 1 H), 1.95 (m, 1 H), 0.81 (dd, 6 H, J = 9.1, 7.0 Hz); ¹⁹F NMR (DMSO-d₆) δ -110.17 (dd, J = 254, 11 Hz), - 119.79 (dd, J = 247, 16 Hz).

Step C

Preparation of final title compound.

Reaction Scheme A', step (f): The above prepared alcohol (0.08 g, 0.1 mmol) is oxidized under Swern

conditions in an analogous manner to that described previously, such as example 1, step G, from 2 M oxalyl chloride/CH₂Cl₂ (0.6 mL, 1 mmol), DMSO (0.19 mL, 2.6 mmol), and diisopropylethylamine (0.41 mL, 2.4 mmol), 0.04 g (50%) to provide the final title compound as a tan powder: mp 90- 95°C; IR (KBr) v_max 3401, 3306, 1699, 1599, 1437, 1298, 1242, 1178, 1113, 1026 cm^-1; ¹H NMR (CHCl₃) δ 8.63-8.52 (m, 2 H), 8.42 and 8.19, and 8.05 (3m, 2 H total), 7.77-7.62 (m, 2 H), 7.46-7.22 (m, 9 H), 7.18 (t, 1 H, J = 5.5 Hz), 7.05 (d, 2 H, J = 8.2 Hz), 6.89 (d, 2 H, J = 8.2 Hz), 5.35 and 5.22 (2d, 1 H total, J = 8.5 Hz), 5.10 (s, 2 H), 5.05 (s, 2 H), 4.87-4.66 (m, 1 H), 4.60-4.48 (m, 1 H), 3.81 (dd, 1 H, J = 9.2, 6.7 Hz), 3.32 and 3.27 (2d, 1 H total, J = 5.2 and 4.8 Hz), 3.18 and 3.13 (2d, 1 H total, J = 9.2 and 8.4 Hz) 1.91 (m, 1 H), 1.31 (d, 1 H, J = 6.8 Hz), 0.73 and 0.78 and 0.82 (3d, 5 H total, J = 6.8 Hz); ¹⁹F NMR (CDCI₃) δ -110.48 (d, J = 276 Hz), -113.38 (s), -113.51 (d, J = 276 Hz), Hydrate: -118.75 (d, J = 254 Hz), -120.75 (d, J = 255 Hz); mass spectrum, m/z 674 (M⁺ + 1), 460, 348, 280, 272, 252, 207, 138, 110 (100), 92.

Example 14

Preparation of [1-[[[3,3-Difluoro-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]-methyl]-4-[(3- pyridinylmethyl)amino]butyl]amino]carbonyl]-2- methylpropyl]-carbamic Acid, 3-Pyridinylmethyl Ester.

Step A

Preparation of [1 (R), 3ξ]-2,4,5-Trideoxy-4-[[(1,1- dimethylethoxy)carbonyl]-amino3-2,2-difluoro-5-[4-

(phenylmethoxy)-phenyl]-N-(3-pyridinylmethyp-L-glycero- pentanamide.

Reaction Scheme A, step (b): The title compound is prepared in a manner analogous to that described in example 13, step A from 4-tert-butoxycarbonylamino-2,2-difluoro-3- hydroxy-5-(4-benzyloxy)phenylpentanoic acid, ethyl ester (1.5 g, 3.1 mmol) prepared in example 1 step B, and

3-(aminomethyl)pyridine (0.38 mL, 3.8 mmol). The

precipitated solids are washed with ether and are

recrystallized from ethyl acetate to provide 0.80g (45%) of title compound as a white powder: mp 158-160°C; ), NMR

(CHCl₃) δ 8.55 (bs, 2 H), 7.7 (d, 1 H, J = 7.2 Hz), 7.5-7.2 (m, 8 H), 7.1 (d, 2 H, J = 8.4 Hz), 6.9 (d, 2 H, J = 8.3 Hz), 5.0 (s, 2 H), 4.9 (d, 1 H, J = 9.8 Hz), 4.5 (d, 2 H, J = 2.6 Hz), 4.1-3.9 (m, 2 H), 3.0-2.8 (m, 2 H), 1.4 (s, 9 H); ¹⁹F NMR (DMSO-d₆) δ -110.84 (d, J = 272 Hz), -122.56 (dd, J = 273, 21 Hz); mass spectrum, m/z 542 (M⁺ + 1), 486, 442, 424, 344, 244, 224, 197, 109, 91. Step B

Preparation of [3ξ,4(S)]-2,4,5-Trideoxy-2,2-difluoro-4-[[3- methyl-1-oxo-2-[[(3- pyridinylmethoxy)carbonyl]amino]butyl]amino3-5-[4-(phenylmethoxy)phenyl]-N-(3-pyridinylmethyl)-L-glycero- pentanamide.

Reaction Schemes A and A', steps (d) and (e): The above prepared amide (0.27 g, 0.49 mmol) is treated with 97% HCO₂H. The reaction mixture became homogeneous within 5 minutes. The solution is allowed to stir at room

temperature for 3 hours. It is then concentrated under vacuum. The yellow oil is then dissolved in ethyl acetate, washed twice with aqueous 1 N sodium bicarbonate, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum to provide the corresponding free amine as a yellow solid (0.18 g, 0.41 mmol). This is dissolved in a 1:1 mixture of CH₂CI₂/ DMF (6 mL). To this stirring

solution at room temperature is added HOBT (0.07 g, 0.5 mmol), NMM (0.05 mL, 0.5 mmol), N-[(3- pyridinylmethoxy)carbonyl]-L-valine (0.13 g, 0.52 mmol), prepared in example 8 , and EDC (0.1 g, 0.5 mmol) in that order. After 16 hours, the mixture is diluted with CH₂CI₂ and washed with water. A white precipitate separates, which is filtered, washed several times with ether, and recrystallized from ethyl acetate to provide 0.12 g (45%) of title compound as a white powder: mp 195-196°C; ¹H NMR (DMSO-d₆) δ 8.7-8.4 (m, 4 H), 7.75 (d, 1 H, J = 10.4 Hz), 7.65 (d, 1 H, J = 11.2 Hz), 7.5-7.3 (m 7 H), 7.15 (d, 2 H, J = 8.4 Hz), 6.9 (d, 2 H, J = 8.4 Hz), 5.12 (s, 2 H), 5.08 (s, 2 H), 4.5-4.2 (m, 3 H), 4.1-3.9 (m, 2 H), 2.8-2.6 (m, 2 H), 2.0 (m, 1 H), 0.8 (m, 6 H); ¹⁹F NMR (DMSO-d₆) δ -111.2 (d, J = 257 Hz), -122.05 (dd, J = 250, 20 Hz); mass spectrum, m/z 676 (M⁺ + 1), 567, 424, 150, 138, 110 (100), 92. Anal. Calcd for C₃₆H₃₉F₂N₅O₆: C, 63.31; H, 5.87; N, 10.25. Found: C, 63.07; H, 5.90; N, 10.23.

Step C

Preparation of final title compound.

Reaction Scheme A', step (f): The above prepared alcohol is oxidized under Swern conditions in a manner analogous to example 1 as follows: To a slightly cloudy solution of the above prepared alcohol (0.08 g, 0.12 mmol) in CH₂Cl₂ (2 mL) and DMSO (0.21 mL) at -45°C is added 2M oxalyl chloride/CH₂Cl₂ (0.6 mL, 1 mmol) over 5 minutes. The solution is allowed to stir at -35 to -45°C for 2.5 hours and is then cooled to -78°C. Diisopropylethylamine (0.42 mL, 2.4 mmol) is added over 5 minutes. The solution is allowed to warm to room temperature over 1.5 hours, is diluted with CH₂CI₂ and washed with water. The yellow precipitate which forms is filtered and washed three times with ether to provide 0.04 g (50%) of final title compound as a tan powder: mp 103-105°C; IR (KBr) v_max 3422, 3295, 2965, 1697, 1649, 1537, 1512, 1244 cm^-1; ¹H NMR (DMSO-d₆) δ 9.19 (bs, 1 H), 8.61-8.43 (m, 4 H), 7.75-7.59 (m, 2 H), 7.45-7.28 (m, 7 H), 7.09 (d, 2 H, J = 8.5 Hz), 6.81 (d, 2 H, J = 8.5 Hz), 5.09-4.98 (m, 4 H), 4.50-4.26 (m, 3 H), 3.90-3.61 (m, 2 H), 3.12 (m, 2 H), 2.55 (m, 1 H), 1.79 (m, 1 H), 1.27 (t, 5 H, J = 8.6 Hz), 0.77 (t, 1 H, J = 6.2 Hz); ¹⁹F NMR (DMSO-d₆) δ minor diastereomer: -111.34 (apparent doublet, J = 184 Hz), major diastereomer: -113.24 (d, J = 254 Hz), -117.56 (d, J = 254 Hz); mass spectrum, m/z 674 Z⁺ + 1), 565, 460, 252, 207, 143, 138, 110 (100), 92.

Anal. Calcd for C₃6H₃7F₂N₅O₆•2H₂O: C, 60.93; H, 5.78; N, 9.87. Found: C, 60.00; H, 6.15; N, 9.56.

Example 15

Preparation of [1-[[[3,3-Difluoro-2,4-dioxo-1-[[4- (phenylmethoxy)-phenyl ]-methyl]-4-[(2- pyridinylmethyl)amino]butyl]-amino]carbonyl]- 2- methylpropyl]-carbamic Acid, 2-Pyridinylmethyl Ester.

Step A

Preparation of N-[(2-Pyridinylmethoxy)carbonyl]-L-valine

Methyl Ester.

In a manner analogous to the preparation of N-[(3- pyridinylmethoxy)carbonyl]-L-valine in example 8, the title compound is prepared from L-valine methyl ester

hydrochloride (5.0 g, 30 mmol), triphosgene (4.66 g, 15.7 mmol), and (n-Bu)₃N (0.05 mL, 0.4 mmol); however, 2-pyridyl- carbinol (10.0 mL, 100 mmol, 3.3 equivalents) is added dropwise to the intermediate isocyanate. Flash

chromatography as in example 8 provides 2.63 g (33%) of title compound as a yellow oil: IR (neat) v_max 3345, 2965. 1726, 1533, 1439, 1314, 1271, 1236, 1213, 1105 cm^-1; ¹H NMR (CHCl₃) δ 8.61 (d, 1 H, J = 4.6 Hz), 7.7 (td, 1 H, J = 7.6, 1.8 Hz), 7.38 (d, 1 H, J = 7.7 Hz), 7.27 (dd, 1 H, J = 7.3, 4.6 Hz), 5.45 (d, 1 H, J = 8.9 Hz), 5.25 (s, 2 H), 4.35 (dd, 1 H, J = 9.2, 4.7 Hz), 3.75 (s, 3 H), 2.24 (m, 1 H), 1.0 (d, 3 H, J = 6.8 Hz), 0.9 d, 3 H, J = 6.8 Hz); ¹³C NMR (CDCI₃) δ 172.4, 156.2, 155.9, 149.4, 136.7, 122.7, 121.6, 67.4, 59.1, 52.1, 31.2, 18.9, 17.5; mass spectrum, m/z 267 (M⁺ + 1, 100), 136, 110.

Anal. Calcd for C₁₃H₁₈N₂O₄: C, 58.65; H, 6.77; N, 10.53. Found: C, 58.25; H, 6.86; N, 10.46.

Step B

Preparation of N-[(2-Pyridinylmethoxy)carbonyl]-L-valine.

Hydrolysis of the above ester (2.5 g, 9.4 mmol) with LiOH•H₂O (0.79 g, 18.8 mmol) in CH₃OH in a manner analogous to that described previously in example 8 provides 2.0 g

(85%) of the title compound as a white solid: IR (KBr) v_max 3366, 3065, 2963, 2936, 1722, 1616, 1602, 1577, 1526, 1433, 1279, 1250, 1219, 1109, 764, 627 cm^-1; ¹H NMR (DMSO-d₆) δ 8.58 (d, 1 H, J = 4.7 Hz), 7.96 (t, 1 H, J = 8.0 Hz), 7.6 (d, 1 H, J = 8.0 Hz), 7.43 (d, 1 H, J = 7.5 Hz), 7.4 (dd, 1 H, J = 7.5, 5.2 Hz), 5.15 (s, 2 H), 3.9 (dd, 1 H, J = 8.5, 5.9 Hz), 2.1 (m, 1 H), 0.92 (dd, 6 H, J = 6.6, 3.7 Hz); ¹³C NMR (DMSO-d₆) δ 173.1, 156.3, 156.2, 148.6, 137.4, 123.0, 121.4, 65.9, 59.6, 29.5, 19.1, 18.0; mass spectrum, m/z 253 (M⁺ + 1), 237, 209, 136 (100), 109, 92, 65.

Step C

Preparation of [3ξ, 4(S)]-2,4,5-Trideoxy-2,2-difluoro-4-

[[3-methyl-1-oxo-2-[[(2- pyridinylmethoxy)carbonyl]amino]butyl]amino]-5-[4-(phenylmethoxy)phenyl]-N-(2-pyridinylmethyl)-L-glycero- pentanamide.

Reaction Schemes A and A', steps (d) and (e): The

[1 (R), 3ξ]-2,4,5-trideoxy-4-[[(1,1- dimethylethoxy)carbonyl]-amino]-2,2-difluoro-5-[4-

(phenylmethoxy)-phenyl]-N-(2-pyridinylmethyl)-L-glycero- pentonamide (0.34 g, 0.63 mmol) prepared in example 13, step A, is deprotected as in example 13, step (d) and coupled with the above prepared acid (0.21 g, 0.82 mmol) under standard coupling conditions in a manner analogous to that described previously to provide 0.14g (30%) of title compound as a white powder: mp 224-225.5°C; IR (KBr) v_max 3291, 1697, 1680, 1657, 1618, 1599, 1572, 1537, 1512, 1454, 1439, 1398, 1341, 1300, 1244, 700 cm^-1; ¹H NMR (DMSO-d₆) δ 9.31 (bs, 1 H), 7.82-7.71 (m, 3H), 7.48-7.23 (m, 10 H), 7.10 (d, 2 H, J = 8.6 Hz), 6.82 (d, 2 H, J = 8.6 Hz), 5.05- 4.95 (m, 4 H), 4.47 (d, 2 H, J = 5.8 Hz), 4.23 (m, 1 H), 4.04 (m, 1 H), 3.79 (t, 1 H, J = 6.0 Hz), 4.40 and 3.69 and 3.14 (3m, 1 H total), 2.94 (d, 1 H, J = 13.0 Hz), 2.63 (dd, 1 H, J = 14.6, 10.8 Hz), 1.83 (m, 1 H), 0.70 (dd, 5 H, J = 9.2, 7.1 Hz), 0.57 and 0.47 (2d, 1 H total, J = 6.9 Hz); ¹³C NMR (DMSO-d₆) δ 170.1, 157.4, 156.7, 156.6, 155.7, 148.97, 148.8, 137.2, 136.8, 130.76, 130.21, 128.4, 127.7, 127.5, 122.75, 122.25, 121.0, 120.8, 114.2, 69.0, 66.2, 60.38, 49.9, 44.1, 44.0, 34.0, 30.3, 19.2, 17.95; ¹⁹F NMR (DMSO-d₆) δ major diastereomer: -110.07 (d, J = 248 Hz), - 119.9 ((d, J = 252 Hz), minor diastereomer: -110.03 (dm, J = 250 Hz), -118.34 (dm, J = 250 Hz), -111.72 (dm, J = 250 Hz), -123.5 (dm, J = 250 Hz); mass spectrum, m/z 676 (M⁺ + 1), 595, 567, 110, 92 (100). Step D

Preparation of final title compound.

Reaction Scheme A', step (f): The above alcohol (0.13 g, 0.19 mmol) is oxidized under Swern condition in a manner analogous to that described previously in example 1 to provide after flash chromatography (8:1 CH₂CI₂/C₂H₅OH) 0.04 g (30%) of a 1:1 mixture of the final title compound as a tan powder: mp 140-142°C; IR (KBr) v_max 3304, 1695, 1668, 1537, 1514, 1439, 1296, 1244, 1109, 1042 cm^-1; ¹H NMR (DMSO- d₆) δ 9.09 and 8.85 and 8.09 (d, m, d, 1 H total), 8.56 (m, 1 H), 8.17 (m, 1 H), 7.78-7.65 (m, 2 H), 7.45-7.15 (m, 10 H), 7.05 (d, 2 H, J = 8.6 Hz), 6.89 (d, 2 H, J = 8.6 Hz), 5.56 and 5.43 (2d, 1 H total, J = 9.2, 9.2 Hz), 5.30-4.95 (m, 5 H), 4.84-4.45 (m, 2 H), 3.85-3.7 (m, 1 H), 3.32-3.27 (2d,1 H, J = 4.9, 4.0 Hz), 3.16-2.80 (2m, 1 H), 1.90-1.70 (m, 1 H), 0.83-0.75 (m, 5 H), 0.56 (d, 1 H, J = 6.8 Hz); ¹⁹F NMR (DMSO-d₆) δ -110.07 (d, J = 275 Hz), -113.25 (apparent d, J = 9 Hz), -113.45 (d, J = 276 Hz), Hydrate: -118.5 (d, J = 257 Hz), -121.00 (d, J = 253 Hz); mass spectrum, m/z 674 (M⁺ 1), 460, 143, 110, 92.

Example 16

Preparation of [1-[[[3,3-Difluoro-2,4-dioxo-1-[[4- (phenylmethoxy)-phenyl]-methyl]-4-[(3- pyridinylmethyl)amino]butyl]-amino]carbonyl]- 2- methylpropyp-carbamic Acid, 2-Pyridinylmethyl Ester.

Step A

Preparation of [3ξ, 4(S)]-2,4,5-Trideoxy-2,2-difluoro-4- [[3-methyl-1-oxo-2-[[(2- pyridinylmethoxy ) carbonyl]amino]butyl]amino]-5-[4-(phenylmethoxy)phenyl]-N-(3-pyridinylmethyl)-L-glycero- pentanamide.

Reaction Schemes A and A', steps (d) and (e): The [1 (R), 3ζ]-2,4,5-trideoxy-4-[[(1,1-dimethylethoxy)carbonyl]- amino ] -2,2-difluoro-5-[4-(phenylmethoxy) -phenyl ] -N-(3- pyridinylmethyl)-L-glycero-pentonamide

(0.357 g, 0.709 mmol) prepared in example 14, step A, is deprotected as in example 14, step (d) and coupled with N- [(2-pyridinylmethoxy)carbonyl]-L-valine (0.157 g, 0.620 mmol) prepared in example 15, under standard coupling conditions described previously to provide after treating the crude material with hot CH₃OH, filtering, and

concentrating under vacuum, 180 mg (54%) of title compound as a white powder: IR (KBr) v_max 3298, 1697, 1680, 1659, 1537, 1512, 1298, 1244, 1103 cm^-1; ¹H NMR (DMSO-d₆) δ 9.3 9.32 (m, 1 H), 8.52-8.46 (m, 3 H), 7.82-7.68 (m, 3 H), 7.41-7.26 (m, 7 H), 7.19 (d, 1 H, J = 9.6 Hz), 7.07 (d, 2 H, J = 8.4 Hz), 6.81 (d, 2 H, J = 8.4 Hz), 6.27 (d, 1 H, J = 7.2 Hz), 5.12 (d, 1 H, J = 13.5 Hz), 5.06 (d, 1 H, J = 13.5 Hz), 5.02 (d, 1 H, J = 12.0 Hz), 4.97 (d, 1 H, J = 12.0 Hz), 4.44 (dd, 1 H, J = 15.3, 6.0 Hz), 4.35 (dd, 1 H, J = 15.3, 5.7 Hz), 4.24-4.15 (m, 1 H), 4.11 (dd, 1 H, J = 10.5, 5.1 Hz), 4.06-3.95 (m, 1 H), 3.79 (dd, 1 H, J = 9.3, 6.9 Hz), 2.93-2.88 (m, 1 H), 2.60 (dd, 1 H, J = 13.8, 11.1 Hz), 1.82-1.77 (m, 1 H), 0.71 (d, 3H, J = 6.9 Hz), 0.68 (d, 3H, J = 6.9 Hz); ¹⁹F NMR (DMSO-d₆) δ -109.87 (dd, J = 252, 8 Hz), -120.07 (dd, J = 253, 17 Hz); mass spectrum, m/z 704 (M⁺ + 29), 676 (M⁺ + 1), 424, 241, 138, 110, 92 (100).

Anal. Calcd for C₃₆H₃₉F₂N₅O₆: C, 63.99; H, 5.82; N, 10.36. Found: C, 60.62; H, 5.97; N, 9.83.

Step B

Preparation of final title compound.

Reaction Scheme A', step (f): In a manner analogous to that described previously in example 1, the above prepared alcohol (152 mg, 0.225 mmol) is oxidized under Swern conditions to provide after flash chromatography (19:1 CHCl₃/CH₃OH) 104 mg (68%) of final title compound which is recrystallized twice from CH₂Cl₂/pentane to provide 34 mg (22%) of final title compound as a cream powder: mp 97- 102°C; IR (KBr) v_max 3405, 3324, 1699, 1534, 1512, 1437, 1242, 1178, 1113 cm^-1; ¹H NMR (CDCI₃) δ 8.56-8.51 (m, 3H), 7.71-7.62 (m, 2 H), 7.43-7.19 (m, 10 H), 7.10-7.05 (m, 2 H), 6.91-6.83 (m, 2 H), 6.48-6.37 (m, 1 H), 5.48-5.10 (m, 3H), 5.02 and 5.00 (2s, 2 H total), 4.61-4.46 (m, 2 H),

3.90 and 3.87-3.81 (dd and m, 1 H total, J = 8.7, 6.1 Hz), 3.36-3.23 (m, 1 H), 2.91-2.73 (m, 1 H total), 2.07-1.88 (m, 1 H), 0.86 and 0.79 and 0.76 and 0.75 and 0.61 and 0.59 (6d, 6 H total, J = 6.6 Hz); ¹⁹F NMR (CDCI₃) δ -111.65 (d, J = 277 Hz), -111.73 (d, J = 276 Hz), -113.15 (d, J = 276

Hz), -113.20 (d, J = 277 Hz), Hydrate: -115.64 (d, J = 257 Hz), -116.55 (d, J = 256 Hz), -120.42 (d, J = 256 Hz), - 121.55 (d, J = 256 Hz); mass spectrum, m/z 702 (M⁺ + 29), 674 (M⁺ + 1), 138, 110, 92 (100). Anal. Calcd for

C₃₆H₃₇F₂N₅O₆: C, 64.18; H, 5.54; N, 11.87. Found: C, 61.96; H, 5.80; N, 10.38. Example 17

Preparation of N-[4-(N-{2-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-(3-pyridylmethyl)-D-valinol.

Step A

Preparation of N-trityl-D-valinol.

A solution of D-valinol (4.95 g, 48.06 mmol),

triethylamine (7.4 mL, 52.87 mmol) and trityl chloride (14.74 g, 52.87 mmol) in dry dichloromethane (75 mL) is stirred for 17 hours at room temperature. The organic solution is washed with water (2 x 75 mL), dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The resulting oil is purified by flash

chromatography (silica gel, ethyl acetate/petroleum ether, 15/85) to provide the title compound (13.5 g, 81%); R_f=0.45 (ethyl acetate petroleum ether, 15/85).

Step B

Preparation of N-trityl-O-3-pyridylmethyl-D-valinol.

Under a nitrogen atmosphere, to a suspension of sodium hydride (1.3 g, 30 mmol, 55% dispersion in oil, previously washed twice with pentane) in dry DMF (3 mL) is added with stirring, a solution of N-trityl-D-valinol (3.45 g, 10 mmol) in DMF (23 mL). The reaction is stirred for 30 minutes at room temperature and then cooled to 0°C and tetrabutylammonium iodide (0.37 g, 1 mmol) is added. Then 3-picolyl chloride HCl (1.81 g, 11 mmol) is added to the reaction in portions over 5 minutes. After addition is complete, the cooling bath is removed and the mixture allowed to stirr for 17 hours at room temperature. The reaction mixture is then cooled with an ice bath and hydrolyzed with water (100 mL). The mixture is then extracted with ethyl acetate (2 x 100 mL). The organic extracts are washed with water (2 x 50 mL), combined, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The resulting yellow oil is purified by flash chromatography (silica gel, dichloromethane/ethyl acetate, 9/1, R_f=0.42) to provide the title compound (3.4 g, 78%) as an oil.

Step C

Preparation of O-3-pyridylmethyl-D-valinol.

A solution of N-trityl-O-3-pyridylmethyl-D-valinol

(3.63 g, 8.3 mmol) in formic acid (30 mL) is kept for 5.5 hours at room temperature. The formic acid is removed under vacuum and the residue is dissolved in water (100 mL). The mixture is extracted with ethyl acetate (100 mL, 50 mL) to remove the trityl alcohol. The aqueous phase is then made basic with saturated sodium carbonate (50 mL) and 4N sodium hydroxide (3 mL). The aqueous mixture is then extracted with ethyl acetate (4 x 50 mL). The organic extracts are rinsed with brine (2 x 50 mL), combined, dried over sodium sulfate, filtered and concentrated under vacuum to provide the title compound (1.32 g, 82%) R_f=0.12 (silica gel, dichloromethane/methanol, 8/2).

Step D

Preparation of N-[4-tert-butoxycarbonylamino-2,2-difluoro-

3-hydroxy-1-oxo-5-(4-benzyloxy)phenyl-pentyl]-O-(3- pyridylmethyl)-D-valinol.

Reaction Scheme A, step (b); A solution of the ester

(1.14 g, 2.38 mmol, prepared in example 1, step B) and of O-3-pyridylmethyl-D-valinol (1.32 g, 6.8 mmol, prepared in step C above) in dry tetrahydrofuran (1.5 mL) is heated for

2 days under reflux. After cooling, the reaction mixture is diluted with ethyl acetate (5 mL), pentane (10 mL) and the precipitate is collected by filtration. The filtrate is rinsed with pentane and recrystallized from

dichloromethane/methanol/pentane to provide the title compound (0.8 g, 54%) as a white solid, R_f=0.5 (silica gel ethyl acetate); mass spectrum, m/z 628 (MH⁺).

Step E

Preparation of N-[4-amino-2,2-difluoro-3-hydroxy-1-oxo-5- (N-(benzyloxy)phenyl-pentyl]-O-(3-pyridylmethyl)-D-valinol.

Reaction Scheme A, step (d); The title compound is obtained in 91% yield following the deprotection procedure in an analogous manner described in Example 17, step C; mass spectrum, m/z 528 (MH⁺).

Step F

Preparation of N-[4-(N-{2-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-3-hvdroxy-1-oxo-5-(4- benzyloxy)phenyl-pentyl3-O-(3-pyridylmethyl)-D-valinol.

Reaction Scheme A', step (e); To a solution of N-(2- pyridylmethyloxycarbonyl)-L-valine (0.101 g, 0.4 mmol, prepared in Example 15, step B), in anhydrous DMF (2 mL) are added under an atmosphere of nitrogen, N- hydroxybenztriazole hydrate (0.115 g, 0.4 mmol), 1-ethyl- 3(3-dimethylaminopropyl)carbodiimide (0.085 g, 0.44 mmol) and DMF (1 mL). The reaction mixture is allowed to stir for 30 minutes at room temperature and N-[4-amino-2,2- difluoro-3-hydroxy-1-oxo-5-(N-(benzyloxy)phenyl-pentyl]-O- ( 3-pyridylmethyl)-D-valinol (0.211 g, 0.4 mmol, prepared above) in DMF (1 mL) is added. The reaction is allowed to stir for 15 hours, then diluted with ethyl acetate (80 mL) and washed with water ( 2 x 80 mL). The aqueous rinses are extracted with ethyl acetate (80 mL). The combined organic extracts are dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue is purified by flash chromatography (2x, silica gel, dichloromethane/ethanol, 95/5, R_f=0.15) to provide the title compound (0.170 g, 56%); mass spectrum, m/z 762 (MH⁺).

Step G

Preparation of final title compound.

Reaction Scheme A', step (f); To a solution of oxalyl chloride (0.195 mL, 2.23 mmol) in anhydrous dichloromethane (0.5 mL) at -60°C is added slowly under an atmosphere of nitrogen, freshly distilled dimethyl sulfoxide (0.316 mL, 4.46 mmol) in dichloromethane (1.5 mL). After 10 minutes of stirring at -60°C, the temperature is allowed to rise to -15°C. A mixture of a solution of the alcohol prepared above (0.170 g, 0.223 mmol) in dichloromethane (7 mL) and dimethylsulfoxide (0.5 mL) is added to the reaction

dropwise. The reaction is then stirred for 1.75 hours at - 15°C and then cooled to -78°C. Diisopropylethylamine (0.93 mL, 6.69 mmol) is added and the reaction is stirred an additional 10 minutes. The reaction is then allowed to warm to room temperature and is diluted with

dichloromethane (25 mL). The reaction mixture is washed with water (2 x 25 mL). The aqueous washes are extracted with dichloromethane (25 mL). The combined organic

extracts are dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue is purified by flash chromatography (silica gel, ethyl acetate, R_f=0.17) followed by recrystallization from dichloromethane/pentane to provide the title compound (0.120 g, 71%); mass

spectrum, m/z 760 (MH⁺); ¹H NMR (DMSO-d₆) δ 9.12-8.96 (m, 1H), 8.66-8.55 (m, 2H), 7.96-7.85 (m, 1H), 7.85-7.75 (m, 1H), 7.60-7.35 (m, 7H), 7.30-7.19 (m, 2H), 7.08-6.83 (m, 2H), 5.20 (s, 2H), 5.17-5.05 (m, 3H), 4.65-4.53 (m, 2H), 4.07-3.87 (2m, 2H), 3.72-3.60 (m, 2H), 3.28-3.14 and 2.86- 2.78 (m, 2H), 2.09-1.83 (m, 2H), 1.27-0.67 (m, 12H); ¹⁹F NMR (DMSO-d₆, T=60°C) δ (C₆F₆) 52.94 (d, J=269 Hz), 52.30 (d, J=270 Hz), 51.25 (d, J=270 Hz), 50.35 (d, J=269 Hz).

Anal. Calcd for C₄₁H₄₇N₅O7F₂, 0.25 H₂O: C, 64.43; H, 6.26; N, 9.16; Found C, 64.24; H, 6.25; N, 9.01.

Example 18

Preparation N-[4-(N-{3-pyridylmethyl}oxycarbonyl-L- valypamino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-(3-pyridylmethyl)-D-valinol.

Step A

Preparation of N-[4-(N-{3-pyridylmethyl)oxycarbonyl-L- valyl)amino-2,2-difluoro-3-hydroxy-1-oxo-5-(4- benzyloxy)phenyl-pentyl]-O-(3-pyridylmethyl)-D-valinol.

Reaction Scheme A', step (e); The title compound is prepared in a manner analogous to the coupling procedure described in Example 17, Step F, utilizing the amine prepared in Example 17, Step E, and the acid prepared in Example 8, Step A. The title compound is obtained in 84% yield, R_f=0.43 (silica gel, dichloromethane/ethanol, 95/5); mass spectrum, m/z 762 (MH⁺).

Anal. Calcd for C₄₁H₄₉N₅O₇F₂•0.5 H₂O: C, 63.88; H, 6.54; N, 9.08;

Found C, 63.87; H, 6.47; N, 9.06.

Step B

Preparation of Final Title Compound.

Reaction Scheme A', step (f); The title compound is prepared in a manner analogous to the Swern Oxidation described in Example 17, Reaction Scheme A', step (f), utilizing the above alcohol. The title compound is obtained in 50% yield, R_f=0.1 (silica gel, ethyl acetate) ¹H NMR (DMSO-d₆) δ 9.04-8.90 (m, 1H), 8.71-8.50 (m, 3H), 7.90-7.70 (m, 2H), 7.60-6.85 (m, 12H), 5.27-5.02 (m, 5H), 4.50-4.66 (m, 2H), 3.85-4.07 (m, 2H), 3.72-3.57 (m, 2H), 3.30-3.12 and 2.85-2.65 (m, 2H), 2.05-1.8 (m, 2H), 1.20- 0.59 (m, 12H); ¹⁹F NMR (DMSO-d₆) δ (C₆F₆) 52.93 (d, J=268 Hz), 52.15 (d, J=269 Hz), 50.92 (d, J=269 Hz), 49.68 (d, J=268 Hz); hydrates, 49.31 (d, J=254 Hz), 48.31 (d, J=254 Hz), 46.22 (d, J=254 Hz), 44.68 (d, J=254 Hz).

Anal. Calcd for C₄₁H₄₇N₅O₇F₂, H₂O: C, 63.31; H, 6.35; N, 9.00;

Found C, 62.56; H, 6.26; N, 8.66.

Example 19

Preparation of N-[4-(N-{3-pyridylmethyl}oxycarbonyl-L- valypamino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-methyl -D-valinol.

Step A

Preparation of N-tert-butoxycarbonyl-D-valinol.

A solution of D-valinol (5.1 g, 49.4 mmol) and di-tert- butyldicarbonate (10.9 g, 50 mmol), in methanol (60 mL) is stirred for 17 hours at room temperature. The reaction is concentrated under vacuum and the residue is purified by flash chromatography (silica gel, ethyl acetate/petroleum ether, 3/7, R_f=0.37) to provide the title compound in quantitative yield (10.07 g) as a colorless oil; mass spectrum, m/z 204 (MH⁺). Step B

Preparation of N-tert-Butoxycarbonyl-O-methyl-D-valinol.

To a solution of N-tert-butoxycarbonyl-D-valinol (5.075 g, 25 mmol) and methyl iodide (27.5 mL of a 1M solution in tetrahydrofuran, 27.5 mmol) in dry tetrahydrofuran (45 mL) under an atmosphere of nitrogen at 0°C, is added with stirring, potassium-tert-butoxide (3.086 g, 27.5 mmol) in 3 portions. The reaction mixture is kept at room temperature for 5.5 hours, then hydrolyzed with a saturated solution of sodium chloride and extracted with ethyl acetate (2 x 300 mL). The organic extracts are washed with brine (2 x 300 mL), combined, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue is purified by flash chromatography (silica gel, ethyl

acetate/petroleum ether, 1/9, R_f=0.25) to provide the title compound (2.93 g, 54%) as an oil.

Step C

Preparation of O-methyl-D-valinol.

A solution of N-tert-butoxycarbonyl-O-methyl-D-valinol (2.93 g, 13.5 mmol) in dry ether saturated with hydrogen chloride (11 mL) is stirred at room temperature for 3.5 hours. The reaction is then concentrated under vacuum. Pentane (50 mL) is added to the residue, followed by addition of diethylamine (7 mL). The mixture is then stirred for 10 minutes and the solid is removed by

filtration. The filtrate is concentrated under vacuum(150 bars) at room temperature to provide the title compound (1.30 g, 82%) as a colorless oil.

Step D

Preparation of N-[4-tert-butoxycarbonylamino-2,2-difluoro- 3-hydroxy-1-oxo-5-(4-benzyloxy)phenyl-pentyl]-O-methyl-D- valinol.

Reaction Scheme A, step (b); The title compound is prepared in a manner analogous to the procedure of Example 17, Step D, from the ester of Example 1, step B and the above prepared O-methyl-D-valinol followed by flash

chromatography (78% yield); R_f=0.19 (minor) and 0.09

(major) (silica gel, ethyl acetate/petroleum ether, 35/65); mass spectrum, m/z 551 (MH⁺), 568 (MNH₄ ⁺).

Step E

Preparation of N-[4-amino-2,2-difluoro-3-hydroxy-1-oxo-5-

(4-benzyloxy)phenyl-pentyl]-O-methyl-D-valinol.

Reaction Scheme A, step (d); The title compound is prepared in a manner analogous to the deprotection

procedure of Example 17, step C, from N-[4-tert- butoxycarbonylamino-2,2-difluoro-3-hydroxy-1-oxo-5-(4- butyloxy)phenyl-pentyl]-O-methyl-D-valinol

prepared above (quantitative yield); mass spectrum, m/z 451 (MH⁺).

Step F

Preparation of N-[4-(N-{3-pyridylmethyl)oxycarbonyl-L- valyl)amino-2,2-difluoro-3-hydroxy-1-oxo-5-(4- benzyloxy)phenyl-pentyl]-O-methyl-D-valinol.

Reaction Scheme A', step (e); The title compound is prepared in a manner analogous to the coupling method described in Example 17, step F, from N-[4-amino-2,2- difluoro-3-hydroxy-1-oxo-5-(4-benzyloxy)phenyl-pentyl]-O- methyl-D-valinol prepared above and the acid prepared in Example 8, Step A. Purification by crystallization (ethyl acetate plus 10% ethanol/pentane) provides the title compound in 58% yield; mass spectrum, m/z 685 (MH⁺). Step G

Preparation of final title compound.

Reaction Scheme A', step (f); The final title compound is prepared in a manner analogous to the Swern Oxidation described in Example 17, step G from N-[4-(N-{3- pyridylmethyl}oxycarbonyl-L-valyl)amino-2,2-difluoro-3- hydroxy-1-oxo-5-(4-benzyloxy)phenyl-pentyl]-O-methyl-D- valinol prepared above (15% yield, R_f=0.1, silica gel. dichloromethane/ethyl acetate, 4/6); ¹H NMR (DMSO-d₆) δ 9.07-8.93 (m, 1H), 8.87-8.50 (m, 2H), 8.40-8.31 (m, 1H), 7.94-7.81 (m, 1H), 7.60-6.59 (several m, 11H), 5.29-5.01 (m, 5H), 4.10-3.78 (m, 2H), 3.58-3.43 (m, 2H), 3.35-3.25 (several s, 3H), 3.30-3.08 and 2.85-2.63 (m, 2H), 2.11- 1.72 (m, 2H), 1.04-0.48 (m, 12H); ¹⁹F NMR (DMSO-d₆) δ (C₆F₆) 53.27 (d, J=267 Hz), 52.60 (d, J=269 Hz), 51.32 (d, J=269 Hz), 49.76 (d, J=267 Hz), 49.89 (d, J=254 Hz), 48.61 (d, J=254 Hz), 46.49 (d, J=254 Hz), 44.73 (J=254 Hz); mass spectrum, m/z 683 (MH⁺) .

Anal. Calcd for C₃₆H₄₄N₄O7F₂, H₂O: C, 61.70; H, 6.62; N, 7.99;

Found C, 62.07; H, 6.46; N, 7.84. Example 20

Preparation of N-{4-(N-{3-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-(2-pyridylmethyl)-D-valinol.

Step A

Preparation of N-trityl-O-2-pyridylmethyl-D-valinol.

The title compound is prepared in a manner analogous to the procedure described in Example 17, step B from the alcohol of Example 17, step A and 2-picolyl chloride HCl, in 81% yield, R_f=0.52 (silica gel, dichloromethane/ethyl acetate, 9/1).

Step B

Preparation of O-2-pyridylmethyl-D-valinol.

The title compound is prepared in a manner analogous to the procedure described in Example 17, step C from N- trityl-O-2-pyridylmethyl-D-valinol prepared above, in 80% yield.

Step C

Preparation of N-[4-tert-butoxycarbonylamino-2,2-difluoro- 3-hydroxy-1-oxo-5-(4-benzyloxy)phenyl-pentyl]-O-(2- pyridylmethyl)-D-valinol.

Reaction Scheme A, step (b); The title compound is prepared in a manner analogous to the procedure described in Example 17, Step D, from the ester of Example 1, step B and O-2-pyridylmethyl-D-valinol, prepared above, in 63% yield, R_f=0.65 (silica gel, ethyl acetate).

Step D

Preparation of N-[4-amino-2,2-difluoro-3-hydroxy-1-oxo-5- (4-benzyloxy)phenyl-pentyl]-O-(2-pyridylmethyl)-D-valinol.

Reaction Scheme A, step (d); The title compound is prepared in a manner analogous to the deprotection

procedure described in Example 17, step C from N-[4-tert- butoxycarbonylamino-2,2-difluoro-3-hydroxy-1-oxo-5(4- benzyloxy) phenyl-pentyl]-O-(2-pyridylmethyl)-D-valinol, prepared above, in 91% yield which is used directly in the next step; mass spectrum, m/z 628 (MH⁺). Step E

Preparation of N-[4-(N-{3-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-3-hydroxy-1-oxo-5-(4- benzyloxy)phenyl-pentyl]-O-(2-pyridylmethyl)-D-valinol.

Reaction Scheme A', step (e); The title compound is prepared in a manner analogous to the procedure described in Example 17, step F from the amine prepared above and the acid prepared in Example 8, Step A, in 53% yield, R_f=0.14 (major) and 0.08 (minor) (silica gel,

dichloromethane/ethanol, 95/5); mass spectrum, m/z 762 (MH⁺). Step F

Preparation of final title compound.

Reaction Scheme A', step (f); The final title compound is prepared in a manner analogous to the Swern Oxidation procedure described in Example 17, step G from the above prepared alcohol, in 72% yield, R_f=0.09 (silica gel, ethyl acetate); ¹H NMR (CHCl₃) δ 8.65-8.53 (m, 1H), 7.79-7.64 (m, 2H), 7.53-6.80 (several m, 14H), 6.60-6.10 (several m, 2H), 5.57-5.33 (m, 1H), 5.30-5.10 (m, 3H), 4.99 (s, 2H), 4.68- 4.56 (m, 2H), 4.03-3.85 (m, 2H), 3.85-3.34 (m, 2H), 3.42- 3.24 and 2.97-2.75 (m, 2H), 2.13-1.88 (m, 2H), 1.05-0.57 (m, 12H); ¹⁹F NMR (CDCI₃) δ (C₆F₆) 50.26 (d, J=271 Hz), 49.97 (d, J=263 Hz), 49.18 (d, J=261 Hz), 48.60 (d, J=271 Hz), 45.17 (d, J=252 Hz), 45.10 (d, J=251 Hz), 41.77 (d, J=252 Hz), 40.91 (d, J=251 Hz); mass spectrum, m/z 760 (MH⁺).

Anal. Calcd for C₄₁H₄₇N₅O₇F₂: C, 64.81; H, 6.23; N, 9.22; Found C, 62.91; H, 6.16; N, 8.66.

Example 21

Preparation of N-[ 4-(N-{2-pyridylmethyl)oxycarbonyl-L- valvl)amino-2,2-difluoro-1,3-dioxo-5-(4-{3- pyridylmethyl}oxy)phenyl-pentyl]-O-(3-pyridylmethyl)-D- valinol.

Step A

Preparation of 4-tert-butoxycarbonylamino-2,2-difluoro-3- hydroxy-5-(4-hydroxy)phenyl pentanoic acid, ethyl ester.

Reaction Scheme A, step (c₁); A solution of 4-tert- butoxycarbonylamino-2,2-difluoro-3-hydroxy-5-[(4- benzyloxy)phenyl]pentanoic acid, ethyl ester (0.719 g, 1.5 mmol) in ethanol (50 mL) is kept for 7.5 hours under an atmosphere of hydrogen in the presence of 10% palladium on charcoal (0.074 g). The hydrogen atmosphere is then exchanged with a nitrogen atmosphere, the suspension is filtered and the filtrate is concentrated under vacuum to provide the title compound (0.500g, 83%), R_f=0.51 (silica gel, petroleum ether/ethyl acetate, 1/1).

Step B

Preparation of N-[4-tert-butoxycarbonylamino-2,2-difluoro-

3-hydroxy-1-oxo-5-(4-hydroxy)phenyl-pentyl]-O-(3- pyridylmethyl)-D-valinol.

Reaction Scheme A, step (b); The title compound is prepared in a manner analogous to the procedure described in Example 19, step D, from the above prepared ester and the amine prepared in Example 17, step C, in 82% yield, R_f=0.46 (silica gel, ethyl acetate). Step C

Preparation of N-[4-tert-butoxycarbonylamino-2,2-difluoro- 3-hydroxy-1-oxo-5-(4-hydroxy)phenyl-pentyl]-O-(3- pyridylmethyl)-D-valinol.

Reaction Scheme A, step (C₂); A mixture of N-[4-tert- butoxycarbonylamino-2,2-difluoro-3-hydroxy-1-oxo-5-(4- hydroxy)phenyl-pentyl]-O-(3-pyridylmethyl)-D-valinol ( 0.37 g, 0.7 mmol, prepared above), 3-picolyl chloride HCl (0.16 g, 0.98 mmol), cesium carbonate (0.775 g, 2.38 mmol) and potassium iodide (0.016 g, 0.098 mmol) in anhydrous DMF (7 mL) is stirred for 66 hours under an atmosphere of

nitrogen. The reaction mixture is diluted with ethyl acetate (50 mL) and washed with water (2 x 50 mL). The aqueous rinses are extracted with ethyl acetate (50 mL). The combined organic extracts are dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue is purified by flash chromatography (silica gel, ethyl acetate/methanol, 95/5, R_f=0.25) to provide the title compound (0.245 g, 56%); mass spectrum m/z 629 (MH⁺). Step D

Preparation of N-[4-amino-2,2-difluoro-3-hydroxy-1-oxo-5- (4-{3-pyridylmethyl}oxy)phenyl-pentyl]-O-(3-pyridylmethyl) D-valinol.

Reaction Scheme A, step (d); The title compound is prepared in a manner analogous to the deprotection

procedure described in Example 17, step C from N-[4-tert- butoxycarbonylamino-2,2-difluoro-3-hydroxy-1-oxo-5-(4- hydroxy)phenyl-pentyl]-O-(3-pyridylmethyl)-D-valinol prepared above, in 84% yield; mass spectrum m/z 529 (MH⁺). Step E

Preparation of N-[4-{2-pyridylmethyl)oxycarbonyl-L- valyPamino-2,2-difluoro-3-hydroxy-1-oxo-5-(4-{3- pyridylmethyl}oxy)phenyl-pentyl)-O-(3-pyridylmethyl)-D- valinol.

Reaction Scheme A', step (e); The title compound is prepared in a manner analogous to the coupling procedure described in Example 17, step F, from the above prepared amine and the acid prepared in Example 15, step B, in 56% yield, R_f=0.20 (silica gel, dichloromethane/ethanol, 95/5); mass spectrum m/z 763 (MH⁺).

Step F

Preparation of final title compound.

Reaction Scheme A', step (f); The final title compound is prepared in a manner analogous to the Swern Oxidation procedure described in Example 17, step G from the above prepared alcohol, in 70% yield, R_f=0.19 (silica gel, ethyl acetate/acetone, 1/1); mass spectrum m/z 761 (MH⁺); ¹H NMR (DMSO-d₆) δ 9.11-8.97 (m, 1H), 8.80-8.50 (m, 5H), 8.50-8.30 (m, 1H), 8.13-7.70 (m, 4H), 7.69-6.60 (m, 8H), 5.40-5.00 (m, 5H), 4.71-4.49 (m, 2H), 4.10-3.80 (m, 2H), 3.80-3.51 (m, 2H), 3.51-3.30 and 2.86-2.60 (m, 2H), 2.12-1.72 (m, 2H), 1.17-0.47 (m, 12H); ¹⁹F NMR (DMSO-d₆) δ (C₆F₆) 52.91 (d, J=268 Hz), 52.11 (d, J=269 Hz), 50.86 (d, J=269 Hz), 50.42 (d, J=268 Hz), 49.34 (d, J=254 Hz), 48.39 (d, J=254 Hz), 46.17 (d, J=254 Hz), 44.63 (d, J=254 Hz).

Anal. Calcd for C₄₀H₄₆N₆O₇F₂: C, 63.15; H, 6.09; N, 11.05; Found C, 62.26; H, 6.24; N, 10.76.

Example 22

Preparation of N-[4-(N-{2-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-(2-pyridylmethyl)-D-valinol.

Step A

Preparation of N-[4-{2-pyridylmethyl)oxycarbonyl-L- valyl)amino-2,2-difluoro-3-hvdroxy-1-oxo-5-(4- benzyloxy)phenyl-pentyl]-O-(2-pyridylmethyl)-D-valinol.

Reaction Scheme A', step (e); The title compound is prepared in a manner analogous to the coupling procedure described in Example 17, step F from the amine prepared in Example 20, Reaction Scheme A, step (d) and the acid prepared in Example 15, step B, in 57% yield, R_f=0.17

(major) and 0.12 (minor) (silica gel,

dichloromethane/ethanol, 95/5); mass spectrum m/z 762 (MH⁺)

Step B

Preparation of final title compound.

Reaction Scheme A', step (f); The final title compound is prepared in a manner analogous to the Swern Oxidation procedure described in Example 17, step G from the above prepared alcohol, in 80% yield, R_f=0.22 (silica gel, ethyl acetate); mass spectrum m/z 760 (MH⁺); ¹H NMR (CDCI₃) δ 8.63-8.48 (m, 2H), 7.77-7.60 (m, 2H), 7.55-6.80 (several m, 13H), 6.49-6.02 (several m, 2H), 5.55-5.30 (m, 1H), 5.30- 4.95 (several m, 5H), 4.72-4.52 (m, 2H), 4.05-3.82 (m, 2H), 3.82-3.35 (m, 2H), 3.42-3.23 and 2.97-2.77 (m, 2H), 2.13- 1.83 (m, 2H), 1.05-0.54 (m, 12H); ¹⁹F NMR (CDCI₃) δ (C₆F₆) 50.18 (d, J=271 Hz), 49.87 (d, J=277 Hz), 49.02 (d, J=271 Hz), 48.41 (d, J=271 Hz), 44.97 (d, J=252 Hz), 44.78 (d, J=252 Hz), 41 . 85 ( d , J=252 Hz ) , 41. 12 ( d , J=252 Hz ) .

Anal . Calcd for C₄₁H₄₇N₅O₇F₂, H₂O; C, 63.31; H, 6.35; N, 9.00;

Found C, 63.37; H, 6.19; N, 8.85.

Example 23

Preparation of N-[4-(N-{2-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-methyl-D-valinol.

Step A

Preparation of N-[4-{2-pyridylmethyl)oxycarbonyl-L- valyl)amino-2,2-difluoro-3-hydroxy-1-oxo-5-(4- benzyloxy)phenyl-pentyl]-O-methyl-D-valinol.

Reaction Scheme A', step (e); The title compound is prepared in a manner analogous to the coupling procedure described in Example 17, step F from the amine prepared in Example 19, Reaction Scheme A, step (d) and the acid prepared in Example 15, step B, in 55% yield, R_f=0.23 (silica gel, ethyl acetate); mass spectrum m/z 685 (MH⁺). Anal. Calcd for C₃₆H₄₆N₄O₇F₂, 0.5 H₂O; C, 62.32; H, 6.83; N, 8.08;

Found C, 62.36; H, 6.64; N, 7.91.

Step B

Preparation of the final title compound.

Reaction Scheme A', step (f);The final title compound is prepared in a manner analogous to the Swern Oxidation procedure described in Example 17, step G from the above prepared alcohol, in 44% yield, R_f=0.3 (silica gel, dichloromethane/ethyl acetate, 3/7); mass spectrum m/z 683 (MH⁺); ¹H NMR (DMSO-d₆) δ 9.10-8.92 (m, 1H), 8.67-8.51 (m, 2H), 7.95-7.87 (m, 1H), 7.64-6.82 (several m, 11H), 5.30- 5.03 (m, 5H), 4.10-3.93 (m, 1H), 3.93-3.78(m, 1H), 3.60- 3.37 (m,2H), 3.35-3.25 (several s, 3H), 3.32-3.10 and 2.87- 2.68 (m, 2H), 2.14-1.80 (m, 2H), 1.10-0.60 (m, 12H); ¹⁹F NMR (DMSO-d₆) δ (C₆F₆) 52.80 (d, J=267 Hz), 52.21 (d, J=269 Hz), 50.93 (d, J=269 Hz), 52.21 (d, J=269 Hz), 50.93 (d, J=269 Hz), 49.36 (d, J=267 Hz).

Anal. Calcd for C₃₆H₄₄N₄O₇F₂, 0.5 H₂O; C, 62.51; H, 6.56; N,

8.10;

Found C, 62.65; H, 6.50; N, 7.93. Example 24

Preparation of N-{4-(N-{2-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-benzyl-D-valinol.

Step A

Preparation of N-[4-(N-{2-pyridylmethyl)oxycarbonyl-L- valyl)amino-2,2-difluoro-3-hydroxy-1-oxo-5-(4- benzyloxy)phenyl-pentyl]-O-benzyl-D-valinol.

Reaction Scheme A', step (e); The title compound is prepared in a manner analogous to the coupling procedure described in Example 17, step F from the amine prepared in Example 5, step B and the acid prepared in Example 15, step B in 52% yield, R_f=0.28 (silica gel, petroleum ether/ethyl acetate, 3/7).

Step B

Preparation of the final title compound. Reaction Scheme A', step (f); The final title compound is prepared in a manner analogous to the Swern Oxidation procedure described in Example 17, step G from the above prepared alcohol, in 62% yield, R_f=0.07 (Alumina neutral Act III, tetrahydrofuran/dichloromethane/water, 20/10/0.2), R_f=0.27 (silica gel, ethyl acetate/petroleum ether, 7/3); mass spectrum m/z 759 (MH⁺); ¹H NMR (CHCl₃) δ 8.73-8.51 (m,1H), 7.79-7.65 (m, 1H), 7.42-6.45 (several m, 18H), 5.70-5.10 (m, 4H), 5.06-4.93 (m, 2H), 4.58-4.40 (m, 2H), 4.05-3.80 (m, 2H), 3.74-3.58 and 3.55-3.40 (m, 2H), 3.35- 3.20 and 3.00-2.80 (m, 2H), 2.13-1.90 (m, 2H), 1.10-0.50 (m, 12H); ¹⁹F NMR (CDCI₃) δ (C₆F₆) 50.67 (d, J=273 Hz), 49.50 (broad s), 48.35 (d, J=273 Hz), 47.24 (d, J=255 Hz), 45.70 (d, J=255 Hz), 42.01 (d, J=255 Hz) 40.00 (d, J=255 Hz).

Anal. Calcd for C₄₂H₄₈N₄O₇F₂, 0.5 H₂O: C, 65.70; H, 6.43; N, 7.30;

Found C, 65.69; H, 6.25; N, 7.19.

Example 25

Preparation of N-{4-(N-{3-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-[2-(2-methoxyethoxy)-1-ethyl]-D-valinol.

Step A

Preparation of N-trityl-O-[2-(2-methoxyethoxy)-1-ethyl]-D- valinol.

The title compound is prepared in a manner analogous to the alkylation procedure described in Example 17, step B from the compound prepared in Example 17, step A and 2-(2- methoxyethoxy)ethyl-1-bromide in 86% yield, R_f=0.74 (silica gel, acetone/petroleum ether, 2/8). Step B

Preparation of O-[2-(2-methoxyethoxy)-1-ethyl]-D-valinol.

A solution of N-trityl-O-[2-(2-methoxyethoxy)-1-ethyl]- D-valinol (1.0 g, 2.28 mmol, prepared above) in dry ether saturated with hydrogen chloride (20 mL) is kept for 2.5 hours at room temperature. The reaction is concentrated under vacuum and the residue is purified by flash

chromatography (silica gel, dichloromethane first to elute the trityl alcohol and then dichloromethane/diethylamine, 95/5, R_f=0.20) to provide the title compound (0.46 g, 100%) as a colorless oil.

Step C

Preparation of N-[4-tert-butoxycarbonylamino-2,2-difluoro-

3-hydroxy-1-oxo-5-(4-benzyloxy)phenyl-pentyl]-O-[2-(2- methoxyethoxy)-1-ethyl]-D-valinol.

Reaction Scheme A, step (b); The title compound is prepared in a manner analogous to the procedure described in Example 19, step D from the ester of Example 1, step B and O-[2-(2-methoxyethoxy)-1-ethyl]-D-valinol, prepared above, in 51% yield, R_f=0.37 (silica gel, petroleum ether/ethyl acetate, 3/7).

Step D

Preparation of N-[4-amino-2,2-difluoro-3-hydroxy-1-oxo-5- (4-benzyloxy)phenyl-pentyl]-O-[2-(2-methoxyethoxy)-1- ethyl]-D-valinol.

Reaction Scheme A, step (d); The title compound is prepared in a manner analogous to the deprotection

procedure described in Example 17, step C from N-[4-tert- butoxycarbonylamino-2,2-difluoro-3-hydroxy-1-oxo-5-(4- benzyloxy)phenyl-pentyl]-O-[2-(2-methoxyethoxy)-1-ethyl]-D- valinol, prepared above, in 97% yield which is used directly in the next step; mass spectrum m/z 539 (MH⁺). Step E

Preparation of N-[4-(N-(3-pyridylmethyl)oxycarbonyl-L- valyl)amino-2,2-difluoro-3-hydroxy-1-oxo-5-(4- benzyloxy)phenyl-pentyl]-O-[2-(2-methoxyethoxy)-1-ethyl]-D- valinol.

Reaction Scheme A', step (e); The title compound is prepared in a manner analogous to the coupling procedure described in Example 17, step F from the amine prepared above and the acid prepared in Example 8, step A, in 52% yield, R_f=0.18 (silica gel, ethyl acetate); mass spectrum m/z 773 (MH⁺). Step F

Preparation of final title compound.

Reaction Scheme A', step (f); The final title compound is prepared in a manner analogous to the Swern Oxidation procedure described in Example 17, step G from the above prepared alcohol, in 76% yield, R_f=0.09 (silica gel, ethyl acetate); mass spectrum m/z 771 (MH⁺); ¹H NMR (DMSO-d₆) δ 9.05-8.88 (m, 1H), 8.77-8.55 (m, 2H), 8.40-8.27 (m, 1H), 7.94-7.81 (m, 1H), 7.76-6.55 (several m, 11H), 5.31-4.97 (m, 5H), 4.10-3.79 (m, 2H), 3.76-3.37 (m, 10H), 3.32 (s, 3H), 3.29-3.11 and 2.89-2.60 (m, 2H), 2.09-1.79 (m, 2H), 1.11-0.44 (m, 12H); ¹⁹F NMR (DMSO-d₆) δ (C₆F₆) 52.97 (d, J=267 Hz), 52.12 (d, J=269 Hz), 50.88 (d, J=269 Hz), 49.45 (d, J=254 Hz), 45.35 (d, J=267 Hz), 48.17 (d, J=254 Hz), 46.17 (d, J=254 Hz), 44.31 (d, J=254 Hz).

Anal. Calcd for C₄₀H₅₂N₄O₉F₂: C, 62.32; H, 6.80; N, 7.27; Found C, 61.78; H, 6.77; N, 7.12. Example 26

Preparation of N-[4-(N-{3-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-{2-N- morpholyl]ethyloxy)phenyl-pentyl]-O-methyl-D-valinol.

Step A

Preparation of N-[4-tert-butoxycarbonylamino-2,2-difluoro- 3-hydroxy-1-oxo-5-(4-hydroxy)phenyl-pentyl]-O-methyl-D- valinol.

Reaction Scheme A, step (b); The title compound is prepared in a manner analogous to the procedure described in Example 17, Step D, from the ester of Example 21, step A and the amine prepared in Example 19, step C, in 83% yield, R_f=0.15 (silica gel, petroleum ether/ethyl acetate, 6/4); mass spectrum m/z 461 (MH⁺).

Step B

Preparation of N-[4-tert-butoxycarbonylamino-2,2-difluoro- 3-hydroxy-1-oxo-5-(4-{2-N-morpholyl}ethyloxy)phenyl- pentyl]-O-methyl-D-valinol.

Reaction Scheme A, step (C₂); A mixture of N-[4-tert- butoxycarbonylamino-2,2-difluoro-3-hydroxy-1-oxo-5-(4- hydroxy)phenyl-pentyl]-O-methyl-D-valinol (1.117 g, 2.43 mmol, prepared above), N-(2-chloroethyl)morpholine HCl (0.633 g, 3.40 mmol), cesium carbonate (2.69 g, 8.26 mmol) and potassium iodide (0.056 g, 0.34 mmol) in dry DMF (20 mL) is stirred for 140 hours at room temperature. The reaction mixture is then diluted with ethyl acetate (100 mL) and washed with brine (2 x 100 mL). The aqueous washes are extracted with ethyl acetate (100 mL). The combined organic extracts are dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue is purified by flash chromatography (silica gel, ethyl

acetate, R_f=0.18) to provide the title compound (0.993 g, 71%).

Step C

Preparation of N-[4-amino-2,2-difluoro-3-hydroxy-1-oxo-5-

(4-(2-N-morpholyl}ethyloxy)phenyl-pentyl]-O-methyl-D- valinol.

Reaction Scheme A, step (d); The title compound is prepared in a manner analogous to the deprotection

procedure described in Example 17, step C from N-[4-tert- butoxycarbonylamino-2,2-difluoro-3-hydroxy-1-oxo-5-(4-{2-N- morpholyl}ethyloxy)phenyl-pentyl 3 -O-methyl-D-valinol, prepared above, in 85% yield which is used directly in the next step.

Step D

Preparation of N-[4-(N-{3-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-3-hydroxy-1-oxo-5-(4-{2-N- morpholyl}ethyloxy)phenyl-pentyl]-O-methyl-D-valinol.

Reaction Scheme A', step (e); The title compound is prepared in a manner analogous to the procedure described in Example 17, Step F from the amine prepared above and the acid prepared in Example 8, step A, in 80% yield, R_f=0.19

(silica gel, ethyl acetate/methanol, 9/1); mass spectrum m/z 708 (MH⁺). Step E

Preparation of final title compound.

Reaction Scheme A', step (f); A mixture of the above prepared alcohol (0.280 g, 0.396 mmol), 1,1,1-triacetoxy- 1,1-dihydro-1,2-benziodoxol-3(1H)-one (0.672 g, 1.583 mmol, Dess-Martin periodinane) and tert-butanol (0.075 mL, 0.792 mmol) in freshly distilled dichloromethane (10 mL,

distilled over P₂O₅) is stirred for 15 minutes at room temperature. The reaction mixture is then hydrolyzed with isopropanol (1.2 mL) and concentrated under vacuum. The residue is suspended in dichloromethane (3 mL), filtered through a Fluropore filter which is rinsed with

dichloromethane (2 x 1 mL). The filtrate is concentrated under vacuum and the residue purified by flash

chromotagraphy (2x, silica gel, dichloromethane/methanol, 99/1 to remove the by-products of the Dess-Martin Reagent, then 98/2 and 96/4 to elute the title compound) to provide the title compound (0.112 g, 28%), R_f=0.11

(dichloromethane/methanol, 95/5); mass spectrum m/z 706 (MH⁺); ¹H NMR (DMSO-d₆) δ 8.99-8.70 (m, 1H), 8.64-8.43 (m, 3H), 7.82-7.73 (m, 1H), 7.47-6.70 (several m, 6H), 5.16- 4.92 (m, 3H), 4.08-3.95 (broad s, 2H), 3.95-3.71 (m, 1H), 3.71-3.65 (m, 1H), 3.60-3.48 (broad s, 4H), 3.43-3.34 (m, 2H), 3.22-3.18 (2s, 3H), 3.24-3.03 and 2.77-2.56 (m, 2H), 2.54-2.34 (m, 4H), 2.02-1.70 (m, 2H), 1.10-0.50 (m, 12H); ¹⁹F NMR (DMSO-de) δ (C₆F₆) 52.87 (d, J=267 Hz), 52.22 (d, J=269 Hz), 50.91 (d, J=269 Hz), 49.38 (d, J=267 Hz).

Anal. Calcd for C₃₅H₄₉N₅O₈F₂•0.5 H₂O; C, 58.81; H, 7.05; N, 9.80;

Found C, 58.61; H, 6.88; N, 9.93.

In a further embodiment the present invention provides a method of treating a patient afflicted with a viral infection comprising the administration thereto of an effective antiviral amount of a compound of formula (I).

The term "viral infection" as used herein refers to an abnormal state or condition characterized by viral

transformation of cells, viral replication and

proliferation. Viral infections for which treatment with a compound of formula (I) will be particularly useful include retroviruses such as but not limited to HTLV-I, HTLV-II, HTLV-III (HIV virus), murine leukemia virus, feline

leukemia virus, cytomegalovirus(CMV), avian sarcoma virus and the like. In addition treatment with a compound of formula (I) would be useful in treating a wide range of states of HIV infection: AIDS, ARC (AIDS related complex), both symptomatic and asymptomatic, and actual or potential exposure to HIV. For example, the compounds of this

invention are useful in preventing infection by HIV after suspected past exposure to HIV by, e.g., blood transfusion, accidental needle stick, or exposure to patient blood during surgery.

An "effective antiviral amount" of a compound of formula (I) refers to an amount which is effective, upon single or multiple dose administration to the patient, in controlling the growth of the virus or in prolonging the survivability of the patient beyond that expected in the absence of such treatment. As used herein "controlling a viral infection" refers to slowing, interrupting, arresting or stopping the viral transformation of cells or the replication and proliferation of the virus and does not necessarily indicate a total elimination of the virus. The present invention further provides a method of inhibiting HIV protease in a patient in need thereof comprising administering to said patient an effective inhibitory amount of a compound of formula (I).

It is understood that patients suffering from a retrovirus, such as HTLV-III are in need of an HIV protease inhibitor such as a compound of formula (I).

As used herein, the term "patient" refers to a warmblooded animal, such as a mammal, which is afflicted with a particular viral infection. It is understood that humans, mice and rats are included within the scope of the term "patient".

Administration of a compound of formula (I) to a patient results in inhibition of HIV protease in the patient. Thus, by treatment of a patient with a compound of formula (I) retroviruses, such as HTLV-III, are

inhibited or suppressed. A patient is in need of treatment with an agent which inhibits HIV protease, such as a compound of formula (I), where the patient is suffering from certain viral

infections for which HIV protease is implicated as a contributing factor in the progression of the disease.

Based on standard clinical and laboratory tests and procedures, an attending diagnostician, as a person skilled in the art, can readily identify those patients who are in need of treatment with an agent which inhibits HIV

protease, such as a compound of formula (I).

An "effective inhibitory amount" of a compound of formula (I) is that amount which is effective, upon single or multiple does administration to a patient, in providing an inhibition of HIV protease. As used herein the term "effective amount" refers to an effective antiviral or inhibitory amount of a compound of formula (I). An effective amount can be readily determined by the attending diagnostician, as one skilled in the art, by the use of known techniques and by observing results obtained under analogous circumstances. In determining the effective amount or dose, a number of factors are

considerec by the attending diagnostician, including, but not limited to: the species of mammal; its size, age, and general health; the specific viral infection involved; the degree of or involvement or the severity of the viral infection; the response of the individual patient; the particular compound administered; the mode of

administration; the bioavailability characteristics of the preparation administered; the dose regimen selected; the use of concomitant medication; and other relevant

circumstances.

An effective amount of a compound of formula (I) is expected to vary from about 0.1 milligram per kilogram of body weight per day (mg/kg/day) to about 100 mg/kg/day. Preferred amounts are expected to vary from about 0.5 to about 10 mg/kg/day. In effecting treatment of a patient afflicted with a viral infection, a compound of formula (I) can be

administered in any form or mode which makes the compound bioavailable in effective amounts, including oral and parenteral routes. For example, compounds of formula (I) can be administered orally, subcutaneously,

intramuscularly, intravenously, transdermally,

intranasally, rectally, and the like. Oral administration is generally preferred. One skilled in the art of

preparing formulations can readily select the proper form and mode of administration depending upon the particular characteristics of the compound selected, the viral infection to be treated, the stage of the infection, and other relevant circumstances.

The compounds of formula (I) can be administered alone or in the form of a pharmaceutical composition in

combination with pharmaceutically acceptable carriers or excipients, the proportion and nature of which are

determined by the solubility and chemical properties of the compound selected, the chosen route of administration, and standard pharmaceutical practice. The compounds of the invention, while effective themselves, may be formulated and administered in the form of their pharmaceutically acceptable salts for purposes of stability, convenience of crystallization, increased solubility and the like.

In another embodiment, the present invention provides compositions comprising a compound of formula (I) in admixture or otherwise in association with one or more inert carriers. These compositions are useful, for example, as assay standards, as convenient means of making bulk shipments, or as pharmaceutical compositions. An assayable amount of a compound of formula (I) is an amount which is readily measurable by standard assay procedures and techniques as are well known and appreciated by those skilled in the art. Assayable amounts of a compound of formula (I) will generally vary from about 0.001% to about 75% of the composition by weight. Inert carriers can be any material which does not degrade or otherwise covalently react with a compound of formula (I). Examples of suitable inert carriers are water; aqueous buffers, such as those which are generally useful in High Performance Liquid

Chromatography (HPLC) analysis; organic solvents, such as acetonitrile, ethyl acetate, hexane and the like; and pharmaceutically acceptable carriers or excipients.

More particularly, the present invention provides pharmaceutical compositions comprising a therapeutically effective amount of a compound of formula (I) in admixture or otherwise in association with one or more pharmaceutically acceptable carriers or excipients.

The pharmaceutical compositions are prepared in a manner well known in the pharmaceutical art. The carrier or excipient may be a solid, semi-solid, or liquid material which can serve as a vehicle or medium for the active ingredient. Suitable carriers or excipients are well known in the art. The

pharmaceutical composition may be adapted for oral or parenteral use and may be administered to the patient in the form of tablets, capsules, suppositories, solution, suspensions, or the like.

The compounds of the present invention may be administered orally, for example, with an inert diluent or with an edible carrier. They may be enclosed in gelatin capsules or compressed into tablets. For the purpose of oral therapeutic administration, the

compounds may be incorporated with excipients and used in the form of tablets, troches, capsules, elixirs, suspensions, syrups, wafers, chewing gums and the like. These preparations should contain" at least 4% of the compound of the invention, the active ingredient, but may be varied depending upon the particular form and may conveniently be between 4% to about 70% of the weight of the unit. The amount of the compound present in compositions is such that a suitable dosage will be obtained. Preferred compositions and preparations according to the present invention are prepared so that an oral dosage unit form contains between 5.0-300 milligrams of a compound of the invention.

The tablets, pills, capsules, troches and the like may also contain one or more of the following adjuvants: binders such as microcrystalline cellulose, gum tragacanth or gelatin; excipients such as starch or lactose, disintegrating agents such as alginic acid, Primogel, corn starch and the like; lubricants such as magnesium stearate or Sterotex; glidants such as colloidal silicon dioxide; and sweetening agents such as sucrose or saccharin may be added or a flavoring agent such as peppermint, methyl salicylate or orange flavoring. When the dosage unit form is a capsule, it may contain, in addition to materials of the above type, a liquid carrier such as polyethylene glycol or a fatty oil. Other dosage unit forms may contain other various materials which modify the physical form of the dosage unit, for example, as coatings. Thus, tablets or pills may be coated with sugar, shellac, or other enteric coating agents. A syrup may contain, in addition to the present compounds, sucrose as a sweetening agent and certain preservatives, dyes and colorings and flavors. Materials used in preparing these various compositions should be pharmaceutically pure and non-toxic in the amounts used.

For the purpose of parenteral therapeutic

administration, the compounds of the present invention may be incorporated into a solution or suspension.

These preparations should contain at least 0.1% of a compound of the invention, but may be varied to be between 0.1 and about 50% of the weight thereof. The amount of the inventive compound present in such compositions is such that a suitable dosage will be obtained. Preferred compositions and preparations according to the present invention are prepared so that a parenteral dosage unit contains between 5.0 to 100 milligrams of the compound of the invention.

The solutions or suspensions may also include the one or more of the following adjuvants: sterile diluents such as water for injection, saline solution, fixed oils, polyethylene glycols, glycerine, propylene glycol or other synthetic solvents; antibacterial

agents such as benzyl alcohol or methyl paraben;

antioxidants such as ascorbic acid or sodium bisulfite; chelating agents such as ethylene diaminetetraacetic acid; buffers such as acetates, citrates or phosphates and agents for the adjustment of tonicity such as

sodium chloride or dextrose. The parenteral

preparation can be enclosed in ampules, disposable

syringes or multiple dose vials made of glass or

plastic.

The present invention is also directed to combinations of the HIV protease-inhibitory compounds with one or more agents useful in the treatment of AIDS, such as, for example, with known antiviral agents suitable for treating HIV 1 and HIV 2 viral infections, e.g., AZT, with or without a PNPase inhibitor, or in conjunctive therapy with DDI and a PNPase inhibitor.

The compounds of this invention may be assayed for their HIV-protease inhibition using the following published techniques.

Preparation of Retroviral Enzyme

and

Assay for Inhibition of the Protease

A) Preparation of Retroviral Enzyme

To prepare the recombinant protease, the HIV protease is expressed via E. Coli by the published work of

C. Guenet, et al., in European Journal of Pharmacology, Molecular Pharmacology Section, 172 (1989) 443-451. B) Assay for Inhibition of Recombinant Viral Protease

Inhibition of the reaction of the protease with a peptide substrate [ Ser-Gln-Asn-Tyr-Pro-Ile-Val-NH₂, Km = 1 mM] are in 50 mM Na acetate, 10% glycerol, 5% ethyleneglycol, pH 5.5, at 37°C for 1 hour. Various concentrations of inhibitor in 10 μl DMSO are added to 80 μl of assay solution and the reaction is initiated by the addition of 10 μl (1.6 μg) of recombinant protease. The reaction is quenched with 16 μl of 4 M perchloric acid. Products of the reaction are separated by HPLC (VYDAC wide pore 5 cm C-18 reverse phase, acetonitrile gradient, 0.1% trifluoroacetic acid). The extent of inhibition of the reaction is determined from the peak heights of the products. HPLC of the products, independently synthesized, provide quantitation

standards and confirmation of the product composition.

By following the techniques referenced above, as well as by utilization of other known techniques, as well as by comparison with compounds known to be useful for treatment of the above-mentioned disease states, it is believed that adequate material is available to enable one of ordinary skill in the art to practice the invention. As is true for most classes of compounds found to be useful in the pharmceutical industry, certain subgeneric groups and certain specific compounds are more preferred such as those exemplified and shown in the following charts.

₅, R₆

R₆

The following list illustrates compounds according to the present invention;

1. α,α-difluoro-γ-[[(2-(R)- [[(hydroxy)phenylacetyl]amino]-3-methyl-1-oxobutyl]amino]- β-oxo-4-(phenylmethoxy)-N-(phenylmethyl)-benzene- pentanamide;

2. [6S-(6R*, 9R*, 13S*)]-4,4,-difluoro-9-(1- methylethyl)-3,5,8,11-tetraoxo-1,13-diphenyl-6-[[4- (phenylmethoxy)phenyl]methyl]-12-oxa-2,7,10- triazatetradecan-14-oic acid, methyl ester;

3. α,α-difluoro-γ-[[3-methyl-1-oxo-2-[[(1-oxo-trans-3 phenyl-2-propenyl)amino]butyl]amino]-β-oxo-4-

(phenylmethoxy)-N-(phenylmethyl)-benzene-pentanamide;

4. α,α-difluoro-γ-[[2-[2-hydroxy-1-oxo-4-

(phenylbutyl)amino]-3-methyl-1-oxobutyl]amino]-β-oxo-4- (phenylmethoxy)-N-(phenylmethyl)-benzene-pentanamide;

5. N-[1-[[[3,3-difluoro-4-[[2-methyl-1-

[(phenylmethoxy)methyl]-propyl]amino]-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]-methyl]butyl]amino]carbonyl]-2- methylpropyl]-β-oxo-4-morpholinepropanamide;

6. [1R-(1R*,2S*)]-α,α-difluoro-γ-[[2-(R)-

[[(hydroxy)phenylacetyl]-amino]-3-methyl-1-oxobutyl]amino]- N-[2-methyl-1-[(phenylmethoxy)methyl]propyl]-3-oxo-4- (phenylmethoxy)-benzenepentanamide;

7. N-[1-[[[3,3-difluoro-4-[[2-methyl-1-

[(phenylmethoxy)-methyl]-propyl]amino]-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]- methyl]-butyl]amino]carbonyl]-2- methylpropyl]-6-(4-morpholinyl-carbonyl)-3- pyridinecarboxamide; 8. 7,7-difluoro-4,12-bis(1-methylethyl)-6,8,114trioxo- 1-phenyl-9-[[4-(phenylmethoxy)phenyl]methyl]-2-oxa-5,10,13- triazatetradecan-14-oic acid, 3-pyridinylmethyl ester; 9. [1R-(1R*,2S*)]-α,α-difluoro-γ-[[3-methyl-2-[[4-(4- morpholinylsulfonyl)benzoyl]amino]-1-oxobutyl]amino3-N-[2- methyl-1-[(phenylmethoxy)methyl]propyl]-β-oxo-4- ( phenylmethoxy)-benzenepentanamide; 10. [1R-(1R*,2S*)]-α,α-difluoro-γ-[[3-methyl-2-[[4-(4- morpholinylcarbonyl)benzoyl]amino]-1-oxobutyl]amino]-N-[2- methyl-1-[(phenylmethoxy)methyl]propyl]-β-oxo-4- (phenylmethoxy)-benzenepentanamide; 11. N-[1-[[[3,3-difluoro-4-[[2-methyl-1-

[(phenylmethoxy)methyl]-propyl]amino]-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]-methyl]butyl]amino]carbonyl]-2- methylpropyl]-4-morpholineacetamide; 12. N-[1-[[[3,3-difluoro-4-[[2-methyl-1-

[(phenylmethoxy)methyl]-propyl]amino3-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]methyl]-butyl]amino]carbonyl]-2- methylpropyl]-1H-imidazole-1-acetamide; 13. [1-[[[3,3-difluoro-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]-methyl]-4-[(2- pyridinylmethyl)amino)butyl]amino]carbonyl]- 2- methylpropyl 3-carbamic acid, 3-pyridinylmethyl ester;

14. [1-[[[3,3-difluoro-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]-methyl]-4-[(3- pyridinylmethyl)amino]butyl]amino]carbonyl]-2- methylpropyl]-carbamic acid, 3-pyridinylmethyl ester;

15. [1-[[[3,3-difluoro-2,4-dioxo-1-[[4-(phenylmethoxy)- phenyl]-methyl]-4-[(2-pyridinylmethyl)amino]butyl]- amino]carbonyl]- 2-methylpropyl]-carbamic acid, 2- pyridinylmethyl ester;

16. [1-[[[3,3-difluoro-2,4-dioxo-1-[[4-(phenylmethoxy)- phenyl]-methyl]-4-[(3-pyridinylmethyl)amino]butyl]- amino]carbonyl]- 2-methylpropyl]-carbamic acid, 2- pyridinylmethyl ester;

17. N-[4-(N-{2-pyridylmethyl)oxycarbonyl-L-valyl)amino- 2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl-pentyl]-O-(3 pyridylmethyl)-D-valinol; 18. N-[4-(N-{3-pyridylmethyl}oxycarbonyl-L-valyl)amino- 2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl-pentyl]-O-(3 pyr idylmethyl)-D-valinol;

19. N-[4-(N-{3-pyridylmethyl}oxycarbonyl-L-valyl)amino- 2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl-pentyl]-O- methyl-D-valinol;

20. N-{4-(N-{3-pyridylmethyl}oxycarbonyl-L-valyl)amino- 2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl-pentyl]-O-(2 pyridylmethyl)-D-valinol;

21. N-[4-(N-{2-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-{3- pyridylmethyl}oxy)phenyl-pentyl]-O-(3-pyridylmethyl)-D- valinol; 22. N-[4-(N-{2-pyridylmethyl}oxycarbonyl-L-valyl)amino- 2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl-pentyl]-O-(2- pyridylmethyl)-D-valinol;

23. N-[4-(N-{2-pyridylmethyl)oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-methyl-D-valinol; 24. N-{4-(N-{2-pyridylmethyl}oxycarbonyl-L-valyl)amino- 2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl-pentyl]-O- benzyl-D-valinol;

25. N-{4-(N-{3-pyridylmethyl}oxycarbonyl-L-valyl)amino- 2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl-pentyl]-O-[2-

(2-methoxyethoxy)-1-ethyl]-D-valinol; and

26. N-[4-(N-{3-pyridylmethyl}oxycarbonyl-L-valyl)amino- 2,2-difluoro-1,3-dioxo-5-(4-{2-N-morpholyl]ethyloxy)phenyl- pentyl]-O-methyl-D-valinol.

Claims (46)

1. WHAT IS CLAIMED IS: 1. A compound of the formula: - NR₅R₆ O and the stereoisomers, hydrates, isosteres and the

   pharmaceutically acceptable salts thereof wherein

   P₁ is

   wherein T is [(O)_b-W-R] and T' is [(O)_b'-W'-R'] or hydrogen, wherein each of W and W are independently

   C_1-6 alkylene or nothing,

   provided that W is C_2-6 alkylene when W is directly attached to a nitrogen atom in R,

   provided that W' is C_2-6 alkylene when W' is directly attached to a nitrogen atom in R', provided that W or W are each independently C_1-6 alkylene when R or R' are each independently an aryl;

   P₂ is C_{1 - 6} alkyl, cyclopentyl, hydroxy C_1-6 alkyl, phenyl, benzyl or 3-tetrahydrofuryl; R and R' are each independently -CH₂CHO, hydroxy C_1-6 alkyl, C_1-6 alkoxy C_1-6 alkyl, C_1-6 alkyl.

   C_1-6 alkenylene, piperazinyl, substituted piperazinyl, piperidyl, morpholinyl, pyridyl, pyrazinyl, pyrimidinyl or phenyl wherein substituted piperazinyl is

   piperazinyl substituted on one nitrogen atom thereof with CHO, C(O)NHR'₄, C_1-4 alkyl or CO₂R₄;

   R₁ is

   ^

   R₃ is C_1-6 allenyl C_1-6 alkoxy, C_1-6 alkylene, hydroxy C_1-6 alkyl, C_1-6 alkyl or OH;

   R₄ is C_1-6 alkyl, phenyl or benzyl;

   R'₄ is hydrogen or C_1-6 alkyl; R₅ is hydrogen, C_1-15 alkyl, OH, hydroxy C_1-65 alkyl, C_{1- 6} alkoxy, -CH([(CH₂)_d-O-CH₂]_x-R'₈)₂, -CH₂Si (CH₃)₂(R₃). PDL, -(C_1-6 alkylene)-OR₄, -CH(Y)(Z),

   wherein PDL is -(CH₂)_a-2-, 3- or 4-pyridyl, or p- substituted benzyloxy, wherein the substitution is with a nitro, OH, amino, C_1-6 alkoxy, hydroxy C_1-6 alkylene, or halogen; Y is C_1-15 alkyl, hydroxy C_1-15 alkyl, C_1-6 alkyl or -(CH₂)_e-C6H4-(V)_e,; Z is -(CH₂)_d-O-CHO, C_1-6 alkylene-O-(CH₂)_d-(O-CH₂-CH₂)_e-O-C_1-6 alkyl, CHO, CO₂R₄, CO₂NHR₄, -(CH₂)_d-O-(CH₂)_d,-R^, ₇, -(CH₂)_e-OR₄ or

   wherein V is OR₄ or hydroxy C_1-6 alkylene;

   provided that d'=2 when R'7 is piperazinyl, substituted piperazinyl, piperidyl or morpholinyl;

   R₆ is as defined for R₅ with the proviso that R₆ is other than hydrogen when R₅ is hydrogen, or R₅ and R₆ are taken together with the nitrogen atom to which they are attached are selected from the group consisting of;

   R₇ is CH₂OR₄, C(O)NHR₄ or CHO;

   R'₇ is piperazinyl, substituted piperazinyl, piperidyl, morpholinyl, pyridyl, pyrazinyl, pyrimidinyl or phenyl, wherein substituted piperazinyl is piperazinyl

   substituted on one nitrogen atom thereof with CHO, C(O)NHR₄, C_1-4 alkyl or CO₂R₄;

   R₈ is (H, OH) or =O;

   R'₈ is pyrimidyl, pyridyl, pyrazinyl or phenyl; a is zero, 1, 2 or 3;

   b and b' are each independently zero or 1;

   d and d' are each independently 1 or 2;

   e and e' are each independently zero, 1 or 2; and x is zero or one.
2. 2. A compound according to claim 1 wherein P₁ is >
3. 3. A compound according to claim 2 wherein x is one and P₂ is isopropyl.
4. 4. A compound according to claim 3 wherein R₁ is
5. 5. A compound according to claim 3 wherein R₁ is
6. 6. A compound according to claim 3 wherein R₅ is hydrogen and R₆ is
7. 7. A compound according to claim 3 wherein R₅ is hydrogen and R₆ is
8. 8. A compound according to claim 3 wherein R₅ is hydrogen and R₆ is
9. 9. A compound according to claim 3 wherein R₅ is hydrogen and R₆ is
10. 10. A compound according to claim 1 wherein the compound is α,α-difluoro-γ-[[(2-(R)-

    [[(hydroxy)phenylacetyl]amino]-3-methyl-1-oxobutyl]amino] β-oxo-4-(phenylmethoxy)-N-(phenylmethyl)-benzenepentanamide.
11. 11. A compound according to claim 1 wherein the compound is [6S-(6R*, 9R*, 13S*)]-4,4,-difluoro-9-(1- methylethyl)-3,5,8,11-tetraoxo-1,13-diphenyl-6-[[4-

    (phenylmethoxy)phenyl]methyl]-12-oxa-2,7,10- triazatetradecan-14-oic acid, methyl ester.
12. 12. A compound according to claim 1 wherein the compound is α,α-difluoro-γ-[[3-methyl-1-oxo-2-[[(1-oxo- trans-3-phenyl-2-propenyl)amino]butyl]amino]-β-oxo-4- (phenylmethoxy)-N-(phenylmethyl)-benzene-pentanamide.
13. 13. A compound according to claim 1 wherein the compound is α,α-difluoro-γ-[[2-[2-hydroxy-1-oxo-4-

    (phenylbutyl)amino]-3-methyl-1-oxobutyl]amino]-β-oxo-4- (phenylmethoxy)-N-(phenylmethyl)-benzene-pentanamide.
14. 14. A compound according to claim 1 wherein the compound is N-[1-[[[3,3-difluoro-4-[[2-methyl-1-

    [(phenylmethoxy)methyl]-propyl]amino]-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]-methyl]butyl]amino3carbonyl]-2- methylpropyl]-β-oxo-4-morpholinepropanamide.
15. 15. A compound according to claim 1 wherein the compound is [1R-(1R*,2S*)]-α,α-difluoro-γ-[[2-(R)- [[(hydroxy)phenylacetyl]-amino]-3-methyl-1-oxobutyl)amino]- N-[2-methyl-1-[(phenylmethoxy)methyl]propyl]-β-oxo-4- (phenylmethoxy)-benzenepentanamide.
16. 16. A compound according to claim 1 wherein the compound is N-[1-[[[3,3-difluoro-4-[[2-methyl-1-

    [(phenylmethoxy)-methyl]-propyl]amino]-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]- methyl]-butyl]amino]carbonyl]-2- methylpropyl)-6-(4-morpholinyl-carbonyl)-3- pyridinecarboxamide.
17. 17. A compound according to claim 1 wherein the compound is 7,7-difluoro-4,12-bis(1-methylethyl)-6,8,11- trioxo-1-phenyl-9-[[4-(phenylmethoxy)phenyl]methyl]-2-oxa- 5,10,13-triazatetradecan-14-oic acid, 3-pyridinylmethyl ester.
18. 18. A compound according to claim 1 wherein the compound is [IR-(IR*,2S*)]-α,α-difluoro-γ-[[3-methyl-2-[[4- (4-morpholinylsulfonyl)benzoyl]amino]-1-oxobutyl]amino]-N- [2-methyl-1-[(phenylmethoxy)methyl]propyl}-β-oxo-4- (phenylmethoxy)-benzenepentanamide.
19. 19. A compound according to claim 1 wherein the compound is [1R-(1R*,2S*)]-α,α-difluoro-γ-[[3-methyl-2-[[4- (4-morpholinylcarbonyl)benzoyl]amino]-1-oxobutyl]amino)-N- [2-methyl-1-[(phenylmethoxy)methyl]propyl]-β-oxo-4- (phenylmethoxy)-benzenepentanamide.
20. 20. A compound according to claim 1 wherein the compound is N-[1-[[[3,3-difluoro-4-[[2-methyl-1-

    [(phenylmethoxy)methyl]-propyl1amino3-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]-methyl]butyl]amino]carbonyl]-2- methylpropyl]-4-morpholineacetamide.
21. 21. A compound according to claim 1 wherein the compound is N-[1-[[[3,3-difluoro-4-[[2-methyl-1- [(phenylmethoxy)methyl]-propyl]amino]-2,4-dioxo-1-[[4- (phenylmethoxy)phenyl]methyl]-butyl]amino]carbonyl]-2- methylpropyl]-1H-imidazole-1-acetamide.
22. 22. A compound according to claim 1 wherein the compound is [1-[[[3,3-difluoro-2,4-dioxo-1-[[4-

    (phenylmethoxy)phenyl]-methyl]-4-[(2- pyridinylmethyl)amino]butyl]amino]carbonyl]- 2- methylpropyl]-carbamic acid, 3-pyridinylmethyl ester.
23. 23. A compound according to claim 1 wherein the compound is [1-[[[3,3-difluoro-2,4-dioxo-1-[[4-

    (phenylmethoxy)phenyl]-methyl]-4-[(3- pyridinylmethyl)amino]butyl]amino]carbonyl]-2- ethylpropyl]-carbamic acid, 3-pyridinylmethyl ester.
24. 24. A compound according to claim 1 wherein the compound is [1-[[[3,3-difluoro-2,4-dioxo-1-[[4-

    (phenylmethoxy)-phenyl]-methyl]-4-[(2- pyridinylmethyl)amino]butyl]-amino]carbonyl]- 2- methylpropyl]-carbamic acid, 2-pyridinylmethyl ester.
25. 25. A compound according to claim 1 wherein the compound is [1-[[[3,3-difluoro-2,4-dioxo-1-[[4-

    (phenylmethoxy)-phenyl]-methyl]-4-[(3- pyridinylmethyl)amino]butyl]-amino]carbonyl]- 2- methylpropyl]-carbamic acid, 2-pyridinylmethyl ester.
26. 26. A compound according to claim 1 wherein the compound is N-[4-(N-{2-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-(3-pyridylmethyl)-D-valinol.
27. 27. A compound according to claim 1 wherein the compound is N-[4-(N-{3-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-(3-pyridylmethyl)-D-valinol.
28. 28. A compound according to claim 1 wherein the compound is N-[4-(N-{3-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-methyl-D-valinol.
29. 29. A compound according to claim 1 wherein the compound is N-{4-(N-{3-pyridylmethyl)oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-(2-pyridylmethyl)-D-valinol.
30. 30. A compound according to claim 1 wherein the compound is N-[4-(N-{2-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-{3- pyridylmethyl}oxy)phenyl-pentyl]-O-(3-pyridylmethyl)-D- valinol.
31. 31. A compound according to claim 1 wherein the compound is N-[4-(N-{2-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-(2-pyridylmethyl)-D-valinol.
32. 32. A compound according to claim 1 wherein the compound is N-[4-(N-{2-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-methyl-D-valinol.
33. 33. A compound according to claim 1 wherein the compound is N-{4-(N-{2-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-benzyl-D-valinol.
34. 34. A compound according to claim 1 wherein the compound is N-{4-(N-{3-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-benzyloxy)phenyl- pentyl]-O-[2-(2-methoxyethoxy)-1-ethyl]-D-valinol.
35. 35. A compound according to claim 1 wherein the compound is N-[4-(N-{3-pyridylmethyl}oxycarbonyl-L- valyl)amino-2,2-difluoro-1,3-dioxo-5-(4-{2-N- morpholyl]ethyloxy)phenyl-pentyl]-O-methyl-D-valinol.
36. 36. A method of treating a patient suffering from a viral infection comprising administering to said patient an effective antiviral amount of a compound according to claim 1.
37. 37. A method of controlling a viral infection in a patient afflicted therewith comprising administering thereto an effective antiviral amount of a compound according to claim 1.
38. 38. A method of inhibiting HIV protease in a patient in need thereof comprising administering to said patient an effective inhibitory amount of a compound according to claim 1.
39. 39. A pharmaceutical composition comprising an assayable amount of a compound of claim 1 in admixture or otherwise in association with an inert carrier.
40. 40. A pharmaceutical composition according to claim 39 for the treatment of a viral infection.
41. 41. A compound according to claim 1 for use in the treatment of a viral infection.
42. 42. A compound according to claim 1 for use in inhibiting HIV protease.
43. 43. Use of a compound of claim 1, optionally in combination with a pharmaceutically acceptable carrier, for the preparation of a pharmaceutical composition for the treatment of a viral infection.
44. 44. Use of a compound of claim 1, optionally in combination with a pharmaceutically acceptable carrier, for the preparation of an HIV protease inhibitor.
45. 45. A process for the preparation of a compound of formula: -C- NR₅R₆ II

    O O

    and the stereoisomers, hydrates, isosteres and the pharmaceutically acceptable salts thereof wherein

    P₁ is

    wherein T is [(O)_b-W-R] and T' is [(O)_b'-W'-R'] or hydrogen, wherein each of W and W' are independently

    C_1-6 alkylene or nothing,

    provided that W is C_2-6 alkylene when W is direct attached to a nitrogen atom in R,

    provided that W' is C_2-6 alkylene when W' is directly attached to a nitrogen atom in R', provided that W or W' are each independently C_1-6 alkylene when R or R' are each independently an aryl;

    P₂ is C_1-6 alkyl, cyclopentyl, hydroxy C_1-6 alkyl, phenyl, benzyl or 3-tetrahydrofuryl; R and R' are each independently -CH₂CHO, hydroxy C_1-6 alkyl, C_1-6 alkoxy C_1-6 alkyl, C_1-6 alkyl,

    C_1-6 alkenylene, piperazinyl, substituted piperazinyl, piperidyl, morpholinyl, pyridyl, pyrazinyl, pyrimidinyl or phenyl wherein substituted piperazinyl is

    piperazinyl substituted on one nitrogen atom thereof with CHO, C(O)NHR'₄, C_1-4 alkyl or CO₂R₄;

    R₁ is

    R₃ is C_1-6 allenyl C_1-6 alkoxy, C_1-6 alkylene, hydroxy C_1-6 alkyl, C_1-6 alkyl or OH; R₄ is C_1-6 alkyl, phenyl or benzyl;

    R'₄ is hydrogen or C_1-6 alkyl; R₅ is hydrogen, C_1-15 alkyl, OH, hydroxy C_1-15 alkyl, C_{1- 6} alkoxy, -CH([(CH₂)_d-O-CH₂]_x-R'₈)₂, -CH₂Si(CH₃)₂(R₃), PDL, -( C_1-6 alkylene)-OR₄, -CH(Y) (Z),

    wherein PDL is -(CH₂)_a-2-, 3- or 4-pyridyl, or p- substituted benzyloxy, wherein the substitution is with a nitro, OH, amino, C_1-6 alkoxy, hydroxy C_1-6 alkylene, or halogen; Y is C_1-15 alkyl, hydroxy C_1-15 alkyl, C_1-6 alkyl or -(CH₂)_e-C₆H₄-(V)_e,; Z is -(CH₂)_d-O-CHO, C_1-6 alkylene-O-(CH₂)_d-(O-CH₂-CH₂)_e-O-C_1-6 alkyl, CHO, CO₂R₄, CO₂NHR₄, -(CH₂)_d-O-(CH₂)_d,-R'7, -(CH₂)_e-OR₄ or

    wherein V is OR₄ or hydroxy C_1-6 alkylene;

    provided that d'=2 when R'7 is piperazinyl, substituted piperazinyl, piperidyl or morpholinyl;

    R₆ is as defined for R₅ with the proviso that R₆ is other than hydrogen when R₅ is hydrogen, or R₅ and R₆ are taken together with the nitrogen atom to which the are attached are selected from the group consisting of

    R₇ is CH₂OR₄, C(O)NHR₄ or CHO;

    R'₇ is piperazinyl, substituted piperazinyl, piperidyl, morpholinyl, pyridyl, pyrazinyl, pyrimidinyl or phenyl, wherein substituted piperazinyl is piperazinyl

    substituted on one nitrogen atom thereof with CHO, C(O)NHR₄, C_1-4 alkyl or CO₂R₄;

    R₈ is (H, OH) or =O;

    R'₈ is pyrimidyl, pyridyl, pyrazinyl or phenyl; a is zero, 1, 2 or 3;

    b and b' are each independently zero or 1;

    d and d' are each independently 1 or 2;

    e and e' are each independently zero, 1 or 2; and x is zero or one, comprising oxidizing a compound of formula: - R₆

    O

    wherein all the substituents are defined as above.
46. 46. A process for the preparation of a compound of the formula: - NR₅R₆ O

    and the stereoisomers, hydrates, isosteres and the

    pharmaceutically acceptable salts thereof wherein

    P₁ is

    wherein T is [(O)_b-W-R] and T' is [(O)_b'-W'-R'] or hydrogen, wherein each of W and W are independently

    C_1-6 alkylene or nothing,

    provided that W is C_2-6 alkylene when W is directly attached to a nitrogen atom in R,

    provided that W' is C_2-6 alkylene when W' is directly attached to a nitrogen atom in R', provided that W or W are each independently C_1-6 alkylene when R or R' are each independently an aryl;

    P₂ is C_1-6 alkyl, cyclopentyl, hydroxy C_1-6 alkyl, phenyl, benzyl or 3-tetrahydrofuryl; R and R' are each independently -CH₂CHO, hydroxy C_1-6 alkyl, C_1-6 alkoxy C_1-6 alkyl, C_1-6 alkyl,

    C_1-6 alkenylene, piperazinyl, substituted piperazinyl, piperidyl, morpholinyl, pyridyl, pyrazinyl, pyrimidinyl or phenyl wherein substituted piperazinyl is

    piperazinyl substituted on one nitrogen atom thereof with CHO, C(O)NHR'₄, C_1-4 alkyl or CO₂R₄;

    R₁ is

    R₃ is C_1-6 allenyl C_1-6 alkoxy, C_1-6 alkylene, hydroxy C_1-6 alkyl, C_1-6 alkyl or OH;

    R₄ is C_1-6 alkyl, phenyl or benzyl;

    R'₄ is hydrogen or C_1-6 alkyl; R₅ is hydrogen, C_1-15 alkyl, OH, hydroxy C_1-15 alkyl, C_{1- 6} alkoxy, -CH([(CH₂)_d-O-CH₂]_x-R'₈)₂, -CH₂Si (CH₃)₂(R₃), PDL, -(C_1-6 alkylene)-OR₄, -CH(Y)(Z),

    wherein PDL is -(CH₂)_a-2-, 3- or 4-pyridyl, or p- substituted benzyloxy, wherein the substitution is with a nitro, OH, amino, C_1-6 alkoxy, hydroxy C_1-6 alkylene, or halogen; Y is C_1-15 alkyl, hydroxy C_1-15 alkyl, C_1-6 alkyl or -(CH₂)_e-C₆H₄-(V)e'; Z is -(CH₂)_d-O-CHO, C_1-6 alkylene-O-(CH₂)_d-(O-CH₂-CH₂)_e-O-C_1-6 alkyl, CHO, CO₂R₄, CO₂NHR₄, -(CH₂)_d-O-(CH₂)_d ^,-R^, ₇, -(CH₂)_e-OR₄ or

    wherein V is OR₄ or hydroxy C_1-6 alkylene;

    provided that d'=2 when R'7 is piperazinyl, substituted piperazinyl, piperidyl or morpholinyl;

    R₆ is as defined for R₅ with the proviso that R₆ is other than hydrogen when R₅ is hydrogen, or R₅ and R₆ are taken together with the nitrogen atom to which they are attached are selected from the group consisting of;

    R₇ is CH₂OR₄, C(O)NHR₄ or CHO;

    R'₇ is piperazinyl, substituted piperazinyl, piperidyl, morpholinyl, pyridyl, pyrazinyl, pyrimidinyl or phenyl, wherein substituted piperazinyl is piperazinyl

    substituted on one nitrogen atom thereof with CHO, C(O)NHR₄, C_1-4 alkyl or CO₂R₄;

    R₈ is (H, OH) or =O;

    R'₈ is pyrimidyl, pyridyl, pyrazinyl or phenyl; a is zero , 1 , 2 or 3 ;

    b and b' are each independently zero or 1;

    d and d' are each independently 1 or 2;

    e and e' are each independently zero, 1 or 2; and x is zero or one, comprising; a) oxidizing a compound of formula:

    R'₁ - O wherein R'₁ is a protected R₁ group and the remaining substituents are defined as above; b) subsequently deprotecting the oxidized product of step a.