A new ring transformation: conversion of 6-p-chlorophenyl-3-methyl-5-nitrosoimidazo[2,1-b]thiazole into 8-p-chlorophenyl-8-hydroxy-5-methyl-3-oxo-1,2,4-oxadiazolo[3,4-c][1,4-]thiazine by the action of mineral acids

Abstract

6-p-Chlorophenyl-3-methyl-5-nitrosoimidazo[2;1-b]thiazole 1 by treatment with dilute hydrochloric acid in dioxane at room temperature gave 8-p-chlorophenyl-8-hydroxy-5-methyl-3-oxo-1,2,4-oxadiazolo[3,4-c][1,4]thiazine 2, containing a new condensed ring system the molecular structure of which was ascertained by physical methods (¹H and ¹³C NMR, electron impact-mass and IR spectra, and XRD).