FI81355B - FOERFARANDE FOER FRAMSTAELLNING AV ANTIBAKTERIELLA 2-DIOXACYKLOALKYLTIOPENEMDERIVAT. - Google Patents

Description

1 81355

Process for the preparation of antibacterial 2-dioxacycloalkylthiopenem derivatives

The invention relates to a process for the preparation of antibacterial agents comprising a 2-azetidinone (betalactam) ring. Chemically prepared antibacterial agents in accordance with this invention include 2-substituted 6-α- (1-hydroxyethyl) -2-penem-3-carboxylic acid compounds.

Although certain 2-substituted 2-penem-3-carboxylic acid compounds have been reported in the past, there is a continuing need to find new compounds with the desired antibacterial therapeutic properties.

According to the present invention there are provided compounds of formula

OH

I 2 s

h3c jiUT

20 c> COOH

or a pharmaceutically acceptable salt thereof, wherein R is carbonyl or methylene; B is alkylene of 2 to 5 carbon atoms; alk is alkylene of 1 to 6 carbon atoms; and n is 0 or 1.

Preferred compounds of formula I are those wherein B is ethylene, A is methylene and n is 1, especially 2,81355 when R is 1,3-dioxacyclopent-4-ylmethyl or 1,3-dioxacyclopent-2-ylmethyl .

Also preferred are compounds of formula I wherein B is ethylene, A is carbonyl, n is 1 and alk is methylene, especially when R is 2-oxo-1,3-dioxacyclopent-4-ylmethyl.

Further preferred are compounds of formula I wherein B is propylene, A is methylene and n is 0, especially when R is 1,3-dioxacyclohex-5-yl.

Further preferred are compounds of formula I wherein B is propylene, A is carbonyl and n is 0, especially when R is 2-oxo-1,3-dioxacyclohex-5-yl.

The compounds of formula I may be used in a pharmaceutical composition comprising a compound of formula I and a pharmaceutically acceptable diluent or carrier for the treatment of a bacterial infection in a mammal.

The compounds of formula I are useful as antibacterial agents and contain a bicyclic ring of formula 6 | - 111 7 ^ L_N_Jb 25 0 4

Throughout this specification, a ring of formula III is referred to as 2-penem and the ring atoms are numbered as shown in formula III above. The carbon atom attached to ring atom 6 is given the number 8. Throughout this specification, the abbreviation PNB is also used for the p-nitrobenzyl group.

Carbon 5 has an absolute stereochemistry which is denoted by R using Prelog-Ingold's R, S-stereochemistry.

II

3,81355 list of notation used in this patent application. Thus, for example, a compound of formula I wherein R is 1,3-dioxacyclohex-5-yl is designated (5R, 6S) -6 - [(R) -1-hydroxyethyl] -2- (1,3-dioxacyclohexyl). 5-yl) thio-5-3-carboxyl-2-penem.

The compounds of formula I or pharmaceutically acceptable salts thereof are prepared according to the invention in such a way that a compound of formula

OH

10 jf H

HlllllC /. - S S-R

/ V-γ y H, C Jr || Wherein R 3 is as defined above and R 3 is a benzyl or p-nitrobenzyl group, the R 3 group is removed by hydrogenation and, if desired, the resulting compound of formula I is converted into a pharmaceutically acceptable salt.

The compounds of formula I can be synthesized according to Schemes A-C, which also show the preparation of the starting materials for the process according to the invention.

As shown in Scheme A, a compound of formula I can be prepared according to Yoshida et al.

Chem. Pharm. Bull., 29 (1981) pp. 2899-2909, a known dibromopenam of formula IV. In dibromopenam (IV), an exchange reaction with t-butylmagnesium chloride takes place at a temperature between about -30 ° C and -40 ° C, preferably at about -78 ° C, in a reaction-inert solvent such as tetrahydrorane, diethyl ether or toluene, preferably tetrahydrofuran. oven. Other organometallic reagents can also be used. The resulting reaction mixture is treated in situ with the appropriate aldehyde, i. acetaldehyde to give a 1-hydroxyethyl derivative 4 81,355. The aldehyde is added at about -80 to -60 ° C; for acetaldehyde about -78 ° C is preferred.

The resulting bromohydroxypenam V is hydrogenated to remove the 6-bromo substituent. A suitable hydrogenation catalyst is a noble metal catalyst such as palladium. The reaction is carried out in a protic solvent such as 1: 1 methanol-water or 1: 1 tetrahydrofuran-water, preferably 1: 1 methanol-water, at a pressure of about 1-4 atm, preferably 4 atm. and at a temperature of about 0 to 30 ° C, preferably 10 at about 25 ° C.

The resulting alcohol of formula VI can be protected with a trialkyl halosilane of formula i9

15 R9-Si-Q

Wherein R 1 is each alkyl of 1 to 6 carbon atoms and Q 20 is chlorine, bromine or iodine. Thus, dimethyl t-butylchlorosilane in the presence of an amine proton acceptor such as imidazole in a polar, aprotic solvent such as N, N-dimethylformamide at about 5-40 ° C, preferably at about 25 ° C, forms a tri-alkylsilyl protecting group for the hydroxyl, as shown in formula VII.

Il 5 81 355

Scheme A

Br HO Br S

Br ~ l · —r ~ s ^ ^> <

5 ^ -N ^ N

0 ^ 0 ^ C ° 2CH3 V CO2CH3

IV

HO \ / 10 J '*' - ['"' x / y * \ f" co-ch ^ 15 VI 2 3

Rq \ / \ 9

R g SiO

20 4-S — rs \.

VII c ° 2ch3 25 R Rq ^ \ 9 ^

RQ-SiO „Rg-SiO

9 /, O Ac / I OAc 3Q Κ9 ^ // | - ^ χ ^ NH "o> —N \ /

IX VIII I

co2ch3 35 6 81 355

Scheme B

R9 s IX - ^ R9 "? I0 \, ^ S_C_SRI0 5 ^ R>" "r- ^ y 0 = * - nh

X

i 10 R9 Rg R9-SiO _ R9-SiO s R "rf5 / Rl ° <_ R ^" ,, - rs' "s'R: - ° <T N co2PNB o" 5 "N”

0 CC0oPNB

15 2

XII XI

\ /

20 R RQ

K9. 9 R Q-SiO? R9 "^ iCi R? J, I | -r-y 10 _ ^ 9J" | - | Ύ

\ C0, PNB ^ ^ N ^ CO2PNB

25 0 2

XIII XIV

\ / 30 H0 - - -tor

O CO ,, PNB

A.

35

II

XV

7 81355

Scheme C

* 9

RQ-SiO

^ * 9 S

5 IX l ||| j-1-S-C-SR

-OF

XVA

r9 \

10 Rq-SiO

v 'Kq R c i y

9 S Rq-SiO

Jlllj-1— S-C-SR / R s

^ 1 Cl ^ - 9 S

s? -NJ \\ n-1- S-C-SR

° CO-PNB ^ -N

15 ° ^ OH

co2pnb

XVII XVI

20

V? I0 S

R I 11

9 S-C-SR

J "rf

25 y ^ P (C6H5) 3 _ ^ XIV

co2pnb

XVIII

30 8 81355

Treatment of a compound of formula VII with mercuric acetate in acetic acid at about 90 ° C affords olefin VIII.

To obtain the desired azetidinone IX, the olefin VIII is ozonated in a reaction-inert solvent such as dichloromethane at a temperature between -80 ° C and -40 ° C, preferably at about -78 ° C. The reaction product is treated with an alkanol such as methanol to give azetidine IX.

As shown in Scheme B, a compound of formula IX is treated with a trithiocarbonate salt of formula M * R 10 -SC (S) -S ', wherein R 10 is alkyl of 1 to 4 carbon atoms, preferably ethyl, and M is a metal such as sodium or potassium, to give a compound of formula X. This conversion of compound IX to compound X is carried out in an organic solvent which is inert to the reaction, in water or a mixture thereof, preferably a mixture of water and dichloromethane, at a temperature in the range from about 0 to 35 ° C, preferably at about 25 ° C.

The compound of formula X is condensed with p-nitrobenzyl chlorooxalate using a tertiary alkylamine in which each alkyl contains, for example, 1 to 4 carbon atoms, such as ethyldiisopropylamine, to give a compound of formula XI. This condensation reaction is carried out in a reaction-inert solvent, preferably dichloromethane, at a temperature in the range of about 5 to 25 ° C, preferably about 10 ° C.

The resulting compound of formula XI is cyclized using a trialkyl phosphite in which the alkyls contain from 1 to 4 carbon atoms, such as triethyl phosphite, in a reaction-inert solvent such as trichloromethane at a temperature in the range of about 40 to 80 ° C, preferably about 60 ° C. To obtain a penem according to XII.

The thio group of XII is oxidized to the corresponding sulfoxide XIII with an oxidant such as m-chloroperbenzoic acid in a reaction inert solvent such as dichloromethane at a temperature in the range of about -10 to -30 ° C, preferably -20 ° C: in.

The sulfoxide XIII is substituted with a mercaptide of formula R-S 'using, for example, a sodium or potassium salt which is reacted with the sulfoxide XIII in a polar organic solvent such as ethanol or acetonitrile at a temperature in the range of about -50 to -10 ° C, preferably at about -35 ° C.

The mercaptans of the formula R-SH or the thioacetates of the formula R-S-C (O) CH3 used as starting materials are known for many of the meanings of R and those which are not known can be prepared by analogous methods known in the art. For an overview, see J.L. Warden, 15 "Preparation of Thiols" in The Chemistry of the Thiol Group, S. Patai, editor, John Wiley & Sons, London, 1974, Chapter 4. also Volante, Tetrahedron Letters, 22, 3119-3122 (1981) for the conversion of alcohols to thiols and thiol esters using triphenyl-20-phosphine and dialkyl azodicarboxylate in the presence of alcohol and suitable thiolic acid.

Compounds of formula XIV are deprotected with a trialkylsilyl group to give a compound of formula XV prior to hydrogenation to remove the acid protecting group (PNB). The trialkylsilyl group is removed with tetraalkylanunonium fluoride in an ethereal solvent such as tetrahydrofuran at a temperature in the range of about 15-40 ° C, preferably at about 25 ° C.

Conversion of a compound of formula XV to a compound of formula I 30 The process of the invention is carried out using a conventional hydrogenation reaction and is carried out in this type of conversion in a conventional manner. Thus, a solution of a compound of formula XV is stirred or shaken under an atmosphere of hydrogen or hydrogen is stirred in an inert diluent such as nitrogen or argon in the presence of a noble metal hydrogenation catalyst such as palladium / calcium carbonate or palladium / Celite catalyst. Suitable solvents for this hydrogenation include lower alkanols such as methanol, ethers such as tetrahydrofuran and dioxane, low molecular weight esters such as ethyl acetate and butyl acetate, water, and mixtures of these solvents. However, it is common to choose conditions in which the starting material is soluble, such as aqueous ethers, for example, aqueous tetrahydrofuran, at a pH of about 7-8. The hydrogenation is usually carried out at room temperature and at a pressure of about 0.5-5 kg / cm 2. The catalyst is usually present in amounts of about 10% by weight of the starting material in an amount equal to the amount of the starting material, although higher amounts may be used. The reaction generally takes about 1 hour, after which the compound of formula I is recovered simply by filtration and removal of the solvent in vacuo. If palladium / calcium carbonate is used as the catalyst, the product is isolated as the calcium salt, and if a palladium / Celite catalyst is used, the product is isolated as the sodium salt.

The compound of formula I can be purified by methods conventionally used for β-lactam compounds. The compound of formula I can be purified, for example, by further filtration of gee-25 on Sephadex or recrystallization.

An alternative synthetic method is shown in Scheme C. The azetidine of formula IX is reacted with a trithiocarbonate of formula M + R-S-C (S) -S ", wherein M is a metal such as sodium or potassium, using the procedure described above to prepare compound X.

The resulting trithiocarbonate XVA is treated with (p-nitrobenzyloxycarbonyl) (dihydroxy) methane in an aprotic solvent such as benzene, toluene 35 or dimethylformamide, preferably benzene, at a temperature in the range of about 25 to 110 ° C, preferably about 80 ° In C to give an alcohol of formula XVI.

The corresponding chloride XVII is prepared from alcohol XVI by treatment with thionyl chloride in a reaction-inert organic solvent such as dichloromethane in the presence of a blocked amine acting as an acid acceptor such as 2,6-lutidine at a temperature in the range of about -10 to 75 ° C, preferably 0 ° C. .

Chloride XVII is reacted with a triarylphosphine, such as triphenylphosphine, in a reaction-inert solvent, such as tetrahydrofuran, in the presence of a tertiary amine, such as 2,6-lutidine, at a temperature of about 25 ° C to give a compound of formula XVIII which is cyclized by heating. at reflux in an aromatic solvent such as toluene to give a penem of formula XIV.

Trithiocarbonate salts of the formula M + R-S- (C = S) -S "are prepared from the appropriate mercaptan of the formula R-SH or by treating the thioacetate of the formula RSC (O) CH3 with an alkali metal alkoxide followed by carbon disulphide.

When the above-mentioned Yoshida et al. method, the stereochemistry of penen on carbon 6 as well as the hydroxyethyl group attached to carbon 6 in formula I is as shown in formula I. The release stereochemistry for the cyclization product using the methods of Schemes B or C is stereochemistry in which the hydrogen at position 5 of the penem ring is in the trans position with respect to the hydrogen attached to carbon 6 and in the α-configuration. Alternatively, stereochemistry may be described as 5R, 6S, 6- (R) -1-hydroxyethyl.

The compounds of formula I are acidic and form salts with basic substances. The preparation of such salts is considered to be within the scope of this invention. These salts can be prepared by standard methods, such as by contacting the acidic and basic components, usually in a stoichiometric ratio, with each other in water or in an anhydrous or partially aqueous medium, as appropriate. They are then recovered by filtration, mixing as a non-solvent, followed by filtration, evaporation of the solvent or, in the case of aqueous solutions, lyophilization, as appropriate. The basic substances suitably used for salt formation are of both organic and inorganic type and include ammonia, organic amines, alkali metal hydroxides, carbonates, bicarbonates, hydrides and alkoxides, as well as alkaline earth metal hydroxides, carbonates, hydrides and alkoxides. Representative examples of such bases include primary amines such as n-propylamine, n-butyl-amine, aniline, cyclohexylamine, benzylamine, and octylamine; secondary amines such as diethylamine, morpholine, pyrrolidine and piperidine; tertiary amines such as triethylamine, N-ethylpiperidine, N-methylmorpholine and 1,5-diazebicyclo [4.3.0] non-5-ene; Hydroxides such as sodium hydroxide, potassium hydroxide, ammonium hydroxide and barium hydroxide; alkoxides such as sodium methoxide and potassium methoxide; hydrides such as calcium hydride and sodium hydride; carbonates such as potassium carbonate and sodium carbonate; bicarbonates such as sodium bicarbonate and potassium carbonate; and alkali metal salts of long chain fatty acids such as sodium 2-ethylhexanoate.

Preferred salts of the compounds of formula I are the sodium, potassium and calcium salts.

Pharmaceutically acceptable salts of the compounds of formula I include salts which are free from significant adverse side effects at the usual levels of use; such are, for example, their sodium, potassium or calcium salts.

35 Compounds of formula I and their salts

II

The in vitro activity of i3 81 355 can be demonstrated by measuring their minimum inhibitory concentrations (MICs) in pg / ml against various microorganisms. The method followed is the method recommended by the International Collabrorative 5 Study On Antibiotic Sensitivity Testing (Ericcson and

Sherris, Acta. Pathologica et Microbiologia Scandinav., Supplement 217, Part B: 64-68 [1971]) and uses brain-cardiac infusion (BHI) agar as a transplant replication medium. After one night, the growth tubes are diluted 100-10-fold for use as a standard inoculum (20,000-10,000 cells in about 0.002 ml are placed on an agar surface; 20 ml BHI agar / plate). Twelve-fold dilutions of test compounds are used at an initial concentration of 200 pg / ml of test substance. Simple colonies are disregarded when the plates are counted after 18 hours at 37 ° C. The susceptibility (MIC) of the organism used is the lowest concentration of compound that can provide complete inhibition of growth as judged to the naked eye.

81355

EXPERIMENTAL RESULTS

In vitro antibacterial activity Minimum inhibitory concentration (MIC) MIC (μg / ml) · · R = CH-J | Jj R = -f)

Micro-organism 2 / \ '_ (known) _ "__

Staph, aureus 005 0.10 0.05 052 0.10 0.05 110 0.10 0.05 400 0.10 0.05

Staph, epi. 087 0.30 0.20 111 0.10 0.05 126 0.78 1.56

Strep, faec. 006 3.12 3.12

Strep, pyog. 054 ί = 0.025 · 6τ0.025 203 ^ 0.025 4 = 0.025

Strep, pneum. 012 - i =. 0.025 E. coll 125 6.25 0.20 129 25 1.56 256 6.25 0.20 470 0.39 - = ^ 0.025

Ps. Aerug. 104> 50> 50 663> 50> 50

Kleb. pn. 009 6.25 0.20 031 6.25 0.20

Kleb. Oxy. 024 6.25 0.39

Past. mult. 001 0.10 0.05

Serr. November. 017 25 0.78

Neiss. sic. 000 0.05 - 0.025

Ent. aerog. 040 3.12 0.10

Ent. cloac. 009 25 1.56

Prov. stua. 013 50 25

Prov. ret. 025 12.5 1.56. . Morg. Morg. 001 6.25 3, 12

II

is 81355

The compounds of formula I and their pharmaceutically acceptable salts are suitable for controlling bacterial infections in mammals, including humans, e.g. infections caused by susceptible strains of Staphylococcus aureus.

The compounds of this invention may be administered orally or parenterally, i.e., intramuscularly, subcutaneously, intraperitoneally, or intravenously, alone or in combination with a pharmaceutically acceptable carrier.

The ratio of active ingredient to carrier depends on the chemical nature, solubility and stability of the active ingredient, as well as the intended dose. The ratio of pharmaceutically acceptable carrier to penem compound is normally in the range of 1:10 to 4: 1. For oral administration, these compounds can be used in the form of tablets, capsules, lozenges, lozenges, powders, syrups, elixirs, aqueous solutions and suspensions, and the like. Useful carriers for tablets include lactose, sodium citrate and salts of phosphoric acid. Various disintegrants such as starch and lubricants such as magnesium stearate, sodium lauryl sulfate and talc are commonly used in tablets. Useful diluents for capsules include lactose and large molecular weight polyethylene glycols. When aqueous suspensions for oral use are desired, the active ingredient is combined with emulsifying and suspending agents. Sweetening and / or flavoring agents may be added. For parenteral administration, sterile solutions of the active ingredient are usually prepared and the pH of the solutions adjusted and buffered. For intravenous use, the total solute content should be adjusted to make the preparation isotonic.

The treating physician will prescribe the appropriate dose of so-called 81355 for a particular human subject, and this can be expected to vary with the age, weight and response of the patient, as well as the nature and severity of the patient's symptoms. The compounds of formula I are normally administered orally in doses ranging from about 10 to about 200 mg / kg of body weight per day and parenterally in doses of from about 10 to about 400 mg / kg of body weight per day. In some cases, it may be necessary to use doses outside these limits.

The following examples and preparations are set forth for further illustration only. Infrared (IR) spectra were measured as either potassium bromide wafers (KBr-Kokko), Nujol gauze, or as solutions in chloroform (CHCl 3), methylene chloride (CH 2 Cl 2), or dimethyl sulfoxide (DMSO), and diagnostic absorption bands are reported as either 15 μm or -1). Nuclear magnetic: resonance (NMR) spectra were measured for solutions in deuterochloroform (CDCl 3), perdeuterated water (D 2 O) or per-deuterodimethyl sulfoxide (DMSO-d 6) or mixtures thereof, and the positions of the peaks are expressed in parts per million in alc.vir-20 in tetramethyl. The following abbreviations are used for peak shapes: s simple; d double; t triple; q quadruple; m multiple; b wide; w weak; c complex. The abbreviations "ss" and "sss" mean that the proton in question appeared as two or three simple peaks, respectively, due to the presence of diastereoisomers In all examples and preparations, the abbreviation "PNB" means p-nitrobenzyl.

Example 1 Sodium (5R, 6S) -6 - [(R) -1-hydroxyethyl] -2- (1,3-dioxacyclohex-5-yl) thio-2-penem-3-carboxylate.

The pH of a suspension of 41 mg of 10% palladium in diatomaceous earth in 8 ml of distilled water and 8 ml of tetrahydrofuran was adjusted to about 7.5 with 0.02 M aqueous sodium bicarbonate solution. A solution of 41 mg of p-nitrobenzyl- (5R, 6S) -6 - [(R) -1-hydroxyethyl] -2- (1,3-dioxacyclohex-5-yl) thio-2-penem was added. -3-carboxylate in 4 mL of tetrahydrofuran and 4 mL of distilled water, and the resulting mixture was hydrogenated at 3.79 x 10 5 Pa (55 psi) for 75 minutes. An additional 40 mg of 10% palladium on diatomaceous earth was added to the reaction mixture and the pH of the suspension was adjusted to about 7.0 with 0.02 M aqueous sodium bicarbonate solution. The mixture was hydrogenated under 3.79 χ 105 Pa (55 psi) hydrogen for 75 min, then the catalyst was removed by filtration and the filtrate was concentrated in vacuo to remove tetrahydrofuran. The pH of the resulting aqueous solution was adjusted to 7.0, and the solution was extracted with two 20 ml portions of ethyl acetate. The aqueous phase was then lyophilized to give 30 mg (96% yield) of the title compound as an amorphous solid. The infrared spectrum of the title compound had an absorption at 5.67 μm as a Nujol gauze.

The procedures were repeated to give the title compound in 85% yield. The spectral values are as follows: 20 NMR (D 2 O, 250MH 2): 1.29 [3H, d, J = 6.5 Hz]; 3.57 [1 H, m]; 3.90 [2H, m]; 3.92 [1H, dd, J = 6.0, 1.4 Hz]; 4.24 [1H, qd, J = 6.5, 6.0 Hz]; 4.29 (2H, m]; 4.86 & 4.94 [2H, each d, JAB = 6.5 Hz]; and 5.68 [1H, d, J = 1.4 Hz] ppm. KBr disk): 3040 (b), 2966 (b), 2846 (w), 1770 (s), 1593, 1378, 1295, 1169, 1136, 1053, 1020 and 924 cm-1.

UV (H 2 O) (extinction coefficient in parentheses): 254 (4470) and 320 (5240) nm. [α] D (H 2 O): + 139.0 °.

Example 2

Following the procedure of Example 1, compounds of formula XV were followed to give the corresponding compounds of formula I as sodium salts having the substituent R and the infrared spectral values shown in Table 1; medium in parentheses.

35 is 81355

Table 1 _R_IR (pm) - Yield (%) 1,3-dioxacyclopent-5,7 (Nujol gauze) 80 4-ylmethyl 5 1,3-dioxacyclopent-2.93, 5.65 and 6.26 82 2-ylmethyl (KBr disc) 2-Oxo-1,3-dioxacyclo-2.94, 5.66 and 6.28 71 pent-4-ylmethyl (KBr disc)

10 Preparation A

p-nitrobenzyl (5R, 6S) -6 - [(R) -1-hydroxyethyl] -2- (1,3-dioxacyclohex-5-yl) thio-2-penem-3-carboxylate

To a solution of 70 mg (0.12 mmol) of p-nitrotent-15-silyl- (5R, 6S) -6 - [(R) -1-butyldimethylsilyloxyethyl] -2- (1,3-dioxacyclohex-5-yl ) thio-2-penem-3-carboxylate in 4 ml of anhydrous tetrahydrofuran, 0.07 ml (1.2 mmol) of acetic acid and 0.36 ml (0.36 mmol) of tetrabutylammonium fluoride in 1N Luo in tetrahydrofuran were added. After stirring for 40 hours at room temperature under a nitrogen atmosphere, 40 ml of ethyl acetate were added and the resulting solution was washed with 25 ml of saturated aqueous sodium bicarbonate solution, 25 ml of water and 25 ml of saturated aqueous sodium chloride solution. The ethyl acetate solution was then dried over anhydrous sodium sulfate and evaporated in vacuo. The crude product (70 mg) was chromatographed on silica gel (35 g) eluting with 2: 1 chloroform-ethyl acetate to give 46 mg (82% yield) of the title product.

The infrared spectrum of the dichloromethane solution of the title product had absorbances at 5.58, 5.91 and 6.58. The 250 MHz NMR spectrum of the perdeuterodimethylsulfoxide solution of the title compound had peaks at 1.17 (d, 3H); 3.54 (m, 1 H); 3.76-3.95 (c, 3 H), 4.02 (m, 1 H); 4.2 (m. 35H); 4.82 (q, 2 H), 5.25 (d, 1 H), 5.38 (q, 2 H); 5.78 (d, 1 H), 7.7 (d, 2 H); and 8.25 (d, 2H) ppm.

Il i9 81 355

The procedure was repeated to give the title compound in 94% yield, m.p. 214-215 ° C (from tetrahydrofuran). The spectral values are as follows: NMR (DMSO-d 6, 250 MHX): 1.17 [3H, d, J = 6 Hz]; 3.53 [1H, 5 m]; 3.82 [2H, m]; 3.90 [1H, dd, J = 6.1 Hz]; 4.01 [1H, m]; 4.20 [2H, m]; 4.79 & 4.83 [2H, each d, JAB = 6 Hz]; 5.26 [1H, d, J Hz]; 5.31 & 5.45 [2H, each d, JAB = 14 Hz]; 5.78 [1H, d, J = 1 Hz]; 7.69 [2H, d, J = 9 Hz]; and 8.24 [2H, d, J = 9 Hz] ppm. IR (KBr disc): 3452, 2965, 10 2851 (w), 1776 (S), 1693 (S), 1609 (w), 1520, 1502, 1376, 1220, 1194, 1176, 1135, 1119, 1047 and 1023 cm-1.

Preparation B

The procedures of Preparation A were followed using compounds of formula XIV to give the corresponding compounds of formula XV; their substituent R, yield and spectral values (solvent in parentheses) are shown in Table 2.

20 81 355

Table 2 _R_IR (pm) - NMR (ppm) - Yield (%) 1,3-dioxa-5.59, 5.92 1.24 (d, 3H); 69 cyclopent and 6.58 3.03-3.27 δ 4-ylmethyl (CH 2 Cl 2) (m, 2H); 3.48-4.4 (c, 6H); 4.83 (s, 1H); 5.0 (s, 1 H); 5.3 (q, 10H); 5.6 (d, 1 H); 7.55 (d. 2H); and 8.12 (d, 2H) (CDCl 3) 1,3-dioxa-5.58, 5.92 1.26 (d, 3H); Cyclopent-2 and 6.57 3.18 (d, 2H); ylmethyl (CH 2 Cl 2) 5.64-4.5 (c, 6H), 5.0 (t, 1H), 5.3 (g, 2H); 5.6 (d, 1 H); 7.6 (d. 2H); and 8.2 (d, 2H) (CDCl 3) 2 -oxo-1,3,5,5,5,9,26,26 (d, 3H); 52 Dioxacyclo and 6.58 2.96 (d, 2H); pent-4-yl (CH 2 Cl 2) 3.7 (m, 1H); methyl 4.0-5.0 (c, 4H); 5.3 (q. 2H); 5.62 (d, 1 H), 7.58 (d, 2 H); and 8.18 (d, 2H) (CDCl 3)

35 Preparation C

p-Nitrobenzyl (5R, 6S) -6 - [(R) -1-t-butyldimethylsilyloxyethyl] -2- (1,3-dioxacyclohex-5-yl) thio-2-penem-3-carboxylate

Sodium methoxide (27 mg, 0.5 mmol) was added to a solution of 1,3-dioxacyclohex-5-ylthioacetate (81 mg, 0.5 mmol) in 5 mL of anhydrous ethanol cooled to -35 “To C in a nitrogen atmosphere. After 45 minutes at -35 ° C, a solution of 300 mg (ca. 0.5 mmol) of crude p-nitrobenzyl-45 (5R, 6S) -6 - [(R) -1-butyldimethylsilyloxyethyl] -2 - 2i 81355 ethylsulfinyl-2-penem-3-carboxylate in 5 ml of tetrahydrofuran cooled to -50 ° C. The resulting solution was stirred at -35 ° C for 60 min, then 0.029 mL (0.5 mmol) of acetic acid was added and the solution was evaporated in vacuo. The residue was dissolved in 50 ml of ethyl acetate, and the resulting solution was washed successively with 25 ml of saturated aqueous sodium bicarbonate solution, 25 ml of water, and 25 ml of saturated aqueous sodium chloride solution. The ethyl acetate layer was dried over anhydrous sodium sulfate and evaporated in vacuo. The crude product (360 mg) was chromatographed on silica gel (100 g) eluting with chloroform to give 70 mg (24% yield) of the title product as a viscous gum.

The title compound in dichloromethane solution had absorbances at 5.59, 5.9 and 6.57 in the infrared spectrum. The NMR spectrum of the deuterochloroform solution of the title compound had peaks at 0.03 (s, 3H); 0.06 (s. 3H); 0.8 (s, 9H), 1.25 (d, 3H), 3.4-3.86 (c, 4H), 4.0-4.5 (c, 3H); 4.63 (d, 1 H); 4.95 (d, 1 H), 5.27 (q, 2 H): 5.63 (d, 1 H); 7.56 (d. 2H); and 8.18 (d, 2H) ppm.

The procedure was repeated to give the title compound in 65% yield, m.p. 133-134 ° C. (Diethyl ether / pet ether are). The spectral values are as follows: NMR (CDCl 3, 250 MH 2): 0.04 [3H, s]; 0.07 [3 H, s]; 0.83 [9H, 25 s]; 1.26 [3H, d, J = 6.3 Hz]; 3.5-3.75 [3H, m], 3.75 (1H, dd, J = 4.0 1.5 Hz]; 4.2-4.4 [3H, m]; 4.67 & 4 , 97 [2H, d, JAB = 6.2 Hz], 5.21 & 5.42 (2H, d, JAB = 13.7 Hz), 5.67 [1H, d, J = 1.5 Hz], 7.61 [2H, d, J = 8.7 Hz], and 8.21 [2H, d, J = 8.7 Hz] ppm IR (KBr disc): 30 2946, 2927, 2850 , 1797 (s), 1697 (s), 1610, 1512, 1374, 1345, 1320, 1230, 1189, 1168, 1122, 1064, 1025, 982, 931, 835, 801 and 772 cm-1.

Preparation D

The procedures of Preparation C were followed to give the corresponding compound of formula XIV 22 81 355 to give the corresponding thioacetate; the substituent R, yield and spectral values (solvent in parentheses) of the obtained compounds are shown in Table 3.

Table 3 R_IR (pm) -NMR (ppm) -Yield (%) 1,3-dioxa-5.6, 5.92 0.03 (s, 3H); 37 cyclopent-4 and 6.57 0.06 (s, 3H); Ylmethyl (CHCl 2) 0.83 (s, 9H); 1.23 (d. 3H); 2.97-3. 22 (m, 2H); 3.5-4.4 (c. 5H); 4.83 (s, 1 H); 5.02 (s, 1 H); 5.26 (q, 2 H); 5.6 (d, 1 H); 7.54 (d. 2H); 20 and 8.13 (d, 2H) (CDCl 3) 1,3-dioxa-5.58, 5.9 0.03 (s, 3H); 41 cyclopent and 6.57 0.06 (s, 3H), 2-ylmethyl (CH 2 Cl 2) 0.82 (s, 9H), 25 style 1.24 (d, 3H); 3.17 (d. 2H); 3.63-4.5 (C, 5H); 5.02 (t, 1 H); 5.3 (q, 2 H); 5.62 (d, 1 H); 7.58 (d. 2H); and 8.18 (d, 2H) (CDCl 3) δ 2-oxo-1,3,5,5,8, 5,9 0,02 (s, 3H); 27 dioxacyclo and 6.57 0.06 (s, 3H); pent-4-yl- (CH 2 Cl 2) 0.82 (s, 9H); methyl 1.23 (d, 3H); 2.92 (d. 2H); 40 3.7 (m. 1H); 4.0-5.0 (c. 4H); 5.25 (q. 2H); 5.6 (d, 1 H); 7.53 (d. 2H); and 8.14 (d. 2H); (CDCl3)

II

23 8 1 3 5 5

Preparation E

p-Nitrobenzyl (5R, 6S) -6 - [(R) -1-butyldimethyloxyethyl] -2-ethylsulfinyl-2-penem-3-carboxylate 5 A solution of 970 mg (4.78 mmol, purity 85%) m-chloroperbenzoic acid in 25 ml of methylene chloride was added to a solution of 2.5 g (4.78 mmol) of p-nitrobenzyl- (5R, 6S) -6 - [(R) -1-t -butyldimethylsilyloxyethyl] -2-ethylthio-2-penem-3-carboxylate 125 in 10 ml of methylene chloride and cooled to -20 ° C under a nitrogen atmosphere. The mixture was stirred at -20 ° C for 3 h, then washed successively with two 70 ml portions of saturated aqueous sodium carbonate solution, 70 ml of water and 70 ml of saturated aqueous sodium chloride solution. The methylene chloride solution was dried over anhydrous sodium sulfate and evaporated in vacuo to give the title compound (2.2 g, 86% yield) as a yellow foam.

The infrared spectrum of the title compound (as a dichloromethane solution) had absorbances at 5.54, 5.86 and 6.53. The NMR spectrum of the title compound (as deuterochloroform solution) had peaks at 0.06, 0.08, 0.1 and 0.12 (4s, total 6H); 0.8 (s, 9 H), 1.12-1.58 (m, 6 H); 3.1 (m. 2H); 3.86 (m, 1 H), 4.3 (m, 1 H), 5.3 (m, 2 H); 5.67 and 5.78 (2d, total 1H), 7.54 (d, 2H), and 8.18 (d, 2H) ppm.

25 Preparation F

p-Nitrobenzyl (5R, 6S) -6 - [(R) -1-butyldimethylsilyloxyethyl] -2-ethylthio-2-penem-3-carboxylate p-nitrobenzyloxalyl chloride (5.85 g, 0.024 mol) was added to a mixture of 7.3 g (0.02 moles) of (3-at-butyldimethylsilyloxyethyl-4-ethylthio (thiocarbonyl) thio-2-oxoazetidine and 4.8 g (0.048 moles) of calcium carbonate in 70 ml): A solution of 4.17 ml (0.024 moles) of diisopropylethylamine in 20 24 81355 ml of methylene chloride was added dropwise at such a rate that the temperature was maintained at 12 ° C. in methylene chloride and cooled to 10 ° C under a nitrogen atmosphere. The mixture was stirred for 60 minutes at 10 ° C, then washed with two 50 ml portions of ice-cold water, dried over anhydrous sodium sulphate and evaporated in vacuo to a viscous oil, the resulting crude p-nitrobenzyl- (3-at-butyldimethylsilyloxyethyl). -oxo-azetidinyl) -oxoacetate was dissolved in 300 ml of ethanol-free chloroform and the resulting solution were heated under reflux under a nitrogen atmosphere while a solution of 6.85 ml (0.04 mol) of triethyl phosphite in 50 ml of ethanol-free chloroform was added dropwise over 2 hours. The resulting solution was heated at reflux for 16 h and then evaporated in vacuo. The residue was chromatographed on silica gel (800 g) eluting with 95: 5 toluene-ethyl acetate to give 5.5 g (53% yield) of the title compound as a yellow foam.

The infrared spectrum of the title compound (as a dichloromethane solution) had absorbances at 5.56, 5.89 and 6.54 at 20. The NMR spectrum of the title compound (as deuterochloroform solution) had peaks at 0.07 (s, 3H), 0.1 (s, 3H), 0.85 (s, 9H); 1.12 - 1.53 (m, 6H); 2.97 (q, 2 H); 3.7 (m 1H); 4.25 (m, 1 H); 5.3 (q. 2H); 5.63 (d, 1 H); 7.38 (d. 2H); and 8.18 (d, 2H) ppm.

The 4-ethylthio (thiocarbonyl) thioacetidinone (as deuterochloroform) NMR spectrum had peaks at 0.06 (s, 6H), 0.8 (s, 9H); 1.14 - 1.62 (m; 6H); 3.14 - 3.63 (m, 3H); 4.33 (m, 1 H); 5.16 (s, 2 H), 6.7 (d, 1 H); 7.5 (d. 2H); and 8.17 (d, 2H) ppm.

30 Preparation G

3-a-t-butyylldlmetyylisilyylioksietyyli-ethyl-4-thio (thiocarbonyl) thio-2-oxo-atsetldiini

Ethanethiol (8.5 mL, 0.115 mol) was added to a solution of 4.18 g (0.104 mol) of sodium hydroxide in 250 mL of water cooled to 0-5 ° C under a nitrogen atmosphere. After 15 minutes, 7.73 ml (0.12 mol) of carbon disulphide was added and the mixture was stirred at 0-5 ° C for 35 minutes. A solution of 15.0 g (0.0522 mol) of 4-acetoxy-3-t-butyldimethylsilyloxyethyl-5-azetidinone in 500 ml of methylene chloride was added and the mixture was stirred vigorously at room temperature for 24 h. The aqueous phase was separated and extracted with two portions. 150 ml portion of methylene chloride. The combined methylene chloride fractions were washed with two 200 ml portions of water 10 and 200 ml of saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate and evaporated in vacuo. The obtained crude title product (18 g) was chromatographed on silica gel (500 g) eluting with 99: 1 chloroform-ethyl acetate to give 9.1 g (48% yield) of the title trithiocarbonate as a yellow foam.

The infrared spectrum of the title compound (as a dichloromethane solution) had absorbances at 5.62 and 9.2. The NMR spectrum of the deuterochloroform solution of the title compound had peaks at 0.08 (s, 6H), 0.8 (s, 9H); 1.02-1.5 (m. 6H); 3.0-3.48 (m. 3H); 4.12 (m, 1 H); 5.54 (d, 1 H); and 6.57 (b, 1H) ppm.

Preparation H

1,3-Dioxacyclohex-5-yl p-toluenesulfonate 25 p-Toluenesulfonyl chloride (38.1 g, 0.2 moles) was added to a solution of 20.8 g (0.2 moles) of glycerol formal [the mixture contained 67 % 1,3-dioxan-5-ol and 33% (1,3-dioxolan-4-yl) methanol] in 200 ml of pyridine and cooled to 0 ° C under a nitrogen atmosphere. The reaction mixture was stirred at 0 ° C for 1/2 h, then at 25 ° C for 20 h. The mixture was added to 500 ml of 6N aqueous hydrochloric acid solution, and the resulting mixture was extracted with four 200 ml portions of ethyl acetate. The combined ethyl acetate extracts were washed with two 200 ml portions of 1N aqueous chloro-35 hydrochloric acid, two 200 ml portions of water 26 81 355 and 200 ml of saturated aqueous sodium chloride, dried over anhydrous sodium sulfate and evaporated in vacuo to an oil. The crude product was dissolved in 500 ml of diisopropyl ether, after which the desired 1,3-dioxo-5-acyclohex-5-yl tosylate crystallized. Filtration gave 17.4 g of a white crystalline tosylate, m.p. 91-92 ° C. An additional 4.3 g of crystalline tosylate was obtained from the mother liquors (total yield 42%). The NMR spectrum of the title compound (as deuterochloroform) had peaks at 2.45 (s, 10 3H); 3.54-4.13 (c, 4 H); 4.26-4.6 (m, 1 H), 4.75 (s, 2 H); 7.3 (d. 2H); and 7.8 (d, 2H) ppm.

Preparation I

1,3-Dioxacyclopent-4-ylmethyl p-toluenesulfonate 15 p-Toluenesulfonyl chloride (76.2 g, 0.4 mol) was added to a solution of 104.1 g (1 mol) of glycerol formal [the mixture contained 67% 1, 3-dioxacyclohex-5-ol and 33% (1,3-dioxacyclopent-4-yl) methanol] in 1000 ml of pyridine and cooled to 0 ° C under a nitrogen atmosphere. The reaction mixture was allowed to stand for 20 hours at 0 ° C, then allowed to warm to room temperature and added to 1500 ml of 6N aqueous hydrochloric acid solution. The resulting mixture was extracted with four 500 mL portions of ethyl acetate. The combined ethyl acetate-25 extracts were washed with two 500 ml portions of 6N aqueous hydrochloric acid, two 500 ml portions of water and 500 ml of saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate and evaporated in vacuo. The oily product (78.4 g) consisted of a ca. 2: 1 mixture of 1,3-dioxacyc-30-lopent-4-ylmethyl tosylate and 1,3-dioxacyclohex-5-yl tosylate, which was used without purification in the next step (Preparation K).

Preparation J

1,3-Dioxacyclohex-5-ylthioacetate 35 A solution of 28.0 g (0.108 mol) of 1,3-dioxo 27 81 355 acacyclohex-5-yl p-tosylate and 24.6 g (0.216 mol) of potassium thioacetate 500 in dimethylformamide, heated at 80 ° C under nitrogen for 20 h. The reaction mixture was then cooled to room temperature and diluted with 1000 mL of water. The resulting mixture was extracted with six 300 mL portions of ethyl acetate. The combined ethyl acetate extracts were washed with four 500 ml portions of water and 500 ml of saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate and evaporated in vacuo to an oil. The product was distilled to give 6.25 g (36% yield) of the title thioacetate, b.p. 70 ° C (0.4 mm).

The NMR spectrum of the title compound (as deuterochloroform solution) peaked at 2.34 (s, 3H); 3.4-4.36 (c, 5H); and 4.8 (q, 2H) ppm.

The procedure was repeated to give the title compound in 49% yield, b.p. 85-89 ° C (0.7 mm).

NMR (CDCl 3, 250 MH 2): 2.34 (3H, s); 3.7-3.85 (3 H, m); 4.05-4.2 (2 H; m); 4.79 (1H, d, Jgem = 6.2 Hz); and 4.89 (1H, d, 20 μg = 6.2 Hz) ppm.

Preparation K

(1,3-dioxa-4-yl) methylthioacetate

A mixture of 78 g (0.3 mol) of 1,3-dioxacyclopent-4-yl tosylate (from Preparation I) and 27.4 g (0.24 mol) of potassium thioacetate in 1500 ml of acetone was heated under reflux under nitrogen overnight. The reaction mixture was then evaporated in vacuo and the residue was dissolved in 500 ml of ethyl acetate and 500 ml of water. The aqueous layer was extracted with 500 ml of ethyl acetate. The combined ethyl acetate extracts were washed with two 500 ml portions of water and 500 ml of saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate and evaporated in vacuo. The residue, which consisted of a solid suspended in oil, was filtered. The filtrate was distilled under reduced pressure to give 28 81 355 20.8 g (54%) of 1,3-dioxacyclopent-4-ylmethyl tosylate, b.p. 65-70 ° C (0.2 mm).

The solid product was washed with ether to give 18.4 g of 1,3-dioxacyclohex-5-yl tosylate.

The NMR spectrum of the title compound (as deuterochloroform solution) peaked at 2.37 (s, 3H); 3.1 (d. 2H); 3.4-4.4 (c. 3H); 4.86 (s, H); and 5.02 (s, 1H) ppm.

Preparation L

(1,3-Dioxacyclopent-2-yl) methylthioacetate 10 A mixture of 5.0 g (0.03 moles) of 2-bromomethyl-1,3-dioxacyclopentane and 5.13 g (0.045 moles) of potassium thioacetate In 60 mL of acetone, heated to reflux under nitrogen overnight. The mixture was filtered and the filtrate was evaporated in vacuo. The residue was partitioned between 100 ml of ethyl acetate and 60 ml of water. The aqueous layer was extracted with 50 ml of ethyl acetate, and the combined portions of ethyl acetate were washed with 50 ml of water and 50 ml of saturated aqueous sodium chloride solution. The ethyl acetate solution was dried over anhydrous sodium sulfate and evaporated in vacuo. The residue was chromatographed on silica gel eluting with methylene chloride to give 4.0 g (83% yield) of the desired thioacetate as an oil.

The NMR-25 spectrum of the title compound (as deuterochloroform solution) had peaks at 2.36 (s, 3H); 3.16 (d. 2H); 3.94 (c, 4 H); and 5.0 (t, 1H) ppm.

Preparation M

2-Oxo-1,3-dioxacyclopent-4-ylmethylthioacetate Diisopropylazodicarboxylate (3.9 mL, 0.02 mol) was added to a solution of 5.2 g (0.02 mol) of triphenylphosphine in 50 mL. anhydrous tetrahydrofuran and cooled to 0 ° C under a nitrogen atmosphere. The solution was stirred at 0 ° C for 30 min during which time a precipitate formed. To this mixture was added dropwise at 0 ° C a solution of 1.18 g (0.01 mol) of glycerol carbonate and 1.4 ml (0.02 mol) of thioacetic acid in 20 ml of anhydrous tetrahydrofuran. The mixture was stirred at 0 ° C for 1 h and then at room temperature for 2.5 h. The mixture was evaporated in vacuo and the residue partitioned between 70 ml of ethyl acetate and 70 ml of water. The ethyl acetate layer was washed with two 50 ml portions of saturated aqueous sodium bicarbonate solution, 50 ml of water and 50 ml of saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate and evaporated in vacuo. The residue was chromatographed on silica gel eluting with methylene chloride to give 600 mg of crude material. The crude product was further purified by chromatography on silica gel eluting with 3: 1 hexane / ethylene acetate to give 220 mg (13% yield) of the desired thioacetate as an oil.

The NMR spectrum of the title compound (as deuterochloroform solution) peaked at 2.4 (s, 3H); 3.25 (d. 2H); and 3.94-5.07 (c, 3H) ppm.

Claims (7)

30 81 355 A process for preparing an antibacterial 2-dioxacycloalkane-thiopenem derivative of the formula I 5 OH f 5 = h3c jzTJC o COOH 10 or a pharmaceutically acceptable salt thereof, wherein R is 15 fB 1 -, alk) rT YY A is carbonyl or methylene; 20. is alkylene of 2 to 5 carbon atoms; alk is alkylene of 1 to 6 carbon atoms; and n is 0 or 1; characterized in that the compound of formula 9C OH 25. H Hl 1111C /, - S S-R / Υ-Ϋ Y Process according to Claim 1, characterized in that B is ethylene, A is methylene, n is 1 and alk is methylene. Process according to Claim 2, characterized in that R is 1,3-dioxacyclopent-4-ylmethyl or 1,3-dioxacyclopent-2-ylmethyl. 3. COORj wherein R is as defined above and R3 is a benzyl or p-nitrobenzyl group, the group R3 is removed by hydrogenation and, if desired, the resulting compound of formula I is converted into a pharmaceutically acceptable salt. Process according to Claim 1, characterized in that A is carbonyl, n is 1 and alk is methylene. Process according to Claim 4, characterized in that R is 2-oxo-1,3-dioxacyclopent-4-ylmethyl. Process according to Claim 1, characterized in that B is propylene, A is methylene or carbonyl and n is 0. Process according to Claim 6, characterized in that R is 1,3-dioxacyclohex-5-yl or 2-oxo-1,3-dioxacyclohex-5-yl. 32 81 355