Synthesis of 3-azaharman and other new azacarbolines of thepyridazino[4,5-b]indole type

Abstract

Starting from the indole-fused pyridazinone 3, a series of new pyridazino[4,5-b]indoles, functionalized at positions 1, 2, or 5 was prepared, including the two tetracyclic compounds 12 and 13, which represent new ring systems. Reductive dehalogenation of the chloro compound 8 gave a 3-aza isoster of the natural product, harman.