NO161065B - ANALOGY PROCEDURE FOR THE PREPARATION OF THERAPEUTIC ACTIVE 2-AZETIDINONES. - Google Patents

Description

The present invention relates to an analogous method for the production of therapeutically active 2-azetidinones with the general formula I

in

in which Rx is

where R 13 is hydrogen or C 1 -C 4 alkyl containing a carboxyl group or a C 1 -C 4 alkyl or benzyl ester thereof, R 2 is hydrogen or (^-4 alkoxy,

R 3 and R 4 are the same or different and are hydrogen or C 1 - C 4 alkyl,

as well as salts thereof and stereoisomeric forms thereof.

Salts of the substituent "-SO 3 H " on the nitrogen atom in the β-lactams produced according to the invention include all sulfonic acid salts. Pharmaceutically acceptable salts are of course preferred, although other salts are applicable for purification of the products produced according to the invention or as intermediates for the production of pharmaceutically acceptable salts. The cationic part of the sulfonic acid salts produced according to the invention can be obtained from either organic or inorganic bases. Such cationic portion includes, but is not limited to, the following ions: ammonium; substituted ammonium ion, such as alkylammonium (eg tetra-n-butylammonium, hereinafter referred to as tert-butylammonium); alkali metal, such as lithium, sodium and potassium; alkaline earth metals such as calcium and magnesium; puridinium; dicyclohexylammonium;

hydrabaminium; benzathine; N-methyl-D-glucaminium.

As will be described later, the β-lactams are produced synthetically according to the invention. The non-alkylated, 4-unsubstituted β-lactams of formula I, i.e. the compounds of formula I where R 2 , R 3 and R 4 are hydrogen can be prepared by using 6-amino-penicillanic acid or a 6-acylaminopenicillanic acid as starting material. The β-lactams of formula I where R 2 is alkoxy can be prepared from the corresponding non-alkylated β-lactam. Some of the compounds produced according to the invention can be crystallized or recrystallized from solvents containing water. In these cases, water of hydration may form. The present invention includes a method for producing stoichiometric hydrates

as well as compounds containing varying amounts of water which can be obtained by methods such as e.g. lyophilization.

β-lactams with a sulfonic acid salt substituent in the 1-position and an amino or acylamino substituent in the 3-position contain at least one chiral-centered carbon atom (in the 3-position of the β-lactam core) to which amino or acylamino the substituent is bonded. The present invention is directed towards the production of such β-lactams as described above, where the stereochemistry of the chiral center in the 3-position in the β-lactam core is the same as the configuration at the carbon atom in the 6-position in naturally occurring penicillins (e.g. penicillin G) and as the configuration at the carbon atom in the 7-position in naturally occurring cefamycins (eg cefamycin C).

Also included within the scope of the invention is a method for producing racemic mixtures containing the above-described β-lactams.

β-lactams with a sulfonic acid salt substituent in the 1-position

in the β-lactam core and an amino or acylamino substituent in the 3-position of the β-lactam core has activity against a number of gram-negative and gram-positive organisms. The sulfonic acid salt substituent is essential for the activity of the compounds produced according to the invention. Those compounds where R3

and/or R4 is hydrogen or alkyl, especially methyl, exhibits particularly strong activity.

The compounds produced according to the invention can be used as agents for combating bacterial infections (including infections in the urinary tract and in the respiratory tract) in mammals such as e.g. livestock or pets (e.g. dogs, cats, cows, horses and the like) and in humans.

For combating bacterial infections in mammals, a compound prepared according to the invention can be administered to a mammal in need of it, in an amount of approx. 1.4 mg/kg/day to approx. 350 mg/kg/day, preferably approx. 14 mg/kg/day to approx. 100 mg/kg/day. All administration methods that have been used previously to deliver penicillins and cephalosporins to the sites of infection can also be used for the new family of β-lactams produced according to the invention. Such administration methods include oral, intravenous, intramuscular and as a suppository.

The β-lactam products are prepared according to the invention by a) sulfonating a corresponding intermediate with a hydrogen atom in the 1-position with a pyridine-sulfur trioxide complex or an equivalent thereof according to usual conditions, or b) acylating a corresponding intermediate in which R^ is hydrogen with an acyl group as defined by R^ above according to

common methods,

and if desired transfers acid groups into salts, and/or if desired cleaves racemic mixtures into stereoisomeric forms.

The most commonly used sulfur trioxide complexes are pyridine-sulfur trioxide; lutidine sulfur trioxide; dimethylformamide-sulfur trioxide; and picoline sulfur trioxide. Instead of using a preformed complex, the complex can be formed in situ, e.g. using chlorosulfonyl-trimethylsilyl ester and pyridine as reagents. Alternatively, the sulfonation can be carried out via an intermediate compound such as e.g. by first silylating the nitrogen atom of the β-lactam nucleus and then subjecting the silylated compound to a silyl exchange reaction with trimethylsilyl chlorosulfonate or a similar reagent. Examples of silylating agents are monosilyl trifluoroacetamide, trimethylsilyl chloride/triethylamine and bistrimethylsilyl trifluoroacetamide.

In general, the sulfonation reaction is carried out in the presence of an organic solvent such as pyridine or a mixture of organic solvents, preferably a mixture of a polar solvent such as e.g. dimethylformamide and a halogenated hydrocarbon such as e.g. dichloromethane.

The product that is formed first in the sulfonation reaction is a salt of the sulfonated β-lactam. When pyridine-sulfur trioxide is the sulfonating complex, the first product formed is the P-lactam sulfonated pyridinium salt of the sulfonated ε-lactam where M<+> in the formula below is the pyridinium ion:

These complexes can be converted to other sulfonic acid salts using conventional techniques (eg, ion exchange resins, crystallization or ion-pair extraction). These conversion techniques are also applicable to the purification of the products. Conversion of the pyridine salt to the potassium salt using potassium phosphate or potassium ethyl hesanoate; to the tetrabutylammonium salt using tetrabutylammonium hydrogen sulfate; or to a zwitterion (M"1" = hydrogen) using formic acid; are particularly applicable.

It should be understood that the sulfonation reaction which introduces the sulfo group on the nitrogen atom in the β-lactam core can be carried out at different stages of the synthesis, including introduction before formation of a β-lactam core, where such a procedure is followed as indicated below. The sulfonation reaction is carried out in the presence of solvents described earlier and usually at room temperature. When the amino function is present, it preferably takes place with a protected amino function.

Using a benzyloxycarbonyl protecting group as an example, the sulfonation reaction can be visualized as follows:

Other protecting groups can be used to protect the amine function, e.g. a t-butyloxycarbonyl group, a simple acyl group such as acetyl or benzoyl or phenylacetyl,

a triphenylmethyl group, or by having the amino function in the form of an azide group. The desired acyl group (R^) can then be attached by means of a conventional acylation reaction.

Examples of acylation techniques for the conversion of a

compound of formula III to a product of formula I comprises reaction with a carboxylic acid (Rj^-OH), or corresponding carboxylic acid halide or carboxylic anhydride. When R 2 is alkoxy, the acylation is best carried out using an acid chloride or acid bromide. The reaction with a carboxylic acid proceeds most easily in the presence of a carbodiimide such as e.g. dicyclohexylcarbodiimide and a substance which can form an active ester in situ such as e.g. N-Nydroxybenzotriazole. In those cases where the acyl group (R^ contains reactive functionality (such as amino or carboxyl groups) it may be necessary to first protect these functional groups, then perform the acylation reaction and finally remove the protecting group from the resulting product. Alternatively, the sulfonation reaction can is carried out with the acyl group in place, i.e.:

When R2 is lower alkoxy, there can be a further variation in that the lower alkoxy group R2 can be introduced after the sulfonation as well as before the sulfonation using the conventional method of chlorinating the acylated nitrogen atom in the 3-position followed by reaction with a lower alkoxide:

The acyl groups in the above reaction also include easily removable groups that function as a protecting group and which can be removed after the reaction to give the "deacylated" product (-NH2).

An excellent source for the 0-lactara starting materials are the 6-amino-penicillanic acids and the 7-aminocephalosporin acids which may optionally have a 6- alkoxy or 7- alkoxy substituent, respectively. These compounds have the formulas:

respectively, where R_ is hydrogen or alkoxy and is hydrogen or acyl. By using methods described in the literature, 3-amino-2-azetidinones can be prepared; see for example Chem. Soc. Special Publication No. 28, page 288 (1977); TheCehmistry of Penic.illins , PrincetonUniv. Press, page 257, and Synthesis, 494 (1977).

First, sulfur is removed from the 6-amino-penicillanic acid or the 7-amino-cephalosporanic acid by reduction with Raney nickel. The reaction can be run in water under reflux conditions; the resulting compound has the structural formula:

Replacement of the carboxyl group in the compound of formula XXVI with an acetate group followed by hydrolysis gives a 3-amino-3-alkoxy-2-azetidinone of formula I where R 1 is hydrogen or acyl, R 2 is hydrogen or lower alkoxy and R 1 and R 4 are hydrogen. Treatment of a compound of formula XXVI with cupric acetate and lead acetate in an organic solvent (eg acetonitrile) replaces the carboxyl group with an acetate group. Hydrolysis of the resulting compound can be carried out using potassium carbonate in the presence of sodium borohydride.

introduction of a sulfo group in the 1-position in the above 3-amino-3-alkoxy-2-azetidinone can be accomplished by reacting the intermediate with a complex of dimethylformamide and sulfur trioxide.

A 3-azido-2-azetidinone starting material can be prepared by first reacting an olefin of the formula:

with a halosulfonyl isocyanate (preferably chlorosulfonyl isocyanate) of the formula: to give an azetidinone of the formula:

Reductive hydrolysis of an azetidinone of formula XXIX gives an N-unsubstituted β-lactam of the formula:

For a more detailed description of the above reaction sequence, reference can be made to the literature; see for example Chem. Soc. Fox.,

5, 181 (1976) and J. Org. Chem., 35, (197o) .

An azido group can be introduced in the 3-position of an azetidinone

of formula XXX (or the sulfonated equivalent) by reaction between the compound and an arylsulfonyl azide (such as toluenesulfonyl azide) for. to obtain a starting azetidinone of the formula:

The reaction proceeds best by first protecting the azetidinone nitrogen with a silyl residue (e.g. t-butyldimethylsilyl or t-butylphenylsilyl), then generating the anion at the 3-position of the core with a strong organic base (e.g. lithium -diisopropylamine) at low temperature and then treat the anion with toluenesulfonylazide. The resulting intermediate is cooled with trimethylsilyl chloride, and subsequent acid hydrolysis or fluoride solvolysis of the N-protecting group gives the compound of formula XXXI.

Alternatively, the compound of formula XXXI can be obtained by first reacting a primary amine of the formula:

with an aldehyde of the formula R^CH=0 to give the corresponding Schiff base. A [2+2) cyclization addition with an activated form of -azidoacetic acid gives a 3-azido-2-azetidinone of the formula: where 0 is:

Oxidative removal of the Q substituent gives the compound of formula

XXXI.

The 3-Acylamino-2-azetidinones can be obtained by first reducing a 3-azido-2-azetidinone of formula XXXI to obtain the corresponding 3-amino-2-azetidinone and then acylating the 3-amino-2-azetidinone.

As previously mentioned in the cases where R2 is lower alkoxy, the product can be prepared from the corresponding product where R2 is hydrogen. Chlorination of the amide nitrogen in a non-alkylated compound gives an intermediate product with the formula:

Reagents and methods for N-chlorination of amides are known in the field. Examples of reagents are tert-butyl hypochlorite, sodium hypochlorite and chlorine. The reaction can be carried out in an organic solvent (eg a lower alkanol such as methanol) or in a two-phase solvent system (eg water/methylene chloride) in the presence of a base such as sodium borate decahydrate. The reaction is preferably carried out at a reduced temperature.

The reaction between an intermediate of formula XXXI and an alkylating agent, e.g. an alkali metal alkoxide, gives a product of formula I wherein R 2 is alkoxy, in combination with its enantiomer. The reaction can be carried out in an organic solvent, e.g. a polar organic solvent such as dimethylformamide, at reduced temperature.

An alternative synthesis for the preparation of the compounds of formula I where R 2 is alkoxy comprises first alkoxylating an intermediate of formula VI where R^NH is a carbamate (e.g. R^ is benzyloxycarbonyl) and R 2 is hydrogen and then introducing a sulfo group into 1 position in the resulting compound. Chlorination of a compound of formula VI using the procedure described above (for chlorination of a non-alkylated compound of formula I to give a compound of formula XXXII) yields an intermediate of formula:

Using the alkylation procedure described above (for converting a compound of formula XXXII to a product of formula I), and then adding a reducing agent such as e.g. trimethylphosphite, the compound of formula XXXIII can be converted into an intermediate of the formula:

in a combination with its enantiomer.

The above' processes give the products of formula I where R 2 is alkoxy as a racemic mixture. If desired, the enantiomer with the R configuration can be isolated from the racemic mixture using conventional techniques such as e.g. fractional crystallization of a suitable salt with an optically active amine or by ion-pair chromatography using an optically active cation.

Example 1

(S(-3-[[(2-amino-4-thiazolyl)acetyl]amino]-2-oxo-1-azetidine sulfonic acid potassium salt.

A) (S)-3-amino-2-oxo-1-azetidine sulfonic acid-

tetrabutylammonium salt.

(S)-2-oxo-3-[[(phenylmethoxy)carbonyl]amino]-1-azetidinesulfonic acid tetrabutylammonium salt (2 g: see example 4) is dissolved in 100 ml of dimethylformamide and hydrogenated for approx. 31 minutes with 1 g palladium-on-charcoal (10%) as catalyst. The catalyst is filtered off and the dimethylformamide is removed leaving the title compound as an oil. NMR (CDCl 3 ) 3.82 (1H, t, j =5.5), 4.05 (d. 1H, d of d, j =5.5, 2.5 eps). B) (S)-3-[[(2-amino-4-thiazolyl)acetyl]amino]-2-oxo-1-azetidine sulfonic acid potassium salt.

The above-mentioned compound (2 g), 0.5 g of aminothiazole-acetic

acid and 0.4 g of hydroxybenzotriazole are stirred at 0°C in 100 ml of dry dimethylformamide, while a solution of 0.7 g of dicyclohexyl barobodiimide in 10 ml of dimethylformamide is added dropwise. After the addition is complete, stirring is continued for 12 hours at ( 20°C. Insoluble urea is filtered off and the solvent is evaporated in vacuo. The oily residue is treated with a solution of potassium perfluorobutanesulfonate in 21 ml of acetone at room temperature for 15 minutes. After the addition of 200 ml of dimethyl ether the title compound precipitates, and is filtered off, dried and purified using a 300 ml HP-20 chromatography column with water as eluent.The yield is 850 mg of the title compound, m.p.

> 300°C.

Example 2

[3S(Z)]-3-[[(2-amino-4-thiazolyl)[[[hydroxy)phenylmethoxy)-phosphinyl]methoxy]imino]acetyl]amino]-2-oxo-1-azetidine sulfonic acid potassium salt.

(S)-3-amino-2-oxo-1-azetidinesulfonic acid-tetrabutylammonium-

salt (0.8 g; see Example IA) in 30 ml of dimethylformamide, 0.9 g of (Z)-2-amino-oc-[[[hydroxy(phenylmethoxy)phosphiny1]methoxy]imino]-4-thiazoleacetic acid, 0, 3 g of hydroxybenzotriazole and 0.7 g of dicyclo-

hexylcarbodiimide is stirred for 24 hours at room temperature. The precipitated urea is filtered off and the solvent is removed in vacuo. The remaining oil is treated with an equivalent amount of potassium perfluorobutanesulfonate in 10 ml of acetone. The title compound is filtered off and purified using HP-20 resin and water as eluent to give 500 mg, mp 210-215°C, mp.

Example 3

[3S(Z)]-3-[[(2-amino-4-thiazolyl)(ethoxyimino)acetyl]amino]-2-oxol-1-azetidine sulfonic acid potassium salt.

(S)-3-amino-2-oxo-1-azetidinesulfonic acid tetrabutylammonium salt (1.5 g: see Example IA) in 100 ml of dimethylformamide, 0.6 g of hydroxybenzotriazole, 1 g of dicyclohexylcarbodiimide and 0.8 g of (Z)- 2-amino-α-(ethoxyimino)-4-thiazoleacetic acid is stirred at room temperature for 24 hours. The solvent is distilled off and the residue is dissolved in 30 ml of acetone. The urea is filtered off and the mother liquor is treated with a solution of 2 g of potassium perfluorobutanesulfonate in 20 ml of acetone. After adding 200 ml of ether, the title compound is precipitated, filtered off and dried. Purification is accomplished by chromatography using an HP-20 column and water as eluent to obtain 1.1 g of the title compound, mp 180-185°C, mp.

Example 4

[3S(E)]-3-[[(2-amino-4-thiazolyl)(ethoxyimino)acetyl]amino]-2-oxol-1-azetidine sulfonic acid potassium salt.

By following the procedure in Example 3, but replacing (Z)-2-amino-α-(ethoxyimino)-4-thiazoleacetic acid with (E)-2-amino-α-(ethoxyimino)-4-thiazoleacetic acid, the title compound is obtained, m.p. . 160-170°C after freeze drying.

Example 5

[3S(Z)]-3-[[(2-amino-4-thiazolyl)[(2,2,2-trifluoroethoxy)imino]-acetyl1amino1- 2-oxo-1-azetidine sulfonic acid potassium salt.

Following the procedure of Example 3, but replacing (Z)-2-amino-cx-ethoxyimino)-4-thiazoleacetic acid with (Z)-2-amino-cx-[(2,2,2-trifluoroethoxy)imino]- 4-thiazoleacetic acid, the title compound with a melting point of 160-170°C is obtained after freeze-drying.

Example 6

[3S(Z)]-3-[[(2-amino-4-thiazolyl)(methoxyimino)acetyl]amino]-2-oxol-1-azetidine sulfonic acid potassium salt.

(S)-3-amino-2-oxo-1-azetidine sulfonic acid tetrabutylammonium salt (prepared as described in Example IA from 7.9 g of (S)-2-oxo-3-[[(phenylmethoxy)carbonyl]amino]-1 -azetidine sulfonic acid tetrabutylammonium salt) is cooled to 0°C and 3.53 g of (Z)-2-amino-α-(methoxylimino)-4-thiazoleacetic acid is added, followed by a solution of 3.27 g of dicyclohexylcarbodiimide in 10 ml of dimethylformamide . The mixture is stirred for 16 hours at 5°C, filtered and the solvent is removed in vacuo. The residue is dissolved in acetone and filtered. By adding 60 ml of a 10% solution of potassium perfluorobutanesulfonate in acetone, 4.7 g of crude product crystallizes. The crude product is purified by chromatography on HP-20, 100-200 mesh to give 3.0 g of the title compound, mp 235°C.

Example 7

[3S(Z)]-3-[[(2-amino-4-thiazolyl)[[2-(diphenylmethoxy)-1,1-dimethyl-2-oxoethoxy]imino]acetyl]amino]-2-oxo-l -azetidine sulfonic acid- potassium salt.

A solution of 0.005 mol of (S)-3-amino-2-oxo-1-azetidine sulfonic acid tetrabutylammonium salt (see Example IA) and 0.006 mol of (Z)-2-amino-ot-[[2(diphenylmethoxy)-1,l -dimethyl-2-oxoethoxy]imino]-4-thiazoleacetic acid in 60 ml of dimethylformamide is treated with 0.7 g of hydroxybenzotriazole and 1.13 g of dicyclohexylcarbodiimide. The mixture is stirred for approx. 16 hours at room temperature, filtered and the filtrate evaporated. The residue is dissolved in 30 ml of acetone, filtered and treated with 20 ml of a solution of 10% potassium perfluorobutane sulphonate in acetone. After addition of petroleum ether, the title compound is precipitated and treated with ether and filtered to give 3.8 g of product m.p. 190°C, dec.

Example 8

[3S(Z)]-3-[[2-amino-4-thiazolyl][(1-carboxy-1-methylethoxy)imino] acetylaminol-2-oxo-1-azetidine sulfonic acid dipotassium salt.

[3S(Z)]-3-[[(2-amino-4-thiazolyl)[[2-(diphenylmethoxy-1,1-dimethyl-2-oxoethoxy]imino]acetyl]amino]-2-oxo-1- Azetidine sulfonic acid potassium salt (2 g: see Example 7) is suspended in 5 ml of anisole, and 25 ml of trifluoroacetic acid is added at -10° C. The mixture is stirred for 10 minutes at -10° C. Ether (10 ml) is added slowly at -10° C and then 50 ml of petroleum ether is added. The precipitate is filtered off to give 1.6 g of the trifluoroacetic acid salt. This is suspended in 20 ml of water at 0°C, adjusted to pH 5.5 with dilute potassium hydroxide and purified on an HP-20- column The title compound is eluted with water and has a melting point of 225°C, dec.

Example 9

[3S(Z)]-3-[[(2-amino-4-thiazolyl)[[2-diphenylmethoxy]-2-oxoethoxy] imino1 acetyl1aminol- 2-oxo-l- azetidine sulfonic acid potassium salt.

By following the procedure from Example 7, but replacing (Z)-2-amino-α-[[2-(diphenylmethoxy)-1,1-dimethyl-2-oxoethoxy]imino]-4-thiazoleacetic acid with (Z)- 2-amino-α-[[2-(diphenylmethoxy)-2-oxoethoxy]imino]4-thiazoleacetic acid, the title compound is obtained with melting point 180°C, cleavage.

Example 10

[3S(Z)]-3-[[(2-amino-4-thiazolyl)[(2-methoxy-2-oxoethoxy)-imino] acetyl1amino]- 2- oxo- l- azetidine sulfonic acid potassium salt.

(Z)-2-amino-α-[(2-methoxy-2-oxoethoxy)imino]-4-thiazoleacetic acid (1.3 g) and (S)-3-amino-2-oxo-1-azetidine sulfonic acid tetrabutylammonium salt (2.03 g: see example IA) is dissolved in 50

ml of acetonitrile and 1.03 g of dicyclohexylcarbodiimide dissolved in 5

ml of acetonitrile is added dropwise at 0°C. After stirring for 15 hours and filtering off the dicyclohexylurea, the solvent is distilled off. The remaining oil residue is dissolved in acetone and treated with the equivalent amount of potassium perfluorobutane sulphonate. The title compound is isolated and purified by column-

chromatography on HP-20 using water as eluent to give the title compound mp 195-198°C.

Example 11

[3S(Z)]-3-[[2-amino-4-thiazolyl)[[(diethoxyphosphinyl)-methoxy] iminolacetyl] aminol- 2-oxo-l-azetidine sulfonic acid potassium salt.

(S)-3-amino-2-oxo-1-azetidinesulfonic acid tetrabutylammonium salt (2.25 g: see Example IA) in 100 ml of dry dimethylformamide is treated with 1.87 g of (Z)-2-amino-α-[[ (diethoxyphosphinyl)methoxy]imino]-4-thiazoleacetic acid, 0.75 g of hydroxybenzotrizole and 2.29 g of dicyclohexylcarbodiimide for 12 hours with stirring. The precipitated urea is filtered off and the solvent is removed in vacuo. The remaining oil is treated with an equivalent amount of potassium perfluorobutanesulfonate in 20 ml of acetone. After addition of ether, the title compound is precipitated and filtered off in an amount of 2.77

g raw product. Purification of this crude product by column chromatography using HP-20 and water/acetone (9:1) as eluent gives the title compound with melting point 155-160°C, split.

Example 12

[3S(Z)]-3-[[(2-amino-4-thiazolyl)[[2-(1,1-dimethylethoxy]-2-oxo-1-phenylethoxy]imino]acetyl]amino]-2-oxo -1-azetidine sulfonic acid potassium salt.

(S)-3-amino-2-oxo-1-azetidinesulfonic acid tetrabutylammonium salt (2.25 g: see example IA) in 60 ml of dimethylformamide is stirred at room temperature with 2.4 g of (Z)-2-amino-a -[[2-(1,1-dimethylethoxy)-2-oxo-1-phenylethoxy]imino]-4-thiazoleacetic acid, 1 g of hydroxybenzotriazole and 1.5 g of dicyclohexylcarbodiimide for 12 hours. The solvent is removed in vacuo and the residue is dissolved in 50 ml of acetone. The precipitated urea is filtered off and the mother liquor is treated with an equivalent amount of potassium perfluorobutane sulphonate. After addition of ether, the title compound crystallizes and is filtered off. Purification of the compound is achieved by means of HP-20 column chromatography with water/acetone (7:3) as eluent whereby 1 g of product is obtained which melts >250°C, split.

Example 13

[3S(Z)]-3-[[2-amino-4-thiazolyl][(1H-tetrazol-5-ylmethoxy)-iminolacetyl-1aminol-2-oxo-1-azetidine sulfonic acid potassium salt.

(S)-3-amino-2-oxo-1-azetidine sulfonic acid tetrabutylammonium salt (1.9 g: see Example. IA) i; 60 ml of dimethylformamide is treated with acetic acid, 0.7 g of hydroxybenzotriazole and 1.4 g of dicyclohexylcarbodiimide with stirring for 24 hours. After solvents have been removed in vacuo, the residue is dissolved in acetone and the precipitated urea is filtered off. The mother liquor is treated with an equivalent amount of potassium perfluorobutane sulfonate in 10 ml of acetone. The title compound is precipitated by adding 200 ml of ether. Purification is achieved by means of HP-20 column chromatography and water as eluent and 1.05 g of product is obtained which melts at 250°C, split.

Example 14

[3S(Z)]-3-[[2-amino-4-thiazolyl][(phenylmethosky]imino]acetyl] aminol- 2-oxo-l-azetidine sulfonic acid potassium salt.

(S)-3-amino-2-oxo-1-azetidinesulfonic acid tetrabutylammonium salt (1.5 g: see Example IA), 1.23 g (Z)-2-amino-α-[(phenyl-methoxy ]imino) -4-thiazoleacetic acid, 0.57 g of hydroxybenzotriazole and 1.14 g of dicyclohexylcarbodiimide are stirred in 60 ml of dimethylformamide at room temperature for 24 hours. The precipitated urea is filtered off, the solvent is removed and the residue is treated with an equivalent amount of potassium perfluorobutanesulfonate in 10 ml of acetone. After addition of ether (200 ml) precipitates the title compound, it is filtered off and purified by means of HP-20 column chromatography with water/acetone (9:1) as eluent to obtain 1 g of material melting at 200°C, split.

Example 15

[3S(Z)]-3-[[(2-amino-4-thiazblyl)[(carboxymethoxy)imino]-acetyl] aminol-2-oxo-l-azetidine sulfonic acid potassium salt (1:1).

[3S(Z)-3-[[(2-amino-4-thiazolyl)[[2-(diphenylmethoxy)-2-oxoethoxy]imino]acetyl]amino]-2-oxo-1-azetidine sulfonic acid potassium salt (1: 1) (1.3 g: see example 9) is mixed with 5 ml of anisole. At -15°C, 25 ml of trifluoroacetic acid is added and

the mixture is stirred for 10 minutes. Ether (100 ml) is added slowly at -10°C and then 50 ml of petroleum ether. The precipitate is suspended with cooling in 20 ml of water and adjusted to pH 5.0 with dilute potassium hydroxide. The product is purified by chromatography on an HP-20 column and 3.0 g of the title compound is obtained, which has a melting point of 230-235°C, split.

Example 16

[3S(Z)]-3-[[2-amino-4-thiazolyl)[[(2-oxo-2-phenylmethoxy)-ethoxy]imino]acetyl]amino]-2-oxo-1-azetidine sulfonic acid potassium salt

By following the procedure from Example 7, but replacing (Z)-2-amino-α-[[2-(diphenylmethoxy-1,1-dimethyl-2-oxoethoxy]imino]-4-thiazoleacetic acid with (Z)-2- amino-a-[[2-oxo-2-(phenyl-methoxy)-ethoxy]imino]-4-thiazoleacetic acid, the title compound is obtained with melting point approx. 170°C, diss.

Example 17

[3S(Z)-3-[[(2-amino-4-thiazolyl)(hydroxyimino)acetyl]amino]-2-oxol-1-azetidine sulfonic acid potassium salt.

A solution of 0.6 grams of 90% hydroxybenzotriazole in 100 ml of dimethylformamide is stirred for one hour with 10 grams of 4A molecular sieves, filtered and the filtrate is added to a solution of 0.004 mol of (S)-3-amino-2-oxo -1-azetidine sulfonic acid tetrabutylammonium salt (see Example IA) in dimethylformamide. (Z)-2-amino-α-(hydroxyimino)-4-thiazoleacetic acid (0.89 g) is added, followed by the addition of 0.91 g of dicyclohexylcarbodiimide. The mixture is stirred for approx. 16 hours, evaporated in vacuo and the residue dissolved in 20 ml of acetone and filtered. Addition of a solution of potassium perfluorobutanesulfonate causes the title compound to precipitate. Chromatography on HP-20 resin gives 0.44 g of product, m.p. >240°C.

Example 18

[3S(Z)]-3-[[(2-amino-4-thiazolyl)[(carboxymethoxy)imino]-acetyl] aminol- 2- oxo- l- azetidine sulfonic acid potassium salt.

[2S(Z)]-3-[[(2-amino-4-thiazolyl)[[2-oxo-2-(phenylmethoxy)ethoxy]imino]acetyl]amino]-2-oxo-1-azetidine sulfonic acid potassium -

salt (0.1 g: see example 16) is dissolved in a mixture of 5 ml of ethanol and 5 ml of water and hydrogenated at room temperature in the presence of 0.2 g of 10% palladium on charcoal. After 2 hours, the catalyst is filtered off and the remaining solution freeze-dried to give the title compound, m.p. 235°C (split).

Example 19

[3S(Z)]-3-[[(2-amino-4-thiazolyl)[[2-(1,1-dimethylethoxy)-1-(methylthio)-2-oxoethoxy]imino]acetyl]amino]-2 -oxo-1-azetidine sulfone<y>re-potassium salt<.>

By following the procedure from Example 17, but replacing (Z)-2-amino-α-(hydroxyimino)-4-thiazoleacetic acid with (Z)-2-amino-α-[[2-(1,1-dimethylethoxy)- 1-(methylthio)-2-oxoethoxy]imino]-4-thiazoleacetic acid, the title compound is obtained with melting point 130°C, cleavage

Example 20

[3±(Z)]-3-[[(2-amino-4-thiazolyl)(methoxyimino)acetyl]amino]-3-methoxy-2-oxo-1-azetidine sulfonic acid. potassium salt.

3-Amino-3-methoxy-2-oxo-1-azetidine sulfonic acid tetrabutylammonium salt is dissolved in acetonitrile (20 mo) and pyridine (1 ml)

and added to a vigorously stirred suspension of (Z)-α(methoxyimino)-2-amino-4-thiazoleacetyl chloride in acetonitrile (20 ml) cooled to -5°C. After stirring cold for 1 hour, the mixture is diluted with 0.5 m monobasic potassium phosphate solution (100 ml) (pH

1 the mixture is 4.8) and solvent is removed in vacuo.

The remainder is absorbed in a minimal amount of water containing a small amount of acetone. Chromatography on ion exchange resin (Ag 50WX2, 100-200 mesh, K^ form, 200 ml) gives the crude product as the potassium salt by elution with water. Further purification on HP-20 resin (200 mL) using water as eluent gives 59 mg of product as a powder after trituration with acetonitrile ether and then twice with ether. The product is an amorphous powder that melts slowly and decomposes above 150°C.

Analysis calculated for <C>i0H^2N5°7SK: c»28.77: H, 2.90: N, 16.78: S, 15.36: K, 9.37

Found: C, 27.77: H, 2.82: N, 15.87: S, 13.63: K, 10.11

Example 21

[3S-[3a(Z), 43]]-2-[[(2-amino-4-thiazolyl)(methoxyimino)-acetyl] amino]- 4- methyl- 2- oxo- l- azetidine sulfonic acid potassium salt.

A) (3S-trans)-4-methyl-2-oxo-3-[[(phenylmethoxy)carbonyl]-amino]-1-azetidine sulfonic acid tetrabutylammonium salt. (3S-trans)-4-methyl-2-oxo-3-[[(phenylmethoxy)carbonyl]-amino]-1-azetidine sulfonic acid potassium salt (352.4 mg) is dissolved in 20 ml of water and tetrabutylammonium hydrogen sulfate (373.5 mg ) is added. The aqueous solution is extracted three times with methylene chloride and the combined extracts are dried over sodium sulfate. After removal of the solvent, 534.6 mg of the title compound are obtained. B) [3S-[3α(Z),43]]-3-[[(2-amino-4-thiazolyl)methoxyimino)-acetyl1amino]-4-methyl-2-oxo-1-azetidine sulfonic acid potassium salt.

A solution of 534.6 mg of (3S-trans)-4-methyl-2-oxo-3-[[(phenylmethoxy)carbonyl]amino]-1-azetidinesulfonic acid tetrabutylammonium salt in 20 ml of dimethylformamide is hydrogenated with 220 mg of 10% palladium on coal at atmospheric pressure for 2.75 hours: absorption of hydrogen is 26.3 ml. The mixture is filtered and washed twice with 2.5 ml of dimethylformamide. The filtrate and the washing liquids (total approx. 25 ml) are stirred under nitrogen with 161 mg of (Z)-α-(methoxyimino)-2-amino-4-thiazoleacetic acid, 136 mg of N-hydroxy-benzotriazole and 164.8 mg of dicyclohexylcarbodiimide. The mixture is stirred under nitrogen for approx. 16 hours. The dimethylformamide is removed in vacuo and the rubber residue is dissolved in acetone and filtered to remove urea. A solution containing 272 mg (0.8 mmol) of perfluorobutanesulfonic acid potassium salt in 0.8 ml of acetone is added to the filtrate. The slurry is diluted with an equal volume of ether and filtered to give 325.5 mg of crude product which is purified by chromatography on 75 ml of HP-20AG. Elution with 400 ml water and 400 ml (9:1) water:acetone mixture (50 ml fractions) gives 335 mg in fractions 3 to 10. After trituration with acetone-hexane, 97.3 mg of an analytical sample is obtained from fractions 3 -5. Similar trituration of fractions 6-10 gives an additional 90.4 mg of product as a solid.

Analysis calculated for Ci0<H>i2<N>5<0>6s2K: c>29.92: H, 3.01: N, 17.45: S, 15.97: K, 9.74,

Found: C, 30.32: H, 3.49: N, 15.82: S, 13.95: K, 10.45

NMR(D 2 O) 1.57 (3H, d, j=7), 3.97 (3H.S), 4.30 (1H, d of q, j =7.3), 4.70 (1H, d ,j=7), 6.95 ppm (1H,S).

Example 22

[3S-[3a(Z),4B]]-3-[[(2-amino-4-thiazolyl)[(1-carboxy-1-methyl-ethoxy)imino]acetyl]amino]-4-methyl-2 -oxo-1-azetidine sulfonic acid dipotassium salt.

A) N-benzyloxy-t-boc-threonine-amine

A solution of 8.76 g of t-boc-threonine and the free amine from

6.4 g of O-benzylhydroxylamine. HCl (ethyl acetate-sodium bicarbonate release) in 100 ml of tetrahydrofuran is treated with 6.12 g of N-hydroxybenzotriazole and 8.24 g of dicyclohexylcarbodiimide in 20 ml of tetrahydrofuran. The mixture is stirred under nitrogen for 26 hours, filtered and evaporated in vacuo. The residue is chromatographed on a 300 g silica gel column (elution with chloroform and chloroform-ethyl acetate (3:1) gives 7.2 g of compound. Crystallization from ether-hexane gives 4.18 g of the title compound. B) (3S-trans)- N-Benzyloxy-3-t-butoxycarbonylamino-4-methylazetidinone.

A solution of 12.67 g of N-benzyloxo-t-boc-threnoninamide,

11.5 g of triphenylphosphine and 6.23 g of diethyl azodicarboxylate in 380 ml of tetrahydrofuran are stirred under nitrogen for approx. 16 hours. The solution is evaporated and chromatographed on a 900 gram silica gel column. Elution with chloroform-ethyl acetate (3:1) gives 13.69 g of compound which crystallizes with ether-hexane to give 9.18 g of the title compound. C) (3S-trans)-3-t-butoxycarbonylamino-1-hydroxys-4-methylazetidinone.

A solution of 9.18 g of (3S-trans)-N-benzyloxy-3-t-butoxy-carbonylamino-4-methylazetidinone in 300 ml of 95% ethanol is stirred in a hydrogen atmosphere with 1.85 g of 10% palladium on charcoal .

After 141 minutes, the slurry is filtered and evaporated in vacuo. The residue is crystallized from ether-hexane to give 5.12 g of the title compound.

D) (3 S -trans)-3-t-butoxycarbonylamino-

4- methylazetidinone.

A solution of 4.98 g of (3S-trans)-3-t-butoxycarbonylamino-1-hydroxy-4-methylazetidinone in 200 ml of methanol is treated with 132 ml of 4.5 ra ammonium acetate and then 66 ml of 1.5 titanium trichloride and stirred in 4.5 hours. The aqueous solution is diluted with an equal volume of 8% sodium chloride solution and extracted with ethyl acetate to give 3.48 g of crude product. Recrystallization from ether-hexane gives 3.3 g of the title compound.

E) (3S-trans)-3-benzyloxycarbonylamino-4-methyl-azetidinone.

A solution of 3.3 g of (3S-trans)-3-t-butoxycarbonylamino-4-methylazetidinone in 10 ml each of dichloromethane and anisole is cooled to 0°C and 112 ml of trifluoroacetic acid is added. The solution is stirred for 90 minutes and evaporated in vacuo (benzene added and evaporated three times). The residue is dissolved in 70 ml of acetone and the solution is adjusted to pH 7 with a 5% sodium bicarbonate solution. A total of 5.33 g of benzyl chloroformate is added over the course of 1 hour at pH 6.5-7.5. The mixture is stirred for 30 minutes at pH 7, diluted with 100 ml of saturated salt and extracted with ethyl acetate (three 400 ml portions). The residue obtained by evaporation is chromatographed on a 1 liter silica gel column. Elution with chloroform-ethyl acetate (4:1) gives 2.19 g of compound. Crystallization from ether-hexane gives 1.125 g of the title compound. F) (3S-trans)-4-methyl-2-oxo-3-[[(phenylmethoxy)carbonyl]-amino1-1-azetidine sulfonic acid tetrabutylammonium salt.

A solution of 600 mg of (3S-trans)-3-benzyloxycarbonylamino-4-methylazetidinone in 2 ml of dimethylformamide is added. The solution is stirred at room temperature under nitrogen for 1 hour and poured into 80 ml of cold 0.5m monobasic potassium phosphate (adjusted to pH 5.5). The solution is extracted with three 50 ml portions of methylene chloride (discarded) and 868 mg of tetrabutylammonium bisulphate is added. The resulting solution is extracted with four 75 ml portions of methylene chloride. The combined organic layer is washed with 8% aqueous sodium chloride, dried and evaporated in vacuo to give 1.54 g of the title compound. G) [3S-[3a(Z),4P]]-3-[[(2-amino-4-thiazole)[(1-diphenyl-methoxycarbonyl-1-methylethoxy)imino]acetyl]amino]-4-methyl - 2-oxo-l-azetidine sulfonic acid potassium salt.

A solution of 1.54 g of (3S-trans)-4-methyl-2-oxo-3-[[(phenyl-methoxy)carbonyl]amino]-1-azetidinesulfonic acid tetrabutylammonium salt in 45 ml of dimethylformamide is stirred in a hydrogen atmosphere with 800 mg of 10% palladium on charcoal for 2 hours. The catalyst is filtered off and phenylmethoxycarbonyl-1-methylethoxy)imino]-4-thiazoleacetic acid, 0.4 g of N-hydroxybenzotriazole and 580 mg of dicyclohexylcarbodiimide. The slurry is evaporated in vacuo and the residue is triturated with 20 ml of acetone and filtered. The filtrate (plus 2 ml of washing liquid) is treated with 868 mg of potassium perfluorobutane sulphonate in 3 ml of acetone. Dilution with 75 ml of ether gives a solid which is isolated by decantation of the mother liquor, trituration with ether and filtration to give 0.91 g of the title compound. The mother liquor is diluted with a further 100 ml of ether to give a second yield, 0.45 g, of the title compound. H) [3S-[3a(Z) ,43]]-3-[[(2-amino-4-thiazolyl)[1-carboxy-1-methyloxy)imino]acetyl]amino]-4-methyl-2- oxo-1-acetidine sulfonate potassium salt.

A slurry of 140 mg of [3S-[3a(Z),43]]-3-[[(2amino-4-thiazolyl)[(1-diphenylmethoxycarbonyl-1-methylethoxy)imino]acetyl]-amino]-4-methyl -2-oxo-1-azetidine sulfonic acid potassium salt (first yield) in 0.5 ml of anisole is stirred at -12°C under nitrogen and 2.5 ml of cold (-10°C) trifluoroacetic acid is added. After 10 minutes, 10 ml of ether and 5 ml of hexane are added and the resulting slurry is stirred for 5 minutes at -12°C and allowed to warm to room temperature. The solid is isolated by centrifugation and washed twice with ether. A solution of this solid in 5 ml cold water is immediately adjusted to pH 5.5 with 0.4 N potassium hydroxide and then applied to an 80 ml HP-20AG column. Elution with water gives 72 mg of the title compound in fractions (10 ml) 7-11 after evaporation (acetonitrile is added and evaporated 3 times) and trituration with ether, m.p. 250°C, split.

Analysis calculated for C13<H>15N508S2K2: C, 30.51: H, 2.95: N, 13.69: S, 12.53: K, 15.28,

Found: C, 29.63: H, 3.20: N, 12.96: S, 11.94: K, 12.78. NMR(D 2 O) 1.46 (S, 6H), 1.58 (1H,d,^=7) 4.28 (1H, d of q,y= 7, 2.5), 4.67 (1H, d, ^=2), 6.95 ppm (S, 1H).

The remaining 1.22 g of [3S-[3oc(Z),4P]]-3-[[(2-amino-4-thiazolyl)[(1-diphenylmethoxycarbonyl-1-methylethoxy)imino]acetyl]-amino]- 4-Methyl-2-oxo-1-azetidine sulfonic acid potassium salt (yields 1 and 2) is treated as above (4.2 ml anisole, 16 ml trifluoroacetic acid, 13 min at -15°C). Chromatography on a 300 ml HP-20AG column gives 694 mg of the title compound in fractions (60 ml) 6-9 after treatment as above.

Example 2 3

By following the procedure from Example 15, but substituting [3S(Z)-3-[[(-amino-4-thiazolyl)[[2-(diphenylmethoxy)-2-oxoethoxy]-imino]acetyl]amino]-2- oxo-1-azetidine sulfonic acid potassium salt with A, B is obtained.

A = [3S(Z)]-3-[[(2-amino-4-thiazolyl)[[2-(1,1-dimethylethoxy)-1-(methylthio)-2-oxoethoxy1imino]acetyl]amino]-2 -oxo-1-acetidinesulfonic acid potassium salt (see example 18)

B = [3S(Z)-3-[[(2-amino-4-thiazolyl)[[carboxy-(methylthio)methoxy]

imino]acetyl]amino]-2-oxo-1-azetidine sulfonic acid potassium salt (1:2), melting point 165°C, split

Example 24

[3oc(Z),4P]-3-[[(2-amino-4-thiazolyl)(methoxyimino)acetyl]amino]-4-methyl-2-oxo-1-azetidine sulfonic acid potassium salt.

A solution of 51.8 mg of (cis)-4-methyl-2-oxo-3-[[(phenyl-methoxy)carbonyl]amino]-1-azetidine sulfonic acid potassium salt and 51

mg of tetra-n-butyl-ammonium bisulphate in 5 ml of water is extracted with methylene chloride (four 10 ml portions) to give 81 mg of oil.

This is stirred in 4 ml of dimethylformamide. The catalyst is filtered off and washed with 1 ml of dimethylformamide. The filtrate and washing liquid are combined and stirred for approx. 16 hours with 31 mg of (Z)-2-amino-α-(methoxyimino)-4-thiazoleacetic acid, 27 mg of N-hydroxybenzotriazole and 31.5 mg of dicyclohexylcarbodiimide. The solution is evaporated in vacuo and the residue is triturated with 3 ml of acetone. The resulting slurry is centrifuged and the liquid is treated with 51 mg of potassium perfluorobutane sulfonate. Dilution with 5 ml of ether and filtration gives a solid. Chromatography on HP-20AG (41 ml) gives Rydon positive material in fractions (20 ml) 3-5 (elution with water). Evaporation and ether trituration gives 23 mg of product as a hygroscopic solid.

Analysis calcd for C10Hi2<N>506s2K: c>29.91: H, 3.01: N, 17.44 Found: C, 29.30: H, 3.31: N, 16.66 NMR(D2O) 1 .40(3H, d,^=7), 3.97 (3H,S), 4.46 (1H, apparently pentet,=7) , 5.37 (1H, d, j=7), 6.97 ppm (1H.S).

Example 25

[3S-[3a(Z),4P]]-3-[[2-amino-4-thiazolyl)methoxyimino)acetyl]-aminol- 4- methyl- 2-oxo-l-azetidine sulfonic acid potassium salt.

A solution of 201 mg of (Z)-2-amino-α-(methoxyimino)-4-thiazoleacetic acid and 153 mg of N-hydroxy-benzotriazole monohydrate in 3 ml of dimethylformamide is treated with 206 mg of dicyclohexylcarbodiimide. The mixture is stirred at room temperature for 20 minutes under nitrogen and a solution of 180 mg of (3S-cic)-3-amino-4-methyl-2-oxo-1-azetidine sulfonic acid and 0.14 ml of triethylamine in 2 ml of dimethylformamide is added (a further 1 ml of dimethylformamide used for rinsing) and the mixture is stirred for approx. 16 hours. The slurry is evaporated in vacuo, triturated with 12 ml of acetone, centrifuged and the liquid is treated with 338 mg of potassium perfluorobutane sulphonate. Dilution with 10 ml of ether and filtration gives a solid product which is chromatographed on 200 ml of HP-20 resin eluting with water. Fractions (20 mL each) 18-30 are combined and lyophilized to give 274 mg of the title compound as a hygroscopic solid.

Analysis calculated for Cl0<H>12<N>5<O>6S2K: C, 29.91: H, 3.01: N, 17.44 Found: C, 30.03: H, 3.21: N, 17, 06 NMR(D2O) 1.40 (3H, d,^=6.5), 3.98(3H,S), 4.48 (1H, d of t, j

-6.4, 5.5), 5.36(1H, d,y=5.5) 6.97 (1H.S). Example 26 [3S-[3a(Z),4B]]-3-[[(2-amino-4-thiazolyl)[[1,1-dimethyl-2-[(4-nitrophenyl)methoxy]-2-ocosetoxy]imino ]acetyl]amino]-4- methyl- 2- oxo- l- azetidine sulfonic acid potassium salt. To a slurry of (3S-trans)-3-amino-4-methyl-2-oxo-1-azetidinesulfonic acid (0.36 g) in dry dimethylformamide (30 ml) under nitrogen at 26°C is added triethylamine (309 µl) . After approx. 5 minutes a clear solution is obtained and (Z)-2-amino-α-[[1,1-dimethyl-2-[(4-nitrophenyl)methoxy]-2-oxoethoxy]imino]-4-thiazoleacetic acid (0.816 g) is added followed by N-hydroxybenzotriazole (0.334 g) and dicyclohexylcarbodiimide (0.453 g). The mixture is stirred for 12 hours at 26°C, after which the solvent is removed in vacuo, and the residue is triturated with acetone (30 ml). After stirring for 5 minutes, the solids are removed and the filtrate is treated with potassium perfluorobutanesulfonate (3.680 g) in acetone (5 ml). Addition of ether (ca. 40 ml) gives a precipitate which is collected and dried in vacuo (1.073 g: second yield 0.066 g: total 1.14 g). Analysis calculated for C2o<H>2l<N>60ios2K*1 H20: c»38.33: H, 3.70: N, 13.41: S, 10.23: K, 6.24 Found: C, 38 .30: H, 3.63: N, 13.41: S, 9.88: K, 5.98. Example 27 [3a(Z),4P]-3-[[(2-amino-4-thiazolyl)[(1-carboxy-1-methyl-ethoxy)imino]acetyl]amino]-4-methyl-2-oxo-1 -azetidine sulfonic acid potassium salt. (1:2). A) [3oc(Z),4P]-3-[[2-amino-4-thiazolyl)[(1-diphenylmethoxycarbonyl-1-methylethoxy)imino]acetyl]amino]-4-methyl-2-oxo-l- azetidine sulfonic acid potassium salt.

A solution of (cis)-4-methyl-2-oxo-3-[[(phenylmethoxy)-carbonyl]amino]-1-azetidine sulfonic acid tetrabutylammonium salt (201 mg: prepared from the corresponding potassium salt as described in Example 24) in 5 ml of dimethylformamide is stirred with 90 mg of 10% palladium on calcium carbonate in a hydrogen atmosphere for 2 hours. The slurry is filtered and the filtrate is stirred for approx. 16 hours with 146 mg of (Z)-2-amino-α-[(1-diphenylmethoxycarbonyl-1-methylethoxy]imino]-4-thiazoleacetic acid, 73 mg of dicyclohexylcarbodiimine and 51 mg of N-hydroxybenzotriazole under nitrogen. The slurry is evaporated in vacuo and triturated with 4 ml of acetone. The slurry is filtered and the solid is washed twice with 2 ml portions of acetone. The filtrate and washings are combined and treated with 113 mg of potassium perfluorobutanesulfonate. Dilution with 24 ml of ether gives a solid which is isolated by centrifugation and washed three times with ether for to give 186 mg of the title compound B) [3a(Z),4P]-3-[[(2-amino-4-thiazolyl)[(1-carboxy-1-methyl-ethoxy)imino]acetyl]amino]- 2-methyl-4-oxo-1-azetidine sulfonic acid potassium salt (1:2).

A slurry of 186 mg of [3α(Z),4P]-3-[[(2-amino-4-thiazolyl)[(1-diphenylmethoxycarbonyl-1-methylethoxy)imino]acetyl]-amino]-4-methyl-2 -oxo-1-azetidine sulfonic acid potassium salt in 0.6 ml of distilled anisole is cooled to 12°C and 3.0 ml of distilled trifluoroacetic acid (at -10°C) is added. The solution is stirred for 10 minutes and 12 ml of ether followed by 6 ml of hexane are added.

After 5 minutes at -10°C and stirring for 15 minutes at ambient temperature, the solid is isolated by centrifugation and washed four times with ether to give 141 mg of material.

This is dried in a vacuum, pulverized, dissolved in 5 ml of cold water and immediately adjusted to pH 5.6 with 0.4n potassium hydroxide. The solution is applied to a 100 ml HP20AG column and eluted with water. Fractions (10 ml) 8-12 are combined and evaporated in vacuo (acetonitrile is added three times and evaporated). The residue was triturated with ether to give 101.7 mg of product as a hygroscopic solid. Analysis calculated for<C>i3<N>i5<N>508S2<*>2K: C, 30.51: H, 2.95: N, 13.69: S, 12.53: K, 15.28

Found: C, 30.11: H, 3.26:

N, 13.35: S, 12.12: K, 15.02.

Example 28

[3S-[3a(Z),4ø]]-3-[[(2-amino-4-thiazolyl)-[(1-carboxy-1-methyl-ethoxy) imino] acetyl] aminol- 4- methyl1- 2 - oxo-1-azetidine sulfonic acid.

[3S-[3a(Z),4P]]-3-[[(2-amino-4-thiazolyl)-[(1-carboxy-1-methylethoxy)imino]acetyl]amino]-4-methyl-2- oxo-1-azetidine sulfonic acid dipotassium salt (87.3 mg: see example 22) is dissolved in 1.38 ml

water, cooled to 0°C, treated with 0.34 ml of ln hydrochloric acid and the resulting crystals separated by centrifugation. The wet solid is dissolved in methanol, filtered, concentrated to approx. 0.5 ml and mixed with 1 ml of water to give 55.9 mg of the title compound.

Example 29

[3S-[3a(Z),46]]-3-[[(2-amino-4-thiazolyl)-[(1-carboxy-1-methyl-ethoxy)imino]acetyl]amino]-4-methyl- 2-oxo-1-azetidine sulfonic acid sodium salt.

A 99.7 mg sample of [3S-[3a(Z) ,43]]-3-[[(2-amino-4-thiazolyl)-[(1-carboxy-1-methylethoxy)imino]acetyl]amino] -4-methyl-2-oxo-1-azetidinesulfonic acid is mixed with 0.207 mL of 1N sodium hydroxide and the resulting mixture is gently heated to dissolve the remaining solid. Water is azeotropically removed with acetonitrile and the residue is crystallized from a mixture of 0.5 ml of methanol (to dissolve the residue) and 1 ml of acetonitrile to give 81.8 mg of solid. A second recrystallization from 0.8 ml methanol gives 47.9 mg, a third from 0.27 ml methanol and 0.24 ml absolute ethanol gives 44.8 mg, and a fourth from 0.225 ml methanol and 0.225 ml absolute ethanol gives 38 .8 mg. The solid is dried at 20°C and 0.01 mm Hg for 18 hours and then equilibrated with atmospheric humidity for 24 hours to give 40.9 mg of the title compound.

Example 30

[3S-[3a(Z),43]]-3-[[(2-amino-4-thiazolyl)-[(1-carboxy-1-methyl-ethoxy)imino]acetyl]amino]-4-methyl- 2-oxo-1-azetidine sulfonic acid potassium salt ( 1:2) A) [3S-[3a(Z),43]]-3-[[(2-amino-4-thiazolyl)[(1-diphenylmethoxy-carbonyl- 1-methylethoxy)imino]acetyl]amino]-4-methyl-2-oxo-1-azetidine sulfonic acid potassium salt.

A solution of 440 mg of (Z)-2-amino-α-[(1-carboxy-1-methyl-ethoxy)imino]-4-thiazoleacetic acid and 153 mg of N-hydroxybenzotriazole monohydrate in 3 ml of dimethylformamide is treated with 206 mg dicyclohexylcarbodiimide. The mixture is stirred at room temperature for 30 minutes under nitrogen and a solution of 180 mg of (3S-cis)-3-amino-4-methyl-2-oxo-1-azetidinesulfonic acid and 0.14 ml of triethylamine in 2 ml of dimethylformamide is added (further 1 ml of dimethylformamide is used for rinsing) and the mixture is stirred for approx. 16 hours. The slurry is evaporated in a vacuum and rubbed out with 12 ml of acetone. The slurry is filtered and the solid is washed with acetone (two 3 ml portions). The combined filtrate and washings are treated with 338 mg of potassium perfluorobutanesulfonate. Dilution with 30 ml of ether gives a gummy solid which slowly solidifies. The solid is filtered off and washed with ether to give 656 mg of the title compound.

B) [3S-[3a(Z),4ø]]-3-[[(2-amino-4-thiazolyl)-[(1-carboxy-1-methylethoxy)imino]acetyl]amino]-4-methyl- 2-oxo-1-azetidine sulfonic acid potassium salt1 ( 1:2)

A slurry of 656 mg of [3S-[3a(Z),4P]]-3-[[(2-amino-4-thiazolyl)[(1-diphenylmethoxycarbonyl-1-methylethoxy)imino]-acetyl]amino]-4 -methyl-2-oxo-1-azetidine sulfonic acid potassium salt in 2.3 ml of distilled anisole is cooled to -12°C and 11.5 ml of trifluoroacetic acid (pre-cooled to -10°C) is added. The solution is stirred for 15 minutes and 46 ml of ether followed by 23 ml of hexane are added. After 5 minutes the solid is filtered off and washed with ether to give 457 mg of a very hygroscopic gum. This is dissolved in 6 ml of cold water and immediately adjusted to pH 5.6 with 0.4N potassium hydroxide solution. The solution is applied to a 200 ml HP-20 resin and eluted with water. Fractions (50 mL each) 7-11 are combined and lyophilized to give 239 mg of the title compound as a solid.

Analysis Calcd for C^HisOgNsS^* 1/2 H2O: C, 29.99: H, 3.10: N, 13.45: S, 12.32, Found: C, 29.94: H, 3.30 : N, 13.30: S, 11.93. NMR(D2O) 1.44 (3H d,y=75), 1.46(6H,S), 4.48(1H, d of t j

=75, 5.5), 5.34(1H, d,y=5.5) 6.96ppm(1H ,S) .

Example 31

[3±(Z)]-3-[[(2-amino-4-thiazolyl)(methoxyimino)acetyl]amino]-4. 4- dimethyl- 2- oxo- l- azetidine sulfonic acid potassium salt.

A solution of N-hydroxybenzotriazole hydrate (50 mg) and (Z)-2-amino-α(methoxyimino)-4-thiazoleacetic acid (0.323 mmol) in 0.5 ml of dimethylformamide is treated with 67 mg of dicyclohexylcarbodiimide under argon at ambient temperature. The resulting mixture is stirred for 1 hour and (±)-3-amino-4,4-dimethyl-2-oxo-1-azetidine sulfonic acid (57 mg) is added as a solid followed by triethylamine dropwise (0.05 ml). The reaction mixture is stirred at ambient temperature for 16 hours. The dimethylformamide is removed under high vacuum at 30°C and the residue is suspended in 4 ml of acetone and filtered. The filter cake is washed with an additional 4 mL of acetone and potassium perfluorobutanesulfonate (85 mg) is added to the filtrate followed by ether. Trituration of the resulting gum with ether gives 40 mg of a dark solid which is chromatographed on a 70 ml HP-20AG column. Elution with water gives 20 mg of the title compound in fractions (5 ml) 16-40 after evaporation, trituration with 1:1 acetone-hexane and drying. Temp. 225°C, (decomposition).

Analysis calculated for CnHi4N506S2 "K: C, 31.80: H, 3.40: N, 16.86: S, 15.43,

Found: C, 29.47: H, 3.48: N, 14.98: S, 13.35.

Example 32

(3S-trans)-3-[[2-amino-4-thiazolyl)oxoacetyl]amino]-4-methyl-2-oxol-1-azetidine sulfonic acid potassium salt.

To a solution of diphenylphosphinyl chloride (1.85 g) in dry dimethylformamide (15 ml) cooled in an ice-methanol bath (-15 to -20°C) is added (2-amino-4-thiazolyl)glycylic acid triethylamine salt (2 .14 g). After stirring for 0.5 hour, a solution of (3S-trans)-3-amino-4-methyl-2-oxo-1-azetidinesulfonic acid (1.08 g) and triethylamine (1.92 ml) in dry dimethylformamide ( 5 ml) to the cold mixed anhydride solution and the reaction mixture is stirred at 5°C for 24 hours. Solvent is removed in vacuo, the remaining dark oil is dissolved in water and chromatographed on "Dowes 50 X2-400" resin (IC^ form, 200 ml). By elution with water (15 ml fractions), the crude product is collected in fractions 13-27 (3.37 g). Chromatography on HP-20 resin (200 ml) and elution with water (15 ml fractions) gives the desired product in fractions 18-26. Removal of water in vacuo gives the title compound as an amorphous powder.

Analysis calculated for C9HgN406S2K (372.42): C, 29.02: H, 2.44

N, 15.40: S, 17.22: K, 10.50 Found: C, 28.87: H, 2.62

N, 14.85: S, 15.09: K, 10.81

Example 33

[3S-[3a(Z),43]]-3-[[(2-amino-4-thiazolyl)[[2-(diphenyl-methoxy)-2-2oxoethoxy]imino]acetyl]amino]-2-methyl -4-oxo-1-azetidine sulfonic acid potassium salt.

By following the procedure of Example 25, but replacing (Z)-2-amino-α-(methoxyimino)-4-thiazoleacetic acid with (Z)-2-amino-α~[[2-(diphenylmethoxy)-2-oxoethoxy) imino]-4-thiazoleacetic acid and first treat (3S-cis)-3-amino-4-methyl-2-oxo-1-azetidinesulfonic acid with triethylamine, the title compound is obtained, melting point 155-160°C, split.

Example 34

[3S(R<*>)]-3-[[[[(4-amino-2,3-dioxo-1-piperazinyl)carbonyl]-amino]phenylacetyl]amino]-4-methyl-2-oxo-1 -azetidine sulfonic acid potassium salt.

[3S(R<*>)]-[4-[[[2-[(4-methyl-2-oxo-1-sulfo-3-azetidinyl)-amino]-2-oxo-1-phenylethyl]amino] carbonyl]-2,3-dioxo-1-piper-azinyl]-carbamic acid phenylmethyl ester potassium salt is hydrogenated using hydrogen gas and 10% palladium on charcoal as a catalyst to give the title compound, mp 165°C, dec.

Example 35

[3S(Z)]-3-[[(2-amino-4-thiazolyl)][(1-carboxy-1-methyl-ethoxy)imino]acetyl]amino]-2-oxo-1-azetidine sulfonic acid sodium salt ( 1:2).

[3S(Z)]-3-[[(2-amino-4-thiazolyl)[[2-(diphenylmethoxy)-1,1-dimethyl-2-oxoethoxy]imino]acetyl]amino]-2-oxo-1 -azetidine sulfone-

acid tetrabutylammonium salt (see Example 7) is deprotected using trifluoroacetic acid and anisole to give the title compound, m.p. 185°C, dec. after conversion to the disodium salt with aqueous sodium hydroxide and purification on HP-20.

Example 3 6

(trans,z)-3-[[(2-amino-4-thiazolyl)[(1-carboxy-1-methyloxy)-imino]acetyl]amino]-4-ethyl-2-oxo-1-azetidine sulfonic acid dipotassium salt . A) (trans,Z)-3-[[(2-amino-4-thiazolyl)[(-1-diphenylmethoxy-carbonyl-1-methylethoxy)imino]acetyl]amino]-4-ethyl-2-oxo-1 -azetidine sulfonic acid dipotassium salt.

(trans)-3-amino-4-ethyl-2-oxo-1-azetidine sulfonic acid

(0.55 g) and 335 g of triethylamine are dissolved in 50 ml of dry dimethylformamide. (Z)-2-amino-α-[(1-diphenylmethoxycarbonyl-1-methyl-ethoxy)imino]-4-thiazoleacetic acid (1.14 g) is added with stirring at =°C followed by 450 mg of hydroxybenzotriazole and then 0, 69 g of dicyclohexylcarbodiimide. After stirring for approx. 16 hours at 0°C, the flask is evacuated. Dry acetone (25 ml) is added to the solid with stirring. The mixture is filtered and 0.94 g of potassium perfluorobutanesulfonate is added to the filtrate followed by 100 ml of ether. After standing for 1 hour at 0°C, the solid is filtered off, washed with ether and dried in vacuo to give 1.58 g of the title compound. B) (trans,Z)-3-[[(2-amino-4-thiazolyl)[(1-carboxy-1-methyl-ethoxy)imino]acetyl]amino]-4-ethyl-2-oxo-1- azetidine sulfonic acid dipotassium salt.

To a suspension of 1.31 g of (trans,Z)-3-[[(2-amino-4-thiazolyl)[(1-diphenylmethoxycarbonyl-1-methylethoxy)imino]acetyl]-amino]-4-ethyl-2 -oxo-1-azetidinesulfonic acid dipotassium salt in 10 ml of anisole is added to 5 ml of trifluoroacetic acid during 10 minutes at -15°C. After stirring for 2 hours at -10°C, a clear solution is obtained. At -30°C, 80 ml of dry ether is added and the resulting precipitate is filtered off and then treated with 5 ml of water. The pH is then adjusted to 5.5 with potassium hydroxy(ln) at 0°C, and the mixture is filtered to remove unconverted starting material. The filtrate is chromatographed on HP-20 with water as eluent. Lyophilization gives 185 g of the title compound, melting point 160°C, split.

Example 37

[3S(Z)]-3-[[(2-amino-4-thiazolyl)[(4-hydroxy-4-oxobutoxy) iminolacetyl1aminol- 2- oxo- l- azetidine sulfonic acid potassium salt.

Deprotection from [3S(Z)]-3-[[(2-amino-4-thiazolyl)-[[4-(diphenylmethoxy)-4-oxobutoxy]imino]acetyl]amino]-2-oxo-1-azetidine sulfonic acid -potassium salt using trifluoroacetic acid and anisole to obtain the title compound of m.p.

>200°C.

Example 38

[3S-[3oc(Z),46]]-3-[[(2-amino-4-thiazolyl)(methoxy-imino)acetyl]-aminol-4-cyclohexyl-2-oxo-l-azetidine sulfonic acid potassium salt.

[ 3S-trans ]-3-amino-f 4 -cyclohexyl-2-oxo-1-azetidinesulfonic acid (0.25 g) is dissolved in 30 ml of dry dimethylformamide and 0.12 g of triethylamine with stirring. When a clear solution is obtained, add (Z)-2-amino-α-(methoxyimino)-4-thiazoleacetic acid (0.2 g), 0.16 g of hydroxybenzotriazole and 0.42 g of dicyclohexylcarbodiimide. Stirring is continued for 48 hours at ambient temperature. The precipitated urea is filtered off and the solvent is removed in vacuo. The residue is dissolved in 10 ml of acetone and 0.41 g of potassium perfluorobutanesulfonate is added. After adding 50 ml of ether, the title compound precipitates and it is filtered off. Column chromatography with HP-20 and water/acetone (9:1) as eluent gives 0.36 g of product, melting point 200-205°C (after lyophilization).

Example 39

[3S-[3a(Z),43]]-3-[[(2-amino-4-thiazolyl)[(1-carboxy-1-methyl-ethoxy)imino]acetyl]-amino]-4-cyclohexyl- 2-oxo-1-azetidine sulfonic acid dipotassium salt.

A) [3S-[3a(Z),43]]-3-[[(2-amino-4-thiazolyl)[(1-diphenylmethoxy-carbonyl-1-methylethoxy)imino]acetyl]amino]-4-cyclohexyl -2-oxo-1-acetidine sulfonic acid potassium salt. [3S-trans]-3-amino-4-cyclohexyl-2-oxo-1-azetidine sulfonic acid (0.2 g) is dissolved in 30 ml of dimethylformamide and 0.09 g of triethylamine with stirring. Hydroxybenzotriazole (0.12 g), 0.30 g (Z)-2-amino-α-[(1-diphenylmethoxycarbonyl-1-methylethoxy)-imino]-4-thiazoleacetic acid and 0.33 g dicyclohexylcarbodiimide are added and stirring at ambient temperature is continued for 12 hours. The precipitated urea is filtered off and the mother liquor is evaporated to dryness. The precipitated urea is filtered off and the mother liquor is evaporated to dryness. The remaining oil is dissolved in 5 ml of acetone, treated with 0.3 g of potassium perfluorobutane sulphonate and poured into 100 ml of ether with stirring. The title compound (0.61 g) is precipitated and filtered off. B) [3S-[3a(Z),43]]-3-[[(2-amino-4-thiazolyl)[(1-carboxyl-1methylethoxy)imino]acetyl]-amino]-4-cyclohexyl-2- oxo-1-azetidine sulphonate potassium salt.

[3S-[3a(Z),43]]-3-[[(2-amino-4-thiazolyl)[(1-diphenylmethoxy-carbonyl-1-methylethoxy)imino]acetyl]-amino]-4-cyclohexyl- 2-oxo-1-azetidine sulfonic acid potassium salt (0.61 g) is suspended in 6 ml of anisole, cooled to -15°C and 5 ml of trifluoroacetic acid is added dropwise with stirring. The temperature is maintained for one hour and then lowered to -30°C. About. 100 ml of dry ether is added at such a rate that the temperature does not exceed -10°C. The precipitated compound is filtered off and chromatographed using HP-20 resin and water/acetone, (9:1) as eluent to

give 0.3 g of the title compound, m.p. 110-120°C, cleaved.

(after lyophilization).

Example 40

(trans,Z)-3-[[(2-amino-4-thiazolyl)(methoxyimino)-acetyl]amino]4-ethyl- 2-oxo-1-azetidine sulfonic acid potassium salt.

By following the procedure of Example 36, but replacing (Z)-2-amino-α-[(1-diphenylmethoxycarbonyl-1-methylethoxy)imino]-4-thiazoleacetic acid with (Z)-2-amino-α(methoxyimino)- 4-thiazoleacetic acid, the title compound is obtained, melting point 190°C, distn.

Example 41

(±)-(trans,Z)-3-[[(2-amino-4-thiazolyl)(methoxyimino)-acetyl]-amino]-2-oxo-4-phenyl-1-azetidine sulfonic acid potassium salt.

A solution of N-hydroxybenzotriazole hydrate (52 mg) and (Z)-2-amino-α-(methoxyimino)-4-thiazoleacetic acid (69 mg) in dimethylformamide (0.3 ml) is treated with solid dicyclohexylcarbodiimide (70 mg) under argon at ambient temperature.The resulting mixture is stirred for 1 hour, (±-trans)-3-amino-2-oxo-4-phenyl-1-azetidine sulfonic acid (75 mg) is added as a solid, followed by triethylamine dropwise (0.05 The reaction mixture is stirred at ambient temperature for 23 hours. The dimethylformamide is removed under high vacuum at 30°C, and the residue is triturated with 2 ml of acetone and filtered. The filter cake is washed with additional acetone (two 3 ml portions) and potassium perfluorobutane sulfonate (86 mg) is added to the filtrate Dilution with 10 ml of ether gives a gummy solid which is triturated, washed with acetone and hexane to give 82 mg of the title compound as a solid after drying.

Analysis calculated for C15<H>i4N506S2'K: C, 40.26: H,3.16: N, 15.65: S, 14.33: K, 8.74

Found: C, 38.60: H, 3.19: N, 15.07

S, 13.87: K, 7.5.

in

Example 42

(cis,Z)-3-[[(2-amino-4thiazolyl)(methoxyimino)acetyl]amino]-2-oxo-4-phenyl-1-azetidine sulfonic acid potassium salt.

(cis)-2-oxo-4-phenyl-3-[(phenylacetyl)amino]-1-azetidine sulfonic acid potassium salt (560 mg) is dissolved in 5 ml of ethanol and hydrogenated with 110 mg of platinum oxide catalyst at one atmosphere. After one hour of stirring, the catalyst is filtered off

through a Millipore filter with "Celite": catalyst particles pass through the filter so that the filtrate becomes black. Ethanol is removed under reduced pressure and the residue is dissolved in 4 ml of dimethylformamide. N-hydroxy-benzotriazole monohydrate (169) mg), 221 mg (Z)-2-amino-α-(methoxyimino)-4-thiazoleacetic acid and 227 mg dicyclohexylcarbodiimide are added and the mixture is stirred for approx. 16 hours under nitrogen. The slurry is evaporated in vacuo and triturated with 15 ml of acetone. The resulting slurry is filtered through a Millipore filter with "Celite" and the filtrate is treated with 372 mg of potassium perfluorobutanesulfonate. On addition of 15 ml of ether, a gum separates. The liquid is removed and the rubber is washed with ether. The gum is dissolved in 5 ml of water and applied to 150 ml of HP-20 resin which is eluted with water. Fractions (30 mL each) 16-34 are combined and lyophilized to give 201 mg of the title compound as a solid.

Analysis calculated for Ci5Hi406N5S2K-1 1/2H20:

C, 36.73: H, 3.49: N, 14.28: S, 13.07: K, 7.97 Found: C, 36.65: H, 3.00: N, 13.99: S , 13.48: K, 8.30

Example 43

(±)-(cis,Z)-3-[[(amino-4-thiazolyl)(methoxyimino)acetyl)-amino]-2-oxo-4-(2-phenylethenyl)-1-azetidine sulfonic acid potassium salt.

A solution of 68 mg of (Z)-2-amino-α-(methoxyimino)-4-thiazoleacetic acid and 51 mg of N-hydroxybenzotriazole monohydrate in 2 ml of dimethylformamide is treated with 69 mg of dicyclohexylcarbodiimide. The mixture is stirred at room temperature for 30 minutes under nitrogen. (cis)-3-amino-2-oxo-4-(2-phenylethenyl)-1-azetidine sulfonic acid (90 mg) and 34 mg of triethylamine are added and the mixture is stirred for 20 hours under nitrogen. The slurry is evaporated in vacuo and triturated with 10 ml of acetone. The slurry is filtered and the filtrate is treated with 113 mg of potassium perfluorobutanesulfonate. Dilution with 30 ml of ether and filtration gives 169 mg of a solid product, which dissolves in a small amount of ac approx. 10% acetonitrile/water and applied to 34 ml HP-20 resin, eluted with 150 ml water, then 10% acetone/water. Fractions (15 mL each) 16-19 are combined and the solvent removed to give 110 mg of the title compound as a solid.

Analysis calculated for C17<H>16<0>6N5S2K<*>H20: C, 40.23: H, 3.57:

N, 13.80: S, 12.63: K, 7.70 Found: C, 40.03: H, 3.05: N, 13.61: S, 12.30: K, 7.56

Example 44

(cis)-3-[[(2-amino-4-thiazolyl)[[1-(diphenylmethoxycarbonyl)-1-methylethoxy]imino]acetyl]amino]-4-(methoxycarbonyl)-2-oxo-1-azetidine sulfonic acid- potassium salt.

A solution of N-hydroxybenzotriazole hydrate (34 mg) and

101 mg of 2-amino-α-[[1-(diphenylmethoxycarbonyl)-1-methylethoxy]-imino]-4-thiazoleacetic acid in 0.5 ml of dimethylformamide is treated with solid dicyclohexylcarbodiimide (45 mg) and the mixture is stirred under argon for 45 minutes ( ambient temperature). (cis)-3-amino-4-(methoxycarbonyl)-2-oxo-1-azetidine sulfonic acid (45 mg) is then added in solid form followed by triethylamine (0.03 ml) dropwise. The reaction mixture is stirred at ambient temperature for approx. 16 hours. The dimethylformamide is removed under high vacuum at 30°C and the residue is triturated with acetone. The above is treated with potassium perfluorobutanesulfonate (67 mg). Dilution with ether gives a solid which is washed with ether and dried in vacuo to give 93 mg of the title compound.

Example 45

(cis)-3-[[(2-amino-4-thiazolyl)[(1-carboxy-1-methylethoxy)imino]-acetyl]amino]-4-(methoxycarbonyl)-2-oxo-1-azetidine sulfonic acid dikal ium salt.

A slurry of (cis)-3-[[(2-amino-4-thiazolyl)[[(1-diphenylmethoxycarbonyl)-1-methylethoxy]imino]acetyl]amino]-4-(methoxycarbonyl)-2-oxo- 1-azetidine sulfonic acid potassium salt in 0.4 mg of anisole is stirred at -12°C under argon and 0.9 ml of cold (-10°C) trifluoroacetic acid is added. After 1.5 hours, 4 ml of ether and 2 ml of hexane are added and the resulting slurry is stirred for 15 minutes at -10°C and then for 15 minutes at ambient temperature. The solid is isolated by centrifugation and washed with ether. The pH of the suspension of this material in 0.5 ml of cold water is adjusted to 6 with 1N potassium hydroxide and then applied to a 30 ml column of HP-20AG. Elution with water gives 30 mg of the title compound after evaporation (acetonitrile added and evaporated twice).

Analysis calcd for C14<H>15K2N5O9S2: C, 31.15: H, 2.81: N, 12.98 Found: C, 29.08: H, 3.03: N, 12.19

Example 46

[3S-[3a(Z),46]]-3-[[(2-amino-4-thiazolyl)(methoxyimino)-acetyl]-amino]-4-ethynyl-2-oxo-1-azetidine sulfonic acid potassium salt.

(Z)-2-amino-α-(methoxyimino)-4-thiazolylacetic acid (100 mg), 85 mg of N-hydroxybenzotriazole and 113 mg of dicyclohexylcarbodiimide are added to a 10 ml flask. The flask is blown through with nitrogen and cooled in an ice-water bath. Then 0.6 ml of dimethylformamide is added and the mixture is stirred for 10 minutes, at which point a further 0.6 ml of dimethylformamide is added.

(S)-(trans)-3-amino-4-ethynyl-2-oxo-1-azetidine sulfonic acid (95

mg) is added as a solid with 1.0 ml of dimethylformamide and 56 µl of triethylamine. The cold bath is removed and the mixture is stirred for 22 hours. Acetone (3 ml) is added and any solids present are removed by filtration and washed with a further 4 ml of acetone. All solvents are removed in vacuo and the residue taken up in 5 ml of methanol, and 162 mg of potassium perfluorobutanesulfonate are added and dissolved. After standing, a solid settles and is isolated by centrifugation to give 68 mg of the title compound, mp >230°C.

Example 47

[3S(R<*>)]-3-[[(2-amino-4-thiazolyl)[[[3-[(2-furanylmethylene)amino]-2-oxo-1-imidazolidinyl]carbonyl]amino]acetyl ]amino]-2-oxo-1-azetidine sulfonic acid potassium salt.

By following the procedure from Example 1, but replacing aminothiazolacetic acid with (R)-2-amino-α-[[[3-(2-furanylmethylene)-amino]-2-oxo-1-imidazolidinyl]carbonyl]amino]-4 -thiazoleacetic acid, the title compound is obtained, melting point >250°C.

Biological activity.

The following method is used to determine the minimum inhibitory concentration (hereafter referred to as MIC) of the /?-lactams produced according to the invention.

The test organisms are grown for approx. 15-2o ml "AntibioticAssay broth" (Difco) by inoculating (in tubes) the liquid with a loopful of the organism from a "BHI" (Difco) agar slant. The inoculated tubes are incubated at 37°C for 18 to 20 hours. These cultures are believed to contain about 9 colony-forming units (hereafter CFU). per milliliters. The cultures are diluted 1:10 to give a final inoculum level of 1:10 4CFU; dilutions are carried out with K-lo liquid.

The compounds are dissolved in a suitable diluent

at a concentration of looo^ug/ml. Twofold dilution is done

with K-lo fluid resulting in a range from 100 to 0.5 µg/ml. 1.5 ml of each dilution is placed in individual square Petri dishes to which 13.5 ml of K-lo agar has been added. The final drug concentration in the agar varies from 100 ug/ml to 0.05 ug/ml. Organism growth control dishes containing only agar are prepared and inoculated before and after the test dishes. The organisms are applied to the agar surface in each dish with the "Denley Multi-point inoculator" (which delivers about 0.00 ml of each organism) resulting in a final inoculum level of 10 CFU on the agar surface.

The dishes are incubated at 37°C for 18 hours and the MIC is determined.

The MIC is the lowest concentration of a compound that inhibits organism growth.

""K-lo liquid is a yeast-meat liquid containing:

<**>K-lo agar

The tables that follow reproduce the results obtained when the β-lactams produced according to the invention are tested against different organisms. The number following each organism refers to the number of the organism in the collection of E.R. Squibb & Sons, Inc., Princeton, New Jersey. A line (-) in the table means that the tested compound did not show activity against the particular organism at loo^ug/ml.

The symbol "N.T." means: not tested.

Claims (2)

1. Analogy method in the preparation of therapeutic active 2-azetidinones of the general formula I where R 13 is hydrogen or C 1 -C 4 alkyl containing one carboxyl group or a C1~C4 alkyl or benzyl ester thereof, R 2 is hydrogen or C 1 -C 4 alkoxy, R 3 and R 4 are the same or different and are hydrogen or C 1 -C 4 alkyl, as well as salts thereof and stereoisomeric forms thereof, characterized by a) sulfonating a corresponding intermediate with a hydrogen atom in the 1-position with a pyridine-sulfur trioxide complex or an equivalent thereof according to usual conditions, or b) acylates a reduced intermediate in which R^ is hydrogen with an acyl group as defined by R^ above according to usual methods, and if desired transfers acid groups in salts, and/or if desired cleaves racemic mixtures into stereoisomeric forms. 2. Method according to claim 1 in the preparation of [3S-[3a(Z), 4(3]]-3[[(2-amino-4-thiazolyl)-[(1-carboxy-1-methyl-ethoxy)imino ]acetyl]amino]-4-methyl-2-oxo-1-azetidine sulfonic acid or salts or C 1 -C 4 alkyl or benzyl esters thereof, characterized by using correspondingly substituted starting materials.