Abstract: An improved process for preparing 4-thia-2,6-diazabicyclo[3,2,0]hept-2-ene-7-ones such as methyl 3-phenoxy-4-thia-2,6-diazabicyclo[3,2,0]hept-2-ene-7-one-6-isopropenylacet ate which comprises extruding sulfur from dithiazeneazetidinones such as methyl 3-phenoxymethyl-4,5-dithia-2,7-diazabicyclo[4,2,0]-oct-2-ene-8-one-7-isopr openylacetate. The compounds obtained are useful intermediates in the preparation of certain 3-cephems.

Abstract: 3-(.beta.-aminoethylidene)-6-(.alpha.-hydroxyethyl)-7-oxo-4-oxaazabicyclo[3 .2.0]heptane-2-carboxylic acid having the structural formula: ##STR1## and the pharmaceutically acceptable salt, ester and amide derivatives thereof are disclosed to be useful as antibiotics. Also disclosed are processes for the preparation of such compounds; pharmaceutical compositions comprising such compounds; and methods of treatment comprising administering such compounds and compositions when an antibiotic effect is indicated.

Abstract: 3-(.beta.-aminoethylidene)-7-oxo-4-oxaazabicyclo [3.2.0]heptane-2-carboxylic acid and derivatives thereof having the structural formula: ##STR1## and the pharmaceutically acceptable salt, ester and amide derivatives thereof are disclosed to be useful as antibiotics. Also disclosed are processes for the preparation of such compounds; pharmaceutical compositions comprising such compounds; and methods of treatment comprising administering such compounds and compositions when an antibiotic effect is indicated.

Abstract: 3-(.beta.-Hydroxyethylidene)-6-(.alpha.-Hydroxyethyl)-7-oxo-4-oxaazabicyclo [3.2.0]heptane-2-carboxylic acid having the structural formula: ##STR1## and the pharmaceutically acceptable salt, ester and amide derivatives thereof are disclosed to be useful as antibiotics. Also disclosed are processes for the preparation of such compounds; pharmaceutical compositions comprising such compounds; and methods of treatment comprising administering such compounds and compositions when an antibiotic effect is indicated.

Abstract: The invention relates to novel azetidinones of the general formula: ##STR1## wherein R stands for lower alkyl, phenyl, phenyloxyloweralkyl, phenylloweralkyl, 2-thiophenemethyl, 5-tetrazolylmethyl, R.sup.3 O--and R.sup.3 S--, wherein R.sup.3 stands for lower alkyl, phenyl or phenylloweralkyl; R.sup.1 is hydrogen or a cleavable radical selected from lower alkyl; loweralkoxymethyl, 2,2,2-trichloroethyl, benzyl, p-halobenzyl, p-nitrobenzyl and p-methoxybenzyl, benzhydryl and trimethylsilyl; R.sup.2 is hydrogen or methoxy; X is SCl, Sbr or --OH in which case the C.sub.3 -sidechain is better represented as the amide RCONH-- group; Y is chloro or bromo; and ##STR2## may also be taken as phthalimido. These novel compounds possess antibacterial activity and are useful intermediates for the synthesis of modified penicillins and the analogues of penicillins.

Abstract: The invention relates to compounds of the formula: ##STR1## wherein R stands for lower alkyl, aryl, heteroaryl, benzyl, heteroarylloweralkyl, phenoxyloweralkyl, phenylthioloweralkyl, 4-amino-1-butyl and suitably protected derivatives, .alpha.-aminobenzyl and protected derivatives such as the carbamates (benzyl, trichloroethyl and methoxymethyl) and aldehyde and ketone adducts, .alpha.-hydroxybenzyl and protected derivatives, .alpha.-carboxybenzyl and protected derivatives, .alpha.-sulfobenzyl and protected derivatives, the radical R.sup.5 O--, R.sup.5 S--, or R.sup.5 R.sup.6 N--,wherein R.sup.5 and R.sup.6 may be the same or different and each be taken from the group lower alkyl, aryl, arylloweralkyl and heteroaryl and additionally, in the case of R.sup.5 R.sup.6 N--, R.sup.5 and/or R.sup.6 may be hydrogen;R.sup.

Abstract: The invention relates to compounds of the formula: ##STR1## wherein R stands forBenzyl,Phenoxymethyl,4-amino-4-carboxy-1-butyl,R.sup.3 o--, r.sup.3 s--, r.sup.3 r.sup.4 n-- whereinR.sup.3 is loweralkyl, aryl or arylloweralkyl,R.sup.4 is hydrogen or R.sup.3, andR.sup.2 is hydrogen or methoxy, andR.sup.1 is hydrogen or a cleavable radical such as--CH.sub.2 OCH.sub.3, loweralkyl, 2,2,2-trichloroethyl, benzyl, p-nitrobenzyl, benzhydryl, phenacyl or trimethylsilyl. The novel compounds are useful intermediates in the preparation of known penicillin and cephalosporin derivatives.

Abstract: The invention relates to compounds of the formula: ##STR1## wherein R stands for benzyl, phenoxymethyl, 4-amino-4-carboxy-1-butyl, R.sup.3 O--, R.sup.3 S--, R.sup.3 R.sup.4 N-- wherein R.sup.3 is loweralkyl, aryl or arylloweralkyl, R.sup.4 is hydrogen or R.sup.3, and OH when the radicals R.sup.3 O--, R.sup.3 S-- and R.sup.3 R.sup.4 N--are hydrolyzed; R.sup. 2 is hydrogen or methoxy, and R.sup.1 is hydrogen or a cleavable radical such as --CH.sub.2 OCH.sub.3, loweralkyl, 2,2,2-trichloroethyl, benzyl, p-nitrobenzyl, benzhydryl, phenoxyethyl or trimethylsilyl. The novel compounds are useful intermediates in the preparation of known penicillin and cephalosporin derivatives.