The Sinthesis and Chemical Properties of 11H-Cyclohepr[b]indeno[2,1-d]pyrrole

Abstract

The reaction of N-(3-indeny1)iminotributylphosphorane with 2-chlorotropone gave novel 11H-cyclohept[blindenol2,1-dlpyrrole, which was converted to the corresponding ketone and alcohol.The chemical properties of the three compounds were studied.~zaazulenes~) have received considerable interest, particularly in comparison with the chemistry of azulenes, and have played a major role in the advancement of our understanding of cyclic ~onjugation.~)The tetracyclic system containing the 1azaazulene nucleus, 11H-cyclohept[blindenol2,1-dlpyrrole (1) is of interest as a precursor of fully conjugated systems such as an anion (A) (1811 electron system) and a cation ( B ) (16n electron system).The synthesis of 1lH-indenol2,l-&lazulene ( 2 ) .which is a carbocyclic analogue of 1, has been accomplished previo~sly.~'~)Although the methodology constructing azulenes condensed with several ring systems has been r e ~o r t e d , ~) no convenient synthesis of l-azaazulenes condensed with various ring systems has been explored.Previously, the present authors have found that the reaction of 2-chlorotropone with N-vinyliminophosphoranes resulted in the formation of l-azaazulenes7) in a single step.This communication will describe a simple preparation and chemical properties of 1.Our synthetic strategy was at first to obtain N-(3in CH3CN: 306 (4.