Photolytic rearrangement of metronidazole to N-(2-hydroxyethyl)-5-methyl-1,2,4-oxadiazole-3-carboxamide. Crystal structure of its 4-nitrobenzoate derivative

Abstract

U.v. irradiation of metronidazole (1-hydroxyethyl-2-methyl-5-nitroimidazole) in oxygen-free aqueous solution leads to rearrangement via a labile intermediate to N-(2-hydroxyethyl)-5-methyl-1,2,4-oxadiazole-3-carboxamide. The structure has been verified by crystallographic assignment of a 4-nitrobenzoate derivative.