Dissymmetry of certain substituted dipyridotetraazapentalenes

DE Pereira, GL Clauson, NJ Leonard

Index: Pereira, David E.; Clauson, Gary L.; Leonard, Nelson J. Tetrahedron, 1987 , vol. 43, # 21 p. 4931 - 4946

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Citation Number: 8

Abstract

In a two-step synthesis from starting amines, a series of compounds has been prepared in which steric crowding (lb, c, d, f) was introduced into the “bay region” of pyrido [1 “, 2”: 1 ', 2'] imidazo [4 ', 5': 4, 5] imidazo [1, 2-a] pyridine (1a). This forces the tetracyclic ring system into non-planarity. Two hexaheterohelicencs 2a and b were prepared that incorporate the 1, 3, 4, 6-tetraazapentalene ring system and provide molecular crowding in the “bay region” due ...