IE54770B1 - Carbapenem intermediates - Google Patents

Description

. V.» ν' · The present invention is directed to new caibapensn derivatives in which the 2-substituent has the formulas S - A - I in which A represents a straight or branched chain alkylene group or a cyclcpentylene car cyclctexylene grcup. The compounds are useful as intermediates in the preparation of carbapenem antibacterials.

A nutter of p-lactam derivatives containing the carbapenem nucleus ^ have been disclosed in the literature. These carbapenem derivatives have been reported to possess utility as antibacterial agents and/or B-lactamase inhibitors.

The initial carbapenem canpcunds were natural products such as thienanycin of the formula: -2- 30 obtained by fermentation of Streptoavces cattleva fO.S. Patent 3,950,357). Thienamycin is an exceptionally potent broad-spectrun antibiotic vhich possesses notable activity against various Pseudomonas species, organisms vhich have been notoriously resistant to B-lactara antibiotics.

The natural product thiensnyein hat the absolute configuration 5R, 6S,· 8R. This isomer, as veil as the remaining seven thienemycin isomers, nay be obtained via total synthesis as disclosed in O.S. Patent 4,234,556. Total synthesis procedures for thienamycin are also disclosed, for example, in O.S. Patents 4,287,123, 4,269,772, 4,282,148, 4,273,709, 4,290,947 and European Patent Application 7973. A key intermediate in the disclosed synthetic methods is <8 COjpNB vherein pNB represents p-nitrobenzyl European Patent Application 38869 discloses compounds,of the formula wherein R®. R*, ancT R® are independently selected from the group consisting of hydrogen, substituted and unsubstituted: alkyl, alkenyl, and 'alkynyl, having from 1-10 carbon atoms; • cycloalkyl, cyeloalkylalkyl, and alky Icy cloalkyl, having 3-6 • carbon atoms in the cycloalkyl zing and 1-6 carbon atoms in the alkyl moieties; aryl, such as phenyl; aralkyl, aralkenyl, and aralkynyl wherein the aryl aoeity is phenyl and the aliphatic .portion has 1-6 carbon atoms; heteroaryl, heteroaralkyl, heterocyclyl and heterocyclylalkyl; wherein the substituent or substituents relative to the above-named radicals are selected from the group consisting of: -X* halo (chloro, bromo, fluoro) -08 hydroxy -Oft* alkoxy, ary lory -0CHR*R* carbaaoyloxy carbamoyl ? 12 -CHITR -HR*R2 amino HR1 amidino // HR1R*.

R -SOj Θ nit,ro NCR*)3 tri-substituted tmino. (R* group independently chosen) -4- 5 20 25 20 -C"HOR oximino -SR"*1 alkyl- and arylthio -SOjNR^R* sulfonamide -hArV ureido R^R2- aside -C0,H cazboxy * 1 -COjR carboxylate 0 -&l2 acyl acyloxy -SH percapto•?1 -SR alkyl and aryl aulflnyl 0 -^R1 alkyl and aryl sulfonyl 0 -02 cyano -Kj azido wherein, relative to the above listed substituents on R®, R2, and R*, the groups R2 and R2 are independently selected from: hycrogen, alkyl, alkenyl, and alkynyl, having from 1-10 carbon . atoms; cycloalkyl, cycloalkylalkyl, and alkylcycloalkyl, having 25 3-6 carbon atcms in the cycloalkyl ring and 1-6 carbon atoms in the alkyl moieties; aryl, such as phenyl; aralkyl, aralkenyl, and aralkynyl wherein the aryl moiety is phenyl and the aliphatic portion has 1-5 carbon atoms; heteroaryl, heteroaralkyl, hetero-cyclyl and heterocyclylalkyl and wherein the hetero atom or atoms 20 in the above-named heterocyclic moieties are selected from the -5- group consisting of 1-4 oxygen, nitrogen or sulphur atoms and wherein the alkyl moieties associated with said heterocyclic moieties have 1-6 carbon atoms, {See also European Patent Applications 1627, 1628, 10317, 17992, 37080, 37081 5 and 37082) .

European Patent Application 38,869 mentioned above discloses synthesis of the carbapenea derivatives via -intermediates of the general formula 15 wherein R® and R^ are as defined above and Rj* is a readily removable carboxyl protecting group. Also disclosed as intermediates are compounds of the formula 20 -X Γ*— 25 wherein X is described as a leaving group.

A more ocnprehensive review of know carbapenem compounds is to be found in our published British Patent Application No 2119371, from 30 which the present application is divided. Our published Application No 2119371 claims -6- a novel series of carbapenem derivatives characterised by a 2-substituent of the formula: -S—A—N J wherein A is straight or branched chain alkylene or is a cyclo-pentylene or cyclchexylene group and e represents a quatemized nitrogen-containing aromatic heterocycle. Mare specifically, GB 2119371 provides carbapenem derivatives of the formula: wherein R® is hydrogen and K* is hydrogen; a substituted or unsubstituted alkyl, alkenyl or alkynyl grcup, having 1 to 10 carbon atans; a cycloalkyl or cycloalkylalkyl group, having 3 to 6 carbon atans in the cycloalkyl ring and 1 to 6 carbcn atans in the alkyl group; phenyl; an aralkyl, aralkenyl car aralkynyl group wherein the aryl group is phenyl and the aliphatic group has 1 to 6 carbcn atans; a heteroaryl, heteroaralkyl, heterocyclyl or heterocyclylalkyl group wherein the hetero atcm or atoms in the above-named heterocyclic groups are 1 to 4 oxygen, nitrogen or sulfur atans and the alkyl groups associated with the heterocyclic grajps have 1 to 6 carbon atoms; wherein the substituent or substituents relative to the above-named groups are: -7- C, to C, alkyl optionally substituted by 1 o i amino, halo, hydroxy or carboxyl halo -OR3 -ocnr3r4 S 3 4 -CNR R -nr3r4 /NR3 ArV -s'o2nr3r4 * 3 4 -NHCNRR 0 3// 4 R CNR- -CO?R3 »0 -OCR -SR3 ‘-If 0 II 9 Ύ 0 -cs "H3 3 -OSOjR -OSti?R3 -N^SO^R4" -8- 5 -nr3c=nr4 3 4 -nroo2r -no2 wherein, relative to the above-named substituents, the groups R3 and R are each independently hydrogen; an alkyl, alkenyl or alkynyl group having fran 1 to 10 carbon atoms; a cycloalkyl, cycloalky la Iky 1 or alklycycloalkyl group having 3 to 6 carbon atans in the cycloalkyl 10 ring and 1 to 6 carbon atans in the alkyl groups; phenyl; an aralkyl, aralkenyl or aralkynyl wherein the aryl group is phenyl and the aliphatic portion has 1 to 6 carbon atcms; or a heteroaryl, heteroaralkyl, heterocyclyl or beterocyclylalkyl group wherein the hetero atan or atans in the‘above-named heterocyclic gaps are 1 to 4 oxygen, 15 nitrogen or sulfur atoms and the alkyl groups associated with the 3 4 heterocyclic groups have 1 to 6 carbon atoms, or R and R taken together with the nitrogen to which at least one is attached may form * o a 5- or 6-unentered nitrogen-containing heterocyclic ring; R is as 3 1 defined far R except that it is other than hydrogen; or wherein R O and R taken together represent C^-C^Qalkylidene or alkylidene substituted by hydroxy; A is cyclcpentylene, cyclotexylene or C--C, Z 0 alkylene optionally substituted by one or more C.-C. alkyl groups; 2 α ’ R is hydrogen, an anionic charge or a conventional readily removable 2 carboxyl protecting group, providing that when R is hydrogen or a 25 protecting group, there is also present a counter anion; and represents a substituted or unsubstituted ncno-,bi- or polycyclic aromatic heterocyclic radical containing at least cne nitrogen in the 30 ring and attached to A through a ring nitrogen, thereby fanning a quaternary annonium group . The compounds may be as pharmaceutically acceptable salts thereof.

V The compounds of formula I are potent antibacterial agents or intermediates useful in the preparation of such agents.

The present invention provides novel intermediates of the formula 5 fYM H -^ 2· COOR 21 2« 10 vhertin R is a conventional readily removable earboxy* 1 ft protecting group and R , R and λ are as defined above.

Also included in the invention are processes for . preparing the novel carbapenea intermediates. 20 The novel compounds of general formula II above contain the carbapenem nucleus and may thus be named as l-carba-2-penem-3-carboxylic acid derivatives. Alternatively, the eorsounds may be considered to have the basic structure -10- and named as 7-oxo-l-azabieyelo(3.2.0)hept-2-ene-2-carboxylie acid derivatives. While the present invention includes compounds wherein the relative stereochemistry of the 5,6-protons is cis as well as trans. the preferred 5 compounds have the 5R,£S (trans) stereochemistry as in the ease of thienamycin.

The compounds of formula Π may be unsubstituted in the E-position or substituted by substituent groups previously disclosed for other carbapenem derivatives. *· a i · 10 More specifically, R may be hydrogen and R may be hydrogen or a non-hydrogen substituent disclosed, for example, in European Patent Application 36,869 (see definition of Rg). Alternatively, R® and R* taken to- · gether may be C^-C^g alkylidene or Cj-C^g alkylidene 15 substituted, for example, by hydrcxy. 1 8 To elaborate on the definitions for R and R : (a) The aliphatic "alkyl*, "alkenyl" and "alkynyl· groups may be straight or branched chain having 20 1-10 carbon atoms; preferred are 1-6, most preferably 1-4, carbon groups; when part of another substituent, e.g. as in cycloalkylalkyl, or heteroarelkyl or ar-alkenyl, the alkyl, alkenyl and alkynyl group preferably' contains 1-6, most preferably 1-4, carbon atoms. (b) "heteroaryl* includes mono-, bi- and polycyclic aromatic heterocyclic groups containing 1-4 Ο, N or 5 atoms; preferred are 5- or 6-raenibered heterocyclic rings such as thienyl, furyl, thiediazolyl, oxa- 30 diarolyl, triaeolyl, isothia2olyl. thiazolyl, iraid- · atolyl, isoxazolyl, tetrazolyl, oxazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrrolyl, pyrazolyl, etc. -11- (c) "heterocyclyl* includes mono-, bi- and polycyclic saturated or unsaturated non-aromatic heterocyclic groups containing 1-4 0, H or S atoms; preferred are 5- or 6-raembered heterocyclic rings such as morpholinyl, piperaxinyl, piperidyl, pyrarolinyl, pyrazolidinyl, imidazolinyl, imidaxolidinyl, pyrrolinyl, pyrrolidinyl, •tc. (d) "halo* includes chloro, bromo, fluoro and iodo and -is preferably chloro or bromo.

She term ’conventional readily removable carboxyl protecting group* refers to a known ester group which has been employed to block a carboxyl group during the chemical reaction steps described below and which can be removed, if desired, by methods which do not result is any appreciable destruction of the remaining portion of the molecule, e.g. by chemical or enzymatic hydrolysis, treatment with chemical reducing agents under mild conditions,'irradiation with ultraviolet light or catalytic hydrogenation. Examples of such ester protecting groups include benzhydryl, .p-nitrobenzyl, 2-naphthylaethyl, allyl benzyl, trichloroethyl, silyl such as trimethylsilyl, phenacyl, p-methoiybenzyl, aeetonyl, o-nitrobenzyl, 4-pyridylmethyl and C^-Cg alkyl such as methyl, ethyl or t-butyl. Included within such protecting groups are those which axe hydrolyzed under physiological conditions such as pivaloyloxymethyl, acetcxymethy 1, phthalidyl, indanyl and methoxymethyl. Particularly advantageous carboxyl protecting groups are p-nitrobenzyl which may be readily removed by catalytic hydrogenolysis and allyl which can be removed by Pd(P0j)^- catalyzed reaction.

Compounds of formula I wherein R^ is hydrogen, an anionic charge or a physiologically hydrolyzable ester group together with pharmaceutically acceptable salts thereof arc useful as antibacterial agents· The 'remaining com-5 pounds of formula I are valuable intermediates which can be converted into the above-mentioned biologically active compounds. λ preferred embodiment of the present invention comprises compounds of formula II wherein- R8 is hydrogen 10 and R" is hydrogen; CH^CHj- <3 ca- ra or Among this -subclass, the preferred compounds are those in which R is most preferably compounds having the absolute configuration SR, 6S, 8R.

Another preferred embodiment comprises cespounds of formula II in which R1 and R8 taken together fora an · aUeylidene radical of the formula EOCH, c= 25 Tha alkylene or cycloalkylene substituent λ in the compounds of Formula II may be C^-Cg alkylene (straight chain) optionally substituted by one or more (preferably 1 or 2) C^-C^ alkyl groups or it may be cyclopentylene or cyclohexylene. The alkylene A substituent is preferably straight or branched 30 chain alkylene of from 2 to £ carbon atoms. A cycloalvylene A substituent is preferably cyclopentylene of the formula -13- / HC / \ / H,C HCT 21 I h2c.

CH. or cyclohexylene of the formula 5 /< H_C HC' 10 Ί IVs/ H- A preferred embodiment comprises those carpamds in which A is 15 -CHCH-- CH. or - (CHj) n~ in which n is 2, 3 ar 4 and a particularly preferred 20 embodiment comprises those compounds where A is -CHjCHj-, Ό -CH,CH,CB,-, -CHCH-- or 2 2 2 | 2 CH- -14- The carbapenem derivatives of general formula I maybe prepared from starting materials of the formula: X 8 o' wherein R and R are defined above and wherein κ 10 represents a conventional readily removable, carboxyl protecting groups. Compounds of formula III have been disclosed, for example, in European Patent Application 38,869 (compound 2) and may be prepared by the general methods described therein.

One process for preparing compounds I from starting materials III may be summarized by the following reaction scheme: -15- ,8 f ~"Π COOR J—v- III m ΐιιίι IV »P(0C6H5)2 COOR -16- tj < ** Η -λ-CB OOR £ V optional fle-bloeking X© * To elaborate cn the above process, starting material III is reacted in the inert organic solvent such as methylene chloride, acetonitrile or dimsthylformamide with about an equimolar amount of diphenyl chlorcphosphate in the presence of a base such as diisoprcpyl-ethylamine, triethyl amine, 4-dirrethylamincpyridine or the like to give intermediate IV. The acylation to establish the diphenylphosphorylaxy leaving group at the 2-positian of intermediate III is advantageously carried out at a temperature -17- of from about -20* to +40· C, most preferably at about 0*C. Intermediate IV may be isolated if desired, but is conveniently used for the next step without isolation or purification.

Intermediate IV is next converted to intermediate V by a conventional displacement reaction. Thus, intermediate IV pay be reacted with approximately an equimolar amount of a mercaptan reagent of the formula HS-A-CB wherein A represents cyclopentylene, cyclohexylene or C^-C^ aUcylene optionally substituted by one or more alkyl groups in an inert organic solvent_such as dioxane, dimethylformamide, diaethylsulfoxide or acetonitrile and in the presence of a base such as diisopzopylethylaaine, triethylamine, sodium hydrogen carbonate, potassium carbonate or 4-dimethylaninopyridine. Tbe temperature for the displacement is not critical, but an advantageous temperature range is from about -4Q*C to 25*C. Host conveniently, the reaction is carried out with cooling, e.g. at about 0*C.

Intermediate Vis then acylated with methanesulfonyl chloride or-a functional acylatiag equivalent thereof such as methanesulfonic acid anhydride in an inert organic solvent and in the presence of base.to provide tbe methanesulfonyloxy leaving group of intermediate VI. The acylation is carried out in an inert organic solvent such as tetrahydxofuran, methylene chloride, acetonitrile or dimethylformamide and in the presence of a suitable base such as diisopropylethylanine, triethylamine, 4-dimethylamincpyridine,*and the like. The reaction may be carried out over a wide temperature range, e.g. -40*C to +40*C, but is most advantageously conducted with cooling, e.g. at about -30*C to -40*C.

Intermediate VI is next subjected to a displacement reaction so as to provide in novel intermediate II the iodo leaving group. This particular group has been found to greatly facilitate preparation of the carbapenem end-products of formula I.

The displacement of the methanesulfonyloxy leaving group ii carried out by reacting intermediate VI with a source of iodide ions in an inert organic solvent such as acetone, dimethyl-5 formamide or dime thyliulfoxide. Any compound which ionizes in the solvent employed to provide iodide ions may be used, e.g. an alkali metal iodide such as Nal or XI. The temperature for the displacement is not critical, but temperatures of room temperature or above axe most advantageous for achieving completion 10 of the reaction in a reasonable time period. The source of iodide ions is employed in an amount so as to provide approximately an equivalent or excess of iodide ion relative to intermediate VI. , Preparation.of the desired carbapenen derivatives of 15 formula I is carried out by a nucleophilic displacement of the iodr leaving group of intermediate II by the desired nitiogea-tontaining heteroaromatic nucleophile Intermediate II is reacted vith at'least an equivalent, preferably U excess, of the desired heteroaryl reagent in an inert organic solvent and in the presence of silver ion. Suitable inert organic solvents include, for example, tetrahydrofuran, dioxane, 25 methylene chloride, diglyme, dimethoxyethane, and the like.

Any silver'compound which substantially ionizes in the solvent . to give silver ions and an inert anior. may be used as the source of silver ion, e.g. AgClO^. Generally, we prefer to use approximately an equivalent amount (relative to intermediate II) of 30 silver ion to facilitate the displacement. The reaction may be carried out over a vide temperature range, e.g. from about -25* to about -fiS’C, but is most preferably conducted at around 0*C.

Intermediate 1' will have e counter anion (derived from the filver aalt used) associated with it which may at this stage be substituted by a different counter anion, e.g. one which is pharmaceutically acceptable, by conventional procedures. Alternatively, the counter ion may be subsequently removed during the· de-blocking step.

The de-blocking step to remove the carboxyl protecting 2· group A of intermediate 1' is accomplished by conventional procedures such as solvolysis, chemical reduction or hydrogenation. Where a protecting group such as p-nitzobenzyl, benzyl, benzhydxyl or 2-naphthylmethyl is used which can be removed by catalytic hydrogenation, intermediate X* in a suitable solvent such as dioxane-water-ethanol, tetrahydrofuren-aqueous dipotassium hydrogen phosphate-isopropanol or the like may be treated under a hydrogen pressure of from 1 to 4 atmospheres in the presence of a hydrogenation catalyst such as palladium on charcoal, palladium hydroxide, platinum oxide or the like at a temperature of from „ 2* 0 to 50 C for from about 0.24 to 4 hours. When R is a group such as o-nitrobenzyl, photolysis may also be used for deblocking. Protecting groups such as 2,2,2-trichloroethyl may be removed by mild zinc reduction. The allyl protecting group nay be removed with a catalyst comprising a mixture of a palladium compound and triphenyl phosphine in an aprotic solvent such as tetrahydrofuran, diathyl ether or methylene chloride. Similarly, other conventional carboxyl protecting groups may be removed by methods known to those skilled in the art. Finally, as mentioned above, compounds of formula X' where R is a physiologically hydrolyzable ester such as acetoxymethyl, phthalidyl, indanyl, pivaloyloxymethyl, methoxymethyl, etc. may be administered directly to the host without de-blocking since such esters "«re hydrolyzed in vivo under physiological conditions. -20- 5 1 8 It will be understood that where the R and/or R substituent or the heteroaranatic nucleophile attached to substituent A caitain a functional group which might interfere with the intended course of reaction, such group may be protected by a conventional blocking groq> and then subsequently de-blocksd to regenerate the desired functional group. Suitable blocking groups and procedures for introducing and rsieving such groups are well known to those skilled in the art.

In the case of certain compounds, of formula II having a cyeloalkylene or branched alkylene A substituent, one or more additional assymmetric carbon atoms may be created which result in formation of diastereoisomers. The present invention includes mixtures of such diastereoisomers as well as the individual purified diastereoisomers.

The following Exanples illustrate but do not limit the scope of the present invention. Ihe Exanples also illustrate the preparation of the end products I from the intermediates II of tte present invention. In the Exanples, the concentration of aqueous H^PO^ is expressed in terms of percentage by volume, whilst references to 25 10% Pd on charcoal are in terms of weight. -21- w Example 1 Preparation of 3-12-{l-Pyridinium)ethvlthio1-6c~iI-(R)-hvdroxyethvl]-7-oxo-l-azabicvclo (3.2.0)-hcpt-2-cnc-2-carboxylate λ·. p-Nitrobenzyl 3-(2-hy0roxyethylthio)-60-fl-(R)-hydroxyethy 1]-7-oxo-l-azabicyclo -(3.2.0)hcpt-2-ene-2-carboxylate OH -22- A solution of 1.69 g (4.15 nmole) of p-nitrobenxyl *·- [1-(R) -hydroxyethyl]-3,7-dioxo-l-azabicyelo (3.2.0)hep-tane-2-carboxylate (Jl) in 20 ml of acetonitrile was cooled to 0*C under a nitrogen atmosphere, λ solution of 726 mg (7.It 5 mmole) of diisopropylethylamine in 2 ml of acetonitrile was added followed'by a dropwise addition of 1.51 g (5.E0 mmole) of diphenyl chlorophesphate in 12 ml of acetonitrile over a period of 3 minutes. The resulting solution was stirred at 0* for 20 minutes to provide p-nitrobenzyl 3-(diphenylphosphozyloxy)-6a-10 (1-(R)-hydroxyethyl]-7-exo-l-azabicy clo (3'.2.0)hept-2-ene-2-carboxylate. To this solution was added a solution of 726 mg (7.11 mmole) of diisopropylethylamine in 2 ml of acetonitrile followed'by a solution of 435 ng (5.63'mmole) of 2-meccapto-ethanol in 2 ml of acetonitrile. The reaction solution was stirred at 0*C for 3 hours and then diluted with 200 ml of ethyl acetate and washed with 200 ml of water, 100 ml of 20t aqueous BjPOj, and brine. Evaporation of the dried (MgSOj) solution gave a semisolid which was triturated with methylene chloride end filtered to yield 1.2 g (618 yield) of title product 2 as a 20 whitt amorphous solid. ΝΜΚ (DMS0-d6) 6:1.20 (3B, d, J-6.0 Hz), 2.9-3.2 (9H,m) , 5.22(12, d, J-8.5 Hz) and 8.23 (2B, d, J-8.S Hi); ir (KBr) ymax: 3500, 1770 and 1700 ea_1s Anal. Calc'd for CleH20M2°7Ss C, 52.53; H, 4.94; 8, 6.86; S, 7.85. Found: C,· 52.83; Η, 4.90·; 8, 6.42; 25 S, 8.31.

A. p-Mitrobenzyl 3-(2-methanesuifonvloxyethvlthio)- 6a-Tl-(R)-hydroxyethyl)-7-exo-l-azabicvclo(3.2.0)heut— 2-ene-2-ca;boxylate ce -23- V 7 s, TO a solution of 4.2 g (10.3 nmole) of 2^.in 200 al of tetrahydrofuran there was added at -40*C 1.3 '9 (11.3 nmole) of methanesulfonyl chloride followed by a dropwise addition of 1.2S 9 (12.4 nmole) of triethylamine in 5 ml of tetrahydrofcren.

The reaction mixture was stirred for 5 hours at -40*C, then stirred for 2 hours-at -30*C under a nitrogen atmosphere and then poured into a mixture of ethyl acetate (700 al) and S% aqueous phosphoric acid (1000 al). The organic layer was washed with brine, dried over HgSOj', filtered and condensed to a syrup.

This material was purified by silica gel column chromatography [elution with methylene chloride-ethyl acetate (3:1 v/v)] to give 3.55 g (75% yield) of the title compound as e white amorphous solid.

NHR (CDCI3) i: 1.25*'(3H,'d, J-6.0 Hr), 3.05 (3H, s), 3,06-3.40 15 (SB, a), 4.05-4.40 (4B, a), 5.25 (IB, d, J-14.0 Bz), 5.50 (IS, d, J-14.0 Bz), 7.70 (2B, d, J-8.5 Bz) and 1.23 (2B, d, j-S.5 Bz); it (SB t) γη ax: 3400, 1770 and 1600 ’eaT1. Anal. Calc1 d for C, 46.90; B, 4.56*; H, 5.76, JTounC: C, 46.52; B, 4.32; N, 5.91.

C. p-Hitrobenzyl -3-(2-iodoethvlthio)-6a-[1-(10-' hvdroxvethvn-7-oxo-1-trabicyclo (3.2.0 )heot-2-enc-2-cexboxvlete OS -24- 4 S4 7 λ solution of 350 mg (O'.72 nmole) of intermediate 3 and 216 mg (1.4 nmole) of sodium iodide in 20 ml of acetone was heated at reflux for 4 hours. Evaporation of the acetone Save a white amorphous solid which was suspended in ether -(10 ml)-5 water (10.nl). Filtration of the white solid and vacuum drying produced 300 mg (801 yield) of the title compound 4 u a white amorphous powder.

HMR (DKSO-dS) 6: 1.18 (3H, d, J-6.0 Zz), 3.20-3.60 (7H, a), 3.j0_ 4.25 (2H, m), 5.10 (IS, d, J-S.S Hr), 5.25 (IX, d, J-12.0 Hr), 10 5.45 (1H, d, J-12.0 Hz), 7.70 (2H, d. J-8.5 Hr), and 8.27 (2H, d, J-8.5 Hz);,ir (Mr) yeax: 3500, 1768 and 1700 caf1; Anal. Calc'd for ClgH19H2Og3s C, 41.71; H, 3.70; H, 5.41; X, 24.48. Found: C, 42.10; B, 3.75; H, 5.57; Z, 23.20. 0. 3- (2-(l-Pyridinj-nm) ethylthio)-6e- (1-(R) -hydroxyethyl)- 7-oxo-1-azahicyclo (3.2.0)hept-2-ene-2-carboxvlate \ y OB To a solution of 327 mg (0.S3 nmole) of intermediate < in 20 ml of tetrahydrofuran there uas added at 0*C 100 mg {1.26 imole) oi pyridine followed by a solution of 139 ng (0.C7 mmole) of silver perchlorate in 1 nl of tetrahydrofuran. The mixture was stirred for 1 hour at 0*C and then for 2 hours at room temperature. The solvent was evaporated in vacuo affording compound 5 as a slightly yellow gun which was digested with 300 mg of C£LITE*to give an amorphous solid. IR (KBr) ynax: 3400,.1770. 1700 and 1100 os 1 Without, any further purification, compound 5 was hydrogenated.

Thus, to a -suspended mixture of compound 5 in 50 ml of ether and 50 ml -of tetrahydrofuran there was added a solution of.12S ng (1.26 nmole) of potassium bicarbonate and 110 mg (0.(3 mncle) of dibasic potassiea'phosphate in 50 ml of water; Then, 350 mg of 10% palladium on charcoal was added and the mixture was hydrogenated at 40 psi on the Tars shaker for 60 minutes.

The mixture was then filtered and the catalyst was washed with water (2 x 10 ml) . The combined filtrate and washings were extracted with ether (2 x 100 ml) and then lyophilizcd to give a yellow powder. The crude yellow powder was purified on a BONDAPAX reverse phase column (8g)- (Waters Associetes) , eluting with water under 8.psi pressure-. Each 15 ml fraction was assayed by high pressure liquid chromatography, and fractions having as ultraviolet absorption at 1 300 am were collected and lvcphi- 2M9C * Used to give 40.mg (19%'yield based on compound 4) of the title product £.as a white amorphous solid.

NHP. (D?0) 6: 1.20 (3B, d, J-6.0 Bz), 2.90-3.70 (?B, m),. 3.75-4.20 (2E, m) and.7.70-8.80 (SB, m); ir (XBr) γη ax; 3400, 17(0 and 1590 cmTl; Anal. Calc'd for C^gB^gNjO^SJBjO: C, 51.89; B, 5.40; H, 7.55. rounds C, 49.91} a,-5.08; N, 7.11. 07 lrTr (CHjCSjOB) 296 nn (c-7696).

CEUTE is a Trade Mark Example 2 Preparation of 3-[3.-(l-Pyridiniura)propylthio]- 6a-[1-(R)-hydroxyethyll-7-oxo-l-azabicyclo (3.2.0)- hept-2-ene-2-carboxylate ,S-CH2CH2CB2-N '-D Γ-Nitrobenrvl 3-(3-hvdroxvpropylthio)-6a-fl-(R) - · hydroxyethyl]-7-oxo-1-azabicyclo (3.2.0)-hept-2-ene-2-carboxylate 0 1) flap) „pci v 2) HSCE2CH2CH20H 0H, -27- 7 7, A solution of 926 mg (2.66 mmol) of p-nitrobenzyl 6 (1- (R)-hydroxyethyl]-3,7-dioxo-l-azaMcyclo(3.2.0)-heptane-2-carboxylate (2) in 15 ml of acetonitrile was cooled to -10* under a nitrogen atmosphere. A solution of 349 mg 5 (2.7 mmol) of diisopropylethylamine in 1 ml of acetonitrile was added followed by a dropwise addition of 725 mg (2.0 nrol) of diphenylchlorophosphate in 0.7 ml of acetonitrile over a period of 2 minutes. The resulting solution was stirred at -10* for 15 minutes to provide p-nitrobenzyl-3-(diphenyl-i0 phosphoryloxy) -6 a-11- (R)-hydroxy ethy1] -7-oxo-1-eztbicyclo [3.2.0] hept-2-ene-2-carboxylate. To this solution was added a solution of 326 mg (2.8 mmol) of diisopropylethylamine in 1 ml of acetonitrile followed^ by’a solution of 273 mg (3.0 mmol) of 3-mercaptopropanol in 0.5 ml of acetonitrile. The reaction was stirred for five hours at room temperature and then overnight at 5*. Reaction was diluted with 100 ml of ethylacetate and washed with 100 ml of wafer and then brine. Condensation of dried (MgSO^) solvent to about 5 ml of volume produced white crystals which were Washed with 20 ether to give 830 mg (74%) of the title compound (3) as white crystals; m.p. 142-144*C.

NMR (DMSO-dg) 5:1.20(3H, d, J=6.0 Hz) 1.5-2.0(2B, m) , 2.8-3.6ΠΗ, m) , 4.60(IB, t, J=S.O and 5.0 Hz), 5.1(1H, d, J=5.0 Hz), 5.25(1H, d, J=14.0 Hz), 5.50(1H, d, J=14.0 Hz) 25 7.70 ( 2H, d, J=8.5 Hz) and 8.23(2H, d, J=8.5 Hz); i; (kBr) ymax: 3400, 1770, and 1600 cm Anal. Calc’d for C19H22N207S·1/2H20; C, 52.90; H, , 5.33; N, 6.49; S, 7.42. Found i c, 53,10; H, , 5.08; N, 6.61; $, 7.65. -28- Β. p-Nitrobenzyl 3- (3 -iodopropylthio)~6α~[1-(R)-hydroxyethyl)-7-oxo-l-azabicyclo(3.2.0)hept-2-ene-2-carboxylate TsCl sch2ch2ch2oso2 COjpNB -o- CH. ch2ch2ch2i Nal To a solution of 810 mg (1.91 nmol} of 3 in 20 ml of dry tetrahydrofuran was added 400 mg (2.10 mmol) of p-toluenesulfonylchloride followed by 268 mg (2.20 mmol) of dimethylamino pyridine and the mixture was stirred for two 5 hours at room temperature under a nitrogen atmosphere. Reaction mixture was then poured into ethylace-tate-ice water The organic layer was washed with 40% Η,^ΡΟ^ Μ(3 dried over MgSO^. Evaporation of dried solvents gave the tosylate £ as a yellow oil which was converted into the iodo carpound 5 10 without any further purification. The crude £ was dissolved in 30 ml of acetone, 1.5 g (10 mmol) of sodium iodide was added and the mixture was stirred sixteen hours at room temperature. Reaction mixture was poured into ethylacdtate-water. Evaporation of dried (MgSO^) solvent cave a yellow 15 syrup which was purified by silica gel column chromatography -29- ο» * - ν / i ν lelution with methylene chloride-ethylacetate (9:1 v/v) to give 142 mg (18.51 yield) of the title compound as a white amorphous powder.

NMR (acetone-dg) 6:1.25(3H, d, J=6.0 Hr), 2.7-3.5(7H, 5 m), 4.0-4.4(2H, m), 5.30(1H, d, J=14.0 Hr), 5.65(1H, d, J=14.0 Hz), 7.80(2H, d, J=8.5 Hz), 8.30(2H, d, J=8.5 Hr); ir (KBr) ymaxs 3500, 1770 and 1600 cnT^.

C. 3- [3-(l-Pyridinium)proDylthio]-6a- (1-(R) -hydroxyethyl]-0 7-oxo-1-arabicyclo (3.2.0)-hept-2-ene-2-carboxylate 15 5 To a solution of 140 mg (0.3 mmol) of the iodo compound 5 in 5 ml of dry tetxahydrofuran was added 50 mg (0.6 mmol) of pyridine followed by a solution of 100 mg 30 (0.5 mmol) of silver perchlorate in 1 ml of tetrahydrofuran.

The mixture was stirred for two hours at room temperature and then the solvent was evaporated in vacuo affording compound 6 as a slightly yellow gum.

IR (KBr) yrnax: 3400, 1770, 1600 and 1100 cm Without" 35 any further purification, compound £ was hydrogenated. -30- 5 4 V", Thus, to a suspended mixture of compound £ in 20 ml of ether and 20 ml of tetrahydrofuran there was added a solution of 30 mg (0.3 mmol) of potassium bicarbonate and 52 mg (0.3 mmol) of dibasic potassium phosphate in 20 ml 5 of water. Then, 100 mg of 10( palladium on charcoal was added and the mixture was hydrogenated at 40 psi in the Par shaker for sixty minutes. The mixture was then filtered and the catalyst was washed with water (2x5 ml). The combined filtrate and washing were extracted with ether •10 ( 2 x 5 ml) and then lyophilized to give yellow solids.

The crude material was purified on a C18 BONDAPAX reverse phase column (8 g) (Waters Associates), eluting wiUj water under 8 psi pressure. Each 10 ml fraction was assayed by high pressure liquid chromatography, and fractions having 15 an ultraviolet absorption at Xmax 300 nm were collected and lyophilized to give 8 mg of the title compound as a slightly yellow glassy powder.

NMR (DjO) 6:1.25(3H, d, J=6.5 Hz), 1.5-1.8(2H, m), 2.2-3.70(7H, m), 4.0-4.3(2H, m), 7.9-8.9(m, 5H); 20 ir (KBr) ymax: 3400, 1760 and 1590 cm-1. UV Ira ax (HjO) 294 nm (£=6,082), 265 nm (£=6,317).

( I Examples 3-16 The cxiipounds listed below may be prepared by the procedure of Example 1 or 2 by reacting the appropriate intermediate of the formula ··. κ ε-λ-ι COj-p-nitrobenryl 10 with the appropriate heteroaromatic nucleophile and then removing the p-nitroben2yl carboxyl-orottciing group by catalytic hydrogenation. ft, , 2 J*. . . ^ & i i \J Examde 3 Preparation of 3- [2- (1-(3,5-(3imethylpyridiniuxn) ethylthioll-6c- [1- (R) -hydroxyethyl]-7-oxo·-!-5 azaMcyclo(3.2.0. )hept-2-ene-2-carboxylate Example 4 (SB· 6S1 -3-1 IS- (3-hyiroxyatthvlPVT<£ini’o) tthvllrhlol-6- J (})-J-ladre?yetJiyl1-7-o«o-l-»t«bl'evelef3;i.01heot-?--nt-;-e>rbe>cvl«te 20 -33· Example 5 (SR ,65).-3-1 2-{4-hydroxyeethylpyrid£nio)ethyl thio)-6r II- (BHiy6xoxyethyU-7-oxo-l-«zabicyclo 13.2.0)hept-2-ene-2-e»rbo«ylate Example 6 of 3-t2-(l-(2-inethvlpvridlnium))-ethylthio]-6a-tl-(B)~hydroxvethyl]-7-oxo-l->zeblcyclo(3.2.0)hect-2-ene-carboxvlate Example 7 3-f2-(l-M-methvlpyridinlural )-ethylthio)-6a-fl(R)-hvdroxyethyll-7-oxo-l-aiabicyclo(3.2.0)hept~2-ene-2-earboxylate 'cco' Example 8 (SB) 3-t2-(4-methylthiopyridlnio)-ethylthio]- (6S) - [ (1R)-hvdroxvethyll-7-oxo-l-aiablcyclo[3.2,0)hept-2-ene-2-earboxylate Example 9 3— f 2—(3-methoxy-l-evridinium)ethylthlol-6a-f1(B)-hydroxyethvl]-7-oxo-l-azabicyclo(3.2.0)- Example 10 (SR,65)-3-1U-(3-atthylthlopyrldlnlo)ethylithloj-6-11- (Ryhytooxyethyll -7-oxo-l-aaaMcvclo f 3.3. Oihtot- i-tne-i-carioxyla te •Example 11 3-[2-(1-(2,6-dimethyIpyridinium) -ethylthio]-6b-II-(B) -hydroxyethy1)-7-oxo-l-ataMcyclo(3.2.0)hept-2-ene-2-carboxvlate -36- 3 47 7 ύ Example 12 (5B. 65)-3-f2-(2-octbTltfclo-3-methvlimidazolio) ethyl-thiol-6-[1-(R) -hvdroxy-ethvll-7-oxo-l-azabicyclo[3.2.0lhept-2-ene-2-carboxylate Example 13 (5B. 6S)-3-t 2-(3-amlnopyridinio)ethvl-thio]-6-[l- -37- v> Example 14 v> (SJti 65 J 3-11- (S) -eethyl- 2- (l-pyriiij lua) ethy lthie] -6*tl-lR>-kydroxy«thyll-7-oxo-l-a2»Mcyelo(3.!.P)bept-2-*nt-2'caiboxylat« (5b, 6S) 3r (1- (R) -B»thy1-2- (l-pyri4iniua) *thylthio) -ff- f 1- (X) -hydrsxyethylj -7-oxo-l-as*)bicyclo (3.2. 0 J hept-2-«it-2-earboxyl»ta -38- Example 15 (5K, SS) 3-12-1 (S J- (l-pyridiniua) J-l- (s) -cycloheyylUiloJ -£-(1- (*) -hydrexyathyl J-7-cxo-l-iiiMcyclo (3.2.0) hept-2-en»-2-eaxboxylata tad (SS, 6S) 3-12-( (R) - (l-fjyriiiniua) J-l- (R) -eydobeayl thiol -6-(1- (R) -hydroxytthyl]-7-cxo-l-i2*Mcyclo(3.2.0)heFt-2-ene-2-eirboxyl»t«. -39- « u Exanole 16 (5¾) a-1(2-pyrliii.niotthyl) thle)-165)-1 (IR) -hydroxyethyl)-7-oxo-l-mMcycIo (3.2.0) hcpt-2-tnt-2-c»rboxyl»tt •40-

Claims (6)

1. 8 2 · wherein R , R , A and R are as defined above; (3) reacting intermediate V in an inert organic solvent and in the presence of base with methanesulfonyl chloride or a functional acylating equivalent thereof to give an intermediate of the formula 15 20 N 0 S-A-0S02CH3 ' COOR VI vherein Ri, r8, A and are as defined above; (4) reacting intermediate VI in an inert organic 25 solvent with a source of iodide ion so as to displace the methanesulfonyloxy group with an iodo group and form an intermediate of the formula H -S-A-I N 1 2 1 —COOR X?’ are as defined II 30 9. A process for the preparation of a compound as claimed in claim 1 substantially as hereinbefore described with reference to any one of the Examples. 5 10. A compound as claimed in claim 1 whenever prepared by a process as claimed in claim 8 or claim 9. Dated this the 28th day of April, 1989. BY: (Signed) TOMKINS & CO., ApplicantsJ-Agents,

2. An intermediate as claimed in claim 1 5 R^ is hydrogen, CH^CH^-, t or ch3 An intermediate as claimed in claim 1 wherein 10 R is OH I CHjCH- An intermediate as claimed in claim 1 wherein R is OH CH 15

3. L· and the absolute configuration is 5R, 6S, 8R. 5. An intermediate as claimed in claim 1 1 8 R and R taken together represent wherein -44- 20

4. !> 4 V V Ο 6. An intermediate as claimed in any one of claims 1 to 5 wherein A is -CHCH2- or 7. An intermediate as claimed in any one of claims 1 to 6 wherein RSI is p-nitrobenzyl. 10 8. A process for the preparation of an inter mediate of the formula A— N-- 2' COOR 18 21 wherein R and R are as defined above and R is a con- 15 vnetional readily removable carboxyl protecting group in an inert organic solvent with diphenyl chlorophosphate in the presence of base to give an intermediate of the formula 20 J. 8 21 25 wherein R , R and F are as defined above; (2) reacting intermediate IV in an inert organic solvent and in the presence of base with a mercaptan reagent of the formula 30 HS-A-OH -46- 5 wherein A is as defined above to give an intenrediate of the formula

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