N-(7-acylamidoceph-3-em-3-ylmethyl)-pyridinium-4-carboxylate, antibiot

摘要

Preparation of Cephalosporin CA derivatives (N-(7-acylamidoceph-3-em-3-ylmethyl) pyridinium-4-carboxylate) as follows:- (a) 7-acylamidocephalosporanic acid is reacted with pyridine in the presence of thiocyanate or iodide-ions to yield the crude hydrothiocyanate or the hydroiodide of N-(7-acylamidoceph-3-em-3-ylmethyl)pyridinium-4-carboxylate. (b) The crude hydrothiocyanate or the hydroiodide is converted to the betaine form which is reacted with a base, the betaine is recovered in an aqueous phase, and the thiocyanate or hydroiodide impurities in an organic phase. (c) The aqueous phase is further purified by passage through ion-exchangers. (d) The purified aqueous phase is reacted with nitric acid to form an insoluble acid addition salt. (e) This salt is separated from the mother liquor and converted to the betaine-form by reaction with a base. Antibiotic.