Abstract: Described herein is 3-(pyrrolidinio)methyl-3-cephem derivative represented by the general formula: ##STR1## wherein Y stands for CH or nitrogen atom, R.sub.1 and R.sub.2 are the same or different, and represent a lower alkyl group, R.sub.3 denotes a hydroxy-substituted lower alkyl group, a lower alkyl group, or a carbamoyl group, and when Y stands for CH, R.sub.3 denotes a hydroxy-substituted lower alkyl group. The derivative is useful as antibacterial composition. Also described herein are process for the production of the derivative and antibacterial composition.

Abstract: 7-Carboxymethoxyphenylacetamido-3-cephem derivatives represented by the formula ##STR1## wherein R.sub.1 means hydroxy, C.sub.1 -C.sub.4 alkanoyloxy or C.sub.1 -C.sub.4 alkoxycarbonyloxy, R.sub.2 is hydrogen or methoxy, R.sub.3 denotes C.sub.1 -C.sub.4 alkanoyloxy, substituted or unsubstituted nitrogen-containing heterocyclic-thio or substituted or unsubstituted pyridinium with a proviso that, when R.sub.3 denotes the substituted or unsubstituted pyridinium, R.sub.3 forms an intramolecular salt with the carboxy at the 4-position of the cephem nucleus, and A is a group of the following formula: ##STR2## in which R.sub.4 and R.sub.5 are individually hydrogen or C.sub.1 -C.sub.4 alkyl, and their pharmaceutically acceptable salts, exhibit excellent anti-bacterial activities against Gram-negative bacteria, particularly, Pseud. aeruginosa, Kleb. pneumoniae, Ser. marcescens and the like.

Abstract: A novel 2-methylchromone derivative represented by the general formula: ##STR1## wherein R.sub.1 means a hydrogen atom or a lower alkanoyl group. The above derivative is a useful intermediate for the synthesis of cephem activities, which are also effective against infections of the urinary tract, etc. A preparation process of the above chromone derivative is also disclosed.

Abstract: A compound represented by the formula: ##STR1## wherein R.sub.1 is hydrogen or methoxy; R.sub.2 is hydrogen or hydroxy; R is ##STR2## wherein R.sub.3 and R.sub.4 are hydroxy or acyloxy, Y is oxygen, sulfur or >N-R.sub.5 wherein R.sub.5 is hydrogen or lower alkyl, and Z is sulfur or >N-R.sub.5 wherein R.sub.5 has the same meanings as defined above; and X is ##STR3## wherein R.sub.6 is acyloxy or nitrogen-containing heterocyclicthio which may have substituent(s), a pharmaceutically accpetable salt thereof, and a carboxylic ester thereof.This compound has improved antibacterial activity against Kleb. pneumoniae and Pseud. aeruginosa.

Abstract: Novel 7.alpha.-methoxycephalosporin derivatives, their pharmaceutically acceptable salts, process for the preparation thereof, and antibacterial drugs involving the derivative or salt. The derivatives or salts are effective against the Gram-positive bacteria and the Gram-negative bacteria.

Abstract: Cephem derivatives represented by the formula: ##STR1## wherein R.sub.1 represents a hydrogen atom or a hydroxyl group, R.sub.2 represents a lower alkyl group or a chloro-substituted lower alkyl group, and R.sub.3 represents a lower alkanoyloxy group or a nitrogen-containing heterocyclic thio group,and the pharmaceutically acceptable salts thereof. The cephem derivatives exhibit excellent antibacterial activity and are effective against Gram-positive and Gram-negative bacteria.

Abstract: Novel 7.alpha.-methoxycephalosporin derivatives, their pharmaceutically acceptable salts, process for the preparation thereof, and antibacterial drugs involving the derivative or salt. The derivatives or salts are effective against the Gram-positive bacteria and the Gram-negative bacteria.

Abstract: N-(Substituted chromone-3-carbonyl)phenylglycine derivatives. These derivatives are useful intermediates for cephem compounds which are excellent as antibacterial agents.

Abstract: New chromone derivatives having the formula: ##STR1## wherein A represents a hydrogen atom, a halogen atom or a hydroxyl group, and R.sub.1 represents a lower alkyl or a chloro-substituted lower alkyl group. The derivatives are useful intermediates for synthesis of cephem derivatives as antibacterial drugs.

Abstract: New cephalosporin derivatives represented by the general formula: ##STR1## wherein R.sub.1, R.sub.2, and R.sub.3 each represents hydroxy, acyloxy, and hydrogen provided that two or three of R.sub.1, R.sub.2, and R.sub.3 are not hydrogen at the same time, and their salts, and processes for the preparation thereof. The cephalosporin derivatives of the present invention are useful as antibacterial drugs.

Abstract: New cephalosporin derivatives having the general formula: ##STR1## wherein R.sub.1 and R.sub.2 each represents hydroxy or acyloxy and their salts, and processes for the production thereof. The cephalosporin derivatives of the present invention are useful as antibacterial drugs.

Abstract: Novel cephalosporin compounds of the general formula: ##STR1## wherein R.sub.1 represents a substituted or unsubstituted nitrogen-containing heterocyclic-thio group, R.sub.2 represents hydrogen or hydroxy, and R.sub.3, R.sub.4 and R.sub.5 each represents hydrogen, hydroxy or acyloxy, and their salts, and processes for the preparation thereof. The novel compounds and their salts have antibacterial activity.