Abstract: Provided is a process for diastereoselectively preparing compounds of the formula ##STR1## which includes the step of subjecting a compound of the formula ##STR2## to a salt whose anion is a nucleophilic base whose conjugate acid has a pKa in the range of between about -7 to about 14, or a silylated derivative of the salt; whereinR.sub.1 is said nucleophile;R is hydrogen, or protected amino,R.sub.2 is R.sub.4 as defined herein below;R.sub.3 is a leaving group; andR.sub.4 is hydrogen, C.sub.1 -C.sub.6 alkyl, or a group of the formula--CH.sub.2 --CH.sub.2 --R.sub.6whereinR.sub.6 is 2-furyl, naphthyl, phenyl, phenyl substituted with 1, 2 or 3 substituents selected from C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.6 alkylthio, nitro, halo, carboxy and amido; orR.sub.6 is a group of the formula--COOR.sub.7or--COSR.sub.7in whichR.sub.7 is selected from C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, benzyl, phenyl, or benzyl or phenyl substituted with 1, 2 or 3 substituents selected from C.sub.

Abstract: 1-Carbapenam-2-one-3-carboxylic acid and 1-carba-3-hydroxy-3-cephem-4-carboxylic acid and esters thereof are provided by a process comprising a rhodium C.sub.2 -C.sub.10 carboxylate catalyzed cyclization of an ester of a 4-(1-alkoxy- or 1-substituted alkoxy)-2-oxo-4-azetidinyl)-.beta.-ketobutyric acid and an ester of a 5-(1-alkoxy- or 1-substituted alkoxy-2-oxo-4-azetidinyl)-.alpha.-diazo-.beta.-ketovaleric acid respectively. The process is carried out in an inert organic solvent at a temperature between about 15.degree. C. and about 85.degree. C. The 1-carba bicyclic .beta.-lactams are intermediates for preparing antibiotics.

Abstract: 1-Carbapenam-2-one-3-carboxylic acid and 1-carba-3-hydroxy-3-cephem-4-carboxylic acid and esters thereof are provided by a process comprising a rhodium C.sub.2 -C.sub.10 carboxylate catalyzed cyclization of an ester of a 4-(1-alkoxy- or 1-substituted alkxoy)-2-oxo-4-azetidinyl)-.alpha.-diazo-.beta.-ketobutyric acid and an ester of a 5-(1-alkoxy- or 1-substituted alkoxy-2-oxo-4-azetidinyl)-.alpha.-diazo-.beta.-ketovaleric acid respectively. The process is carried out in an inert organic solvent at a temperature between about 15.degree. C. and about 85.degree.0 C. The 1-carba bicyclic .beta.-lactams are intermediates for preparing antibiotics.

Abstract: Monocyclic .beta.-lactam compounds represented by the formula ##STR1## wherein R.sub.1 is H, NH.sub.2, acylamino, C.sub.1 -C.sub.4 alkyl, etc.; R.sub.2 is e.g. C.sub.1 -C.sub.4 alkyl, hydroxyalkyl, aminoalkyl, carboxy, esterified carboxy, esterified carboxyalkyl, or carboxyalkyl; and R.sub.3 is hydrogen, benzyl, substituted benzyl, pivaloyl, --SO.sub.3 M, or --P(C.dbd.O)(OM')2; are obtained by the cyclization of an O-substituted hydroxamate of a .beta.-substituted alkylcarboxylic acid. For example, .alpha.-ethylmalic acid monobenzyl ester is reacted with O-benzylhydroxylamine to form the O-benzylhydroxamate of the free carboxy group, and the hydroxamate is cyclized with diethyl diazodicarboxylate and triphenylphosphine to form the .beta.-lactam of the above formula wherein R.sub.1 is ethyl, R.sub.2 is benzyloxycarbonyl and R.sub.3 is benzyl. The .beta.-lactam compounds are useful intermediates for preparing .beta.-lactamase inhibitors and monocyclic .beta.-lactam antibiotics and, when R.sub.3 is --SO.sub.

Abstract: A stereoselective process for chiral intermediates to 1-carbapenem and 1-carbacephalosporins is provided comprising the use of an N-acyl-(4R)-substituted-1,3-thiazolidine-2-thione as a chiral auxiliary in boron enolate mediated aldol condensation with a protected-.beta.-keto ester aldehyde. E.g., benzyl 3,3-(ethylenedioxy)-4-formylbutyrate is condensed with the boron enolate formed with n-butyryl (4R)-methoxycarbonyl-1,3-thiazolidine-2-thione to provide benzyl 3,3-ethylenedioxy-(5R)-hydroxy-6-[(4R)-methoxycarbonyl-1,3-thiazolidine-2- thione-3-ylcarbonyl]octanoate. Displacement of the thiazolidine-2-thione chiral auxiliary moiety with an O-alkyl, O-acyl or O-aralkyl hydroxyamine provides the corresponding chiral intermediate as the hydroxamate.

Abstract: The invention provides azetidinones of the formula ##STR1## where R.sub.4 is hydrogen, amino or protected amino; R.sup.0 is H when R.sub.4 is amino or protected amino, or C.sub.1 -C.sub.4 alkyl when R.sub.4 is H; R.sub.1 is H, CH.sub.3, --CH.sub.2 --.sub.n Y where Y is OH, protected OH, --CH.sub.2 OH, protected --CH.sub.2 OH, halogen, COOH or protected COOH; n is 1 or 2; --CH.sub.2 --C(O)SR.sub.1 ' where R.sub.1 ' is e.g., C.sub.1 -C.sub.4 alkyl; R.sub.2 is H or protecting group and R.sub.3 is e.g., alkyl or phenyl. The azetidinones obtained are useful intermediates to carbapenems and carbacephems and monocyclic antibacterials, e.g., .alpha.-(dialkylphosphono)-[[3.beta.-[2-(2-aminothiazol-4-yl)-2-(syn)metho xyiminoacetylamino]azetidin-2-one-1-yl]]acetic acid and pharmaceutically acceptable salts thereof.

Abstract: A process for 4-halomethylazetidin-2-ones is provided which comprises mixing in an inert solvent a positive halogen reagent in the presence of a weak base with a .beta.,.gamma.-unsaturated O-acylhydroxamate of the formula ##STR1## wherein R is protected amino, lower alkyl or phenyl substituted lower alkyl, R.sub.2 is a substituent such as lower alkyl which may be substituted by formyl, hydroxy, halogen, etc., and R.sub.1 is alkoxy, benzyloxy, etc. When R is a protected amino group, the process provides cis-4-halomethylazetidin-2-ones, while when R is alkyl or phenylalkyl, the trans isomer is obtained. The 4-halomethylazetidinones are useful intermediates for known antibiotic compounds.

Abstract: A stereoselective process for chiral intermediates to 1-carbapenum and 1-carbacephalosporins is provided comprising the use of an N-acyl-(4R)-substituted-1,3-thiazolidine-2-thione as a chiral auxiliary in boron enolate mediated aldol condensation with a protected-.beta.-keto ester aldehyde. E.g., benzyl 3,3-(ethylenedioxy)-4-formylbutyrate is condensed with the boron enolate formed with n-butyryl (4R)-methoxycarbonyl-1,3-thiazolidine-2-thione to provide benzyl 3,3-ethylenedioxy-(5R)-hydroxy-6-[(4R)-methoxycarbonyl-1,3-thiazolidine-2- thione-3-ylcarbonyl]octanoate. Displacement of the thiazolidine-2-thione chiral auxiliary moiety with an O-alkyl, O-acyl or O-aralkyl hydroxyamine provides the corresponding chiral intermediate as the hydroxamate.

Abstract: Process for N-acyloxy or sulfooxy 2-azetidinones comprising O-acylation of a .beta.-hydroxy or .beta.-halo hydroxamic acid, and cyclizing the O-acylhydroxamate with TPP-CCl.sub.4 -TEA or with TPP-dialkylazodicarboxylate to the N-acyloxy-2-azetidinone. Solvolysis of the acyl group provides an N-hydroxy-2-azetidinone. e.g., N-Cbz-L-serine is converted to the O-acetyl hydroxamate, cyclized and solvolyzed to N-hydroxy-3-(Cbz-amino)-2-azetidinone. The N-hydroxy-2-azetidinones are useful intermediates to monocyclic .beta.-lactam antibiotics and .beta.-lactamase inhibitors.

Abstract: N-Mono or N-disubstituted methyl-2-azetidinones are provided via cyclization of .beta.-hydroxy or .beta.-halo substituted acid sec-amides wherein the amide nitrogen is substituted with a mono- or di-substituted methyl group having activating substituents. Cyclization of .beta.-hydroxy acid amides is mediated by triphenylphosphine-dialkylazodicarboxylate while cyclization of .beta.-halo acid amides is mediated by strong bases e.g. lithium dialkylamides. E.g. Diethyl amino-protected L-serylaminomalonate is cyclized with 200 mole % TPP-diisopropylazodicarboxylate to N-(diethoxycarbonylmethyl)-3-protected-amino-2-azetidinone. The 2-azetidinones provided are useful intermediates.

Abstract: Process for N-acyloxy or sulfooxy 2-azetidinones comprising O-acylation of a .beta.-hydroxy or .beta.-halo hydroxamic acid, and cyclizing the O-acylhydroxamate with TPP-CCl.sub.4 -TEA or with TPP-dialkylazodicarboxylate to the N-acyloxy-2-azetidinone. Solvolysis of the acyl group provides an N-hydroxy-2-azetidinone. E.g., N-Cbz-L-serine is converted to the O-acetyl hydroxamate, cyclized and solvolyzed to N-hydroxy-3-(Cbz-amino)-2-azetidinone. The N-hydroxy-2-azetidinones are useful intermediates to monocyclic .beta.-lactam antibiotics and .beta.-lactamase inhibitors.