R. Standridge, J. E. Swigor
Aug 1, 1993
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Journal
Journal of Labelled Compounds and Radiopharmaceuticals
Abstract
The title compound 9 was prepared by the route outlined in Scheme I. [14C]Thiourea (1) was condensed with ethyl 4-bromo-3-oxo-2-methoxyiminoacetate (2), providing ethyl 2-(2-amino-4-[2-14C]thiazolyl)-2-methoxyiminoacetate (3), as the pure Z-isomer. Saponification gave the amino acid 4; this was reacted with 1-hydroxybenzotriazole to give the activated ester 5. Condensation insitu with 7-amino-3-(1-methylpyrrolidinio) methyl-3-cephem-4-carboxylate (6) yielded the product as the pure sulfate salt (7). Treatment of 7 with base provided the zwitterion 8, isolated as the stable N-methyl-2-pyrrolidinone adduct. An aqueous solution of the adduct was converted to the crystalline title compound, [14C]Cefepime hydrochloride hydrate (9), with hydrochloric acid/acetone. Radiochemical purity was 99.0% and specific activity, 34.2 μCi/mg. Overall yield from [14C]thiourea was 18%.