Tetrahedron

Selectivities in the formation of pyridines and pyrimidines by ammonia-induced cyclocondensations of vinamidiniums

SN Balasubrahmanyam, B Jeyashri, INN Namboothiri

Index: Natarajan Balasubrahmanyam; Jeyashri, Bommuswamy; Narayanan Namboothiri, Irishi N. Tetrahedron, 1994 , vol. 50, # 27 p. 8127 - 8142

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Citation Number: 17

Abstract

Arylvinamidines (2-, 3-or 4-aryl-4-(N, N-dimethyl) amino-1-azabuta-1, 3-dienes), generated from 1, 1, 5, 5-tetramethyl-2-or-3-phenyl-1, 5-diazapentadienium salts, cyclocondense orientation-specifically under two regioselections forming 1–4′+ 4-3′ and 1–2′+ 4-1′ bonds on exposure to ammonia. The initial cyclates aromatise eliminatively to give mixtures of diarylpyridines and arylpyrimidines. The 2-arylvinamidines do not participate as 2- ...