N-alkenyl acylketene S, N-acetals from 2,3-dihydro-1,3-benzothiazoles and carboxylic anhydrides. X-Ray molecular structure of 2-(butyrylmethylene)N-(cyclohex-1-enyl)-2,3-dihydro-1,3-benzothiazole

Abstract

Depending on the reaction conditions or starting materials used, 2,3-dihydro-1,3-benzothiazoles 1 or their N-acyl derivatives 2 react with carboxylic anhydrides to yield the corresponding enamides 3 and/or N-alkenyl acylketene S,N-acetals 4. The structural assignments of these last compounds are based on spectroscopic data. X-Ray evidence for title compound 4c is also reported. A possible reaction pathway for formation of products 4 is suggested.