Process for producing 7-(substituted)amino-3-substituted thiomethyl cephem carboxylic acids

Claim 1

A process for producing a 7-(substituted)-amino-3-substituted thiomethyl cephem carboxylic acid represented by the formula: ##STR17## wherein R 1 is a hydrogen atom; R 2 is an amino group; and R 8 is a moiety of a compound of the formula HSR 8 wherein SR 8 is a conventional 3-position cephalosporin thio substituent wherein R 8 is an unsubstituted or substituted ring carbon containing heterocyclic group, or said compound (I) in which the carboxyl group is protected by a conventional cephalosporin carboxy protecting group or a conventional cephalosporin salt thereof, which comprises reacting a cephalosporanic acid represented by the formula: ##STR18## wherein R 1 and R 2 have the same meanings as defined above; X is carboxylic acyloxy or carbamoyloxy group or one of said groups substituted by a conventional cephalosporin substituent; >Y is >S or>S→O; or said compound (II) in which the carboxyl group is protected by a conventional cephalosporin carboxy protective group or a conventional cephalosporin salt thereof, with a thiol compound represented by the formula: R.sup.8 --SH (III) wherein R 8 has the same meaning as defined above, or a salt thereof with a compound forming a conventional cephalosporin salt, in a non-aqueous organic solvent at a temperature of -20° to 80° C. in the presence of boron trifluoride or a complex compound thereof which acts as boron trifluoride, the boron and the fluorine bonded to boron in said complex compound being present as BF 3 .