The Behaviour of Vicinal Alkyl Aminothiophenecarboxylates in the Sandmeyer and Schiemann Reactions

Abstract

A b s t r a c t -The diazotization of vicinal alkyl aminothiophenecarboxylates h a s been studied.3-Amino compounds gave c l e a r diazanium s a l t s which yielded the expected halo d e r i v a t ~v e s in the Sandmeyer and Schiemann conditions.However, 2-amino compounds yielded self-coupling products.In o r d e r to study the Ullmann reaction f o r the preparation of thiophenic xantones, thioxantones and acridones, we were interested in the syntheses of the three possible i s o m e r i c vicinal halo-1-7 thioghenecarboxylic acids, e a s i e r than those described