Abstract: An object of the invention is to provide an industrially advantageous process capable of remarkably suppressing the generation of an undesirable by-product cepham compound to thereby efficiently produce a desired 2?-methyl-2?-[(1,2,3-triazol-1-yl)methyl]penam-3?-carboxylic acid ester. In the present invention, a diphenylmethyl 2?-bromomethyl-2?-methylpenam-3?-carboxylate (BMPB) is reacted with 1,2,3-triazole in a halogenated hydrocarbon solvent at ?5° C. or lower. The reaction in a halogenated hydrocarbon solvent at ?5° C. or less can remarkably suppress the generation of an undesirable by-product cepham compound, so that the desired diphenylmethyl 2?-methyl-2?-[(1,2,3-triazol-1-yl)methyl]penam-3?-carboxylate (TMPB) can be efficiently produced.

Abstract: The present invention provides anhydrous crystals of ?-lactam compound represented by the formula: The ?-lactam compound of the invention is produced by heating an aqueous solution of a salt of the ?-lactam compound and adjusting the pH of the aqueous solution to 3 or lower. The ?-lactam compound has excellent storage stability.

Abstract: The present invention provides anhydrous crystals of ?-lactam compound represented by the formula: The ?-lactam compound of the invention is produced by heating an aqueous solution of a salt of the ?-lactam compound and adjusting the pH of the aqueous solution to 3 or lower. The ?-lactam compound has excellent storage stability.

Abstract: The present invention provides novel 2?-methyl-2?-[(1,2,3-triazol-1-yl)methyl]penam-3?-carboxylic acid benzhydryl ester (TMPB)-acetone crystals for use in the production of 2?-methyl-2?-[(1,2,3-triazol-1-yl)methyl]penam-3?-carboxylic acid 1,1-dioxide benzhydryl ester (TAZB); a process for producing the TMPB-acetone crystals comprising the steps of (A) concentrating a TMPB-containing organic solvent solution, (B) dissolving the resulting concentrate in acetone, and (C) precipitating TMPB-acetone crystals from the acetone solution thus obtained; and a process for producing TAZB comprising the step of reacting the TMPB-acetone crystals with an oxidizing agent.

Abstract: An object of the invention is to provide an industrially advantageous process capable of remarkably suppressing the generation of an undesirable by-product cepham compound to thereby efficiently produce a desired 2?-methyl-2?-[(1,2,3-triazol-1-yl)methyl]penam-3?-carboxylic acid ester. In the present invention, a diphenylmethyl 2?-bromomethyl-2?-methylpenam-3?-carboxylate (BMPB) is reacted with 1,2,3-triazole in a halogenated hydrocarbon solvent at ?5° C. or lower. The reaction in a halogenated hydrocarbon solvent at ?5° C. or less can remarkably suppress the generation of an undesirable by-product cepham compound, so that the desired diphenylmethyl 2?-methyl-2?-[(1,2,3-triazol-1-yl)methyl]penam-3?-carboxylate (TMPB) can be efficiently produced.

Abstract: The present invention provides novel 2?-methyl-2?-[(1,2,3-triazol-1-yl)methyl]penam-3?-carboxylic acid benzhydryl ester (TMPB)-acetone crystals for use in the production of 2?-methyl-2?-[(1,2,3-triazol-1-yl)methyl]penam-3?-carboxylic acid 1,1-dioxide benzhydryl ester (TAZB); a process for producing the TMPB-acetone crystals comprising the steps of (A) concentrating a TMPB-containing organic solvent solution, (B) dissolving the resulting concentrate in acetone, and (C) precipitating TMPB-acetone crystals from the acetone solution thus obtained; and a process for producing TAZB comprising the step of reacting the TMPB-acetone crystals with an oxidizing agent.

Abstract: The crystal of the invention is crystal of diphenylmethyl 2-methyl-2-triazolylmethylpenam-3-carboxylate which is stable substantially without decomposition or degradation of properties even when left to stand at room temperature for 1 year. The crystal of the invention can be prepared by a process comprising the steps of concentrating a solution containing diphenylmethyl 2-methyl-2-triazolylmethylpenam-3-carboxylate represented by the formula (2) wherein Ph is a phenyl group, diluting the concentrate with acetic ester and mixing the diluted solution with hexane or a solvent mixture of hexane and acetic ester to crystallize the diphenylmethyl 2-methyl-2-triazolylmethylpenam-3-carboxylate.

Abstract: The crystal of the invention is crystal of diphenylmethyl 2-methyl-2-triazolylmethylpenam-3-carboxylate which is stable substantially without decomposition or degradation of properties even when left to stand at room temperature for 1 year.

Abstract: The crystal of the invention is the crystal of diphenylmethyl 2-methyl-2-triazolylmethylpenam-3-carboxylate 1,1-dioxide which is stable substantially without decomposition or degradation of properties even when left to stand at a temperature of 5 to 35° C. for a period of 1 year.

Abstract: A process for preparing halogenated &bgr;-lactam compounds, characterized in that a &bgr;-lactam amino compound of the formula (1) is reacted with nitrous acid or nitrite in a slurry dispersion state in water, under acid condition in the presence of halogen molecules, thereby obtaining a halogenated &bgr;-lactam compound of the formula (4) wherein n is an integer of 0 to 2; A is the formula (2) or (3); R1 and R2 are the same or different and are hydrogen atom, halogen atom, C1˜C3 alkyl group, C2˜C4 alkenyl group, C2˜C4 alkynyl group, nucleophilic group, or CH2R3; and R3 is halogen atom or nucleophilic group  wherein A is as defined above; X1 is hydrogen atom or halogen atom; and X2 is halogen atom.

Abstract: The invention provides a process for preparing a .beta.-lactam derivative represented by the formula ##STR1## the process comprising reacting a .beta.-lactam derivative represented by the following formula (II) and having a protected carboxyl group with a cresol; ##STR2## wherein R represents a benzyl group having an electron-donating group as a substituent on the phenyl ring, a diphenylmethyl group which may have an electron-donating group as a substituent on the phenyl ring or a tert-butyl group.

Abstract: A cephalosporin compound substituted by imidazolium ring in 3-position of cephem having the following formula (I), and pharmaceutically acceptable salt thereof, ##STR1## wherein R.sup.1 is an organic residue known in .beta.-lactam antibiotics, R.sup.2 is hydrogen atom or methoxy, n is 0 or 1, A is a nitrogen-containing group constituting imidazolium ring, is useful as an agent for preventing and treating bacterial infections.