New method for the direct electrophilic amination of aromatic compounds and its use in the annelation of the pyrimidine ring

Abstract

A method has been developed for the synthesis of aromatic amines by the amination of the corresponding aromatic compounds using sodium azide in PPA. A method for the synthesis of quinazolines and benzo [h]quinazolines using this reaction and the subsequent reaction of the intermediates with 1,3,5-triazines has been developed.In previous work [1, 2], we discovered a new reagent system for the electrophilic amination of aromatic compounds and shown its applicability for perimidines. In the present work, we have extended this method for the synthesis of other aromatic amines and shown its applicability in combination with 1,3,5-triazines for the annelation of the pyrimidine ring to aromatic compounds.As noted in our previous work [1, 2], the reaction of perimidines with a threefold excess of PPA at 80-90°C leads to the corresponding 6(7)-aminoperimidines in high yield. The PPA sample used containing 86% P 2 O 5 was obtained according to Uhlig [3].We might have assumed that this reagent system would be applicable for the amination of other aromatic compounds. Indeed, we showed that the reaction proceeds analogously with naphthalene to give 1-naphthylamine (2a) in 31% yield. The low yield is mostly a consequence of sublimation of naphthalene from the reaction mixture. NH 2 2) H 2 O 1a 2a 1) NaN 3 /PPA