Tautomerism in 2-trichloro- and 2-trifluoro-acetamidothiazoles

Abstract

Series of new 4- and 5-substituted thiazoles with acetamido-, mono-, di-, and tri-chloroacetamido-, and trifluoroacetamido-groups at position 2 have been prepared. Amide-acylimine tautomerism in these compounds has been investigated by comparing their i.r. and u.v. spectra in carbon tetrachloride and in acetonitrile with those of related 2-N-methylacetamido- and 3-methyl-2-acetylimino-thiazoles. The trichloro- and trifluoro-acetamides exhibit tautomerism in both solvents; the acylimine-forms are most stable with the trifluoro-compounds in the more polar solvent.