Chlorine displacement of heterocyclic halides by enolate-oxygen: synthesis of 1,3-oxathiol-2-imines from 5-chloro-1,2,4-thiadiazol-3(2H)-ones and active methylene ketones and esters

Abstract

1,3-Oxathiol-2-imines 4–8 are conveniently prepared from 5-chloro-1,2,4-thiadiazol-3(2H)-one 3 and pentane-2,4-dione, methyl acetoacetate, dimethyl malonate and cyclohexane-1,3-diones, while the normal substitution product 9 is obtained from the thiadiazole 3 and Meldrum's acid.