Abstract: Disclosed are compounds of the general formula: ##STR1## wherein R.sub.1 is amino, an acylated amino or a protected amino group, X is hydrogen or methoxy, and R' is hydrogen, R or R.sup.4 wherein R is an organic residue attached to the azetidine ring through a carbon atom therein and R.sub.4 is azido, a halogen, an amino group which may optionally be acylated or a group of the formula ##STR2## wherein R.sub.5 is an organic residue and n is 0, 1 or 2, and pharmeceutically acceptable salts and esters thereof.The compounds have antimicrobial and/or .beta.-lactamase-inhibitory activity and are of value as drugs for human beings and domesticated animals.

Abstract: Disclosed are compounds of the general formula: ##STR1## wherein R.sub.1 is amino, an acylated amino or a protected amino group, X is hydrogen or methoxy, and R' is hydrogen, R or R.sup.4 where R is an organic residue attached to the azetidine ring through a carbon atom therein and R.sub.4 is azido, a halogen, an amino group which may optionally be acylated or a group of the formula ##STR2## wherein R.sub.5 is an organic residue and n is 0, 1 or 2, and pharmaceutically acceptable salts and esters thereof.The compounds have antimicrobial and/or .beta.-lactamase-inhibitory activity and are of value as drugs for human beings and domesticated animals.

Abstract: Disclosed are compounds of the general formula: ##STR1## wherein R.sub.1 is amino, an acylated amino or a protected amino group, X is hydrogen or methoxy, and R' is hydrogen, R or R.sup.4 wherein R is an organic residue attached to the azetidine ring through a carbon atom therein and R.sub.4 is azido, a halogen, an amino group which may optionally be acylated or a group of the formula ##STR2## wherein R.sub.5 is an organic residue and n is 0, 1 or 2, and pharmaceutically acceptable salts and esters thereof.The compounds have antimicrobial and/or .beta.-lactamase-inhibitory activity and are of value as drugs for human beings and domesticated animals.

Abstract: Novel 1-sulfo-2-oxoazetidine derivatives and their production and use.These 1-sulfo-2-oxoazetidine derivatives exhibit excellent antimicrobial activity against gram-positive and gram-negative bacteria, and .beta.-lactamase inhibitory activity, thus being of value as a prophylactic or therapeutic agent for infectious diseases in mammals.

Abstract: Compounds having one or two substituents at the 3-position, represented by the general formula ##STR1## wherein R.sub.1 is an optionally acylated or protected amino group and X is hydrogen atom or methoxy group, or a pharmaceutically acceptable salt thereof; when used either alone or in combination with a .beta.-lactam antibiotic, show excellent .beta.-lactamase inhibitory activity and can be used as drugs for use in humans and domestic animals.

Abstract: 4-Cyano-2-azetidinone derivatives represented by the formula ##STR1## wherein R.sup.1 is an amino group which may be acylated or protected, X is a hydrogen atom or a methoxy group and W is a hydrogen atom or a sulfo group, and methods of producing the same, for example, as represented by ##STR2## wherein R.sup.2 is an acylated or protected amino group, Y is a halogen atom or a group having the formula --OCOR.sup.3, --SCOR.sup.3 or --S(O).sub.n --R.sup.3 (R.sup.3 being a hydrocarbyl group and n an integer 1 or 2), R.sup.4 is an amino group which may be acylated or protected and X is as defined above. Compounds [I] are useful as advantageous intermediates for the synthesis of optically active 4-substituted-2-azetidinone derivatives, and, when W=SO.sub.3 H, [I] are also useful as antimicrobial agents and as beta-lactamase inhibitors.

Abstract: Disclosed are compounds of the general formula: ##STR1## wherein R.sub.1 is amino, an acylated amino or a protected amino group, X is hydrogen or methoxy, and R' is hydrogen, R or R.sup.4 wherein R is an organic residue attached to the azetidine ring through a carbon atom therein and R.sub.4 is azido, a halogen, an amino group which may optionally be acylated or a group of the formula --OR.sub.5, ##STR2## or --S--S--R.sub.5 wherein R.sub.5 is an organic residue and n is 0, 1 or 2, and pharmaceutically acceptable salts and esters thereof.The compounds have antimicrobial and/or .beta.-lactamase-inhibitory activity and are of value as drugs for human beings and domesticated animals.

Abstract: Compounds of the formula ##STR1## are useful as intermediates in preparing 1-sulfo-2-oxoazetidine compounds having the carbamoyloxymethyl group at the 4-position. The final product compounds have antimicrobial and/or .beta.-lactamase-inhibitory activity and are of value as drugs for human beings and domesticated animals.

Abstract: Disclosed are compounds of the general formula: ##STR1## wherein R.sub.1 is amino, an acylated amino or a protected amino group, X is hydrogen or methoxy, and R' is hydrogen, R or R.sup.4 wherein R is an organic residue attached to the azetidine ring through a carbon atom therein and R.sub.4 is azido, a halogen, an amino group which may optionally be acylated or a group of the formula --OR.sub.5, ##STR2## or --S--S--R.sub.5 wherein R.sub.5 is an organic residue and n is 0, 1 or 2, and pharmaceutically acceptable salts and esters thereof.The compounds have antimicrobial and/or .beta.-lactamase-inhibitory activity and are of value as drugs for human beings and domesticated animals.

Abstract: Disclosed are compounds of the general formula: ##STR1## wherein R.sup.1 is a hydrogen atom or a lower alkyl group and R.sup.2 is a hydrogen atom or an ester residue, said derivative having the (3S,4S)-configuration; and pharmaceutically acceptable salts and esters thereof.The compounds have antimicrobial and/or .beta.-lactamase-inhibitory activity and are of value as drugs for human beings and domesticated animals.

Abstract: 4-Cyano-2-azetidinone derivatives represented by the formula ##STR1## wherein R.sup.1 is an amino group which may be acylated or protected, X is a hydrogen atom or a methoxy group and W is a hydrogen atom or a sulfo group, and methods of producing the same, for example, as represented by ##STR2## wherein R.sup.2 is an acylated or protected amino group, Y is a halogen atom or a group having the formula --OCOR.sup.3, --SCOR.sup.3 or --S(O).sub.n --R.sup.3 (R.sup.3 being a hydrocarbyl group and n an integer 1 or 2), R.sup.4 is an amino group which may be acylated or protected and X is as defined above. Compounds [I] are useful as advantageous intermediates for the synthesis of optically active 4-substituted-2-azetidinone derivatives, and, when W=SO.sub.3 H, [I] are also useful as antimicrobial agents and as beta-lactamase inhibitors.

Abstract: Disclosed are compounds of the general formula: ##STR1## wherein R.sub.1 is amino, an acylated amino or a protected amino group, X is hydrogen or methoxy, and R' is hydrogen, R or R.sup.4 wherein R is an organic residue attached to the azetidine ring through a carbon atom therein and R.sub.4 is azido, a halogen, an amino group which may optionally be acylated or a group of the formula --OR.sub.5, ##STR2## or --S--S--R.sub.5 wherein R.sub.5 is an organic residue and n is 0, 1 or 2, and pharmaceutically acceptable salts and esters thereof.The compounds have antimicrobial and/or .beta.-lactamase-inhibitory activity and are of value as drugs for human beings and domesticated animals.

Abstract: Novel 3-methoxy-2-oxoazetidine derivatives, which are shown by the following formula ##STR1## wherein R.sub.1 is amino, acylated amino or protected amino, are of value as intermediates for the synthesis of useful compounds represented by the formula ##STR2## wherein R.sub.1 has the same meaning as defined above, as drugs in the treatment of bacterial infections.

Abstract: Novel cephem compounds having a group of the formula at the 3-position thereof: ##STR1## wherein X represents oxygen, sulfur or imino, which may be substituted; and B represents hydrogen or a hydroxyl, amino, mercapto or hydrocarbon group, which groups may be substituted, can be prepared by reacting a 3-formylcephem compound with a hydrazine compound of the formula: ##STR2## wherein the symbols have the same meanings as above, and subjecting the thus obtained compound to an oxidative ring-closure reaction. The objective compounds are found to have a broad antimicrobial spectrum and, in particular, are effective against gram-negative bacteria including Escherichia Coli, Klebsiella pneumoniae, Proteus vulgaris, Proteus mirabilis, Proteus rettgerii, as well as gram positive ones, and have low-toxity. Thus, these compounds may be used for antimicrobial agents in therapeutical purpose.