Synthesis of Azulene-Substituted Tetraarylpyrroles by Reaction of 1-Azulenyl Ketones with Benzoin and Ammonium Acetate

Abstract

Tetraarylpyrroles with a 1-azulenyl substituent were prepared by the reaction of 1-azulenyl ketones, which have various aryl-substituents at their α-position, with benzoin in the presence of ammonium acetate as a nitrogen source of the pyrrole ring. Optical property of the tetraarylpyrroles obtained by the reaction was clarified by UV/Vis spectroscopy and/or time-dependent density functional theory (TD-DFT) calculations.

Development of Heterocycle-Substituted and Fused Azulenes in the Last Decade (2010–2020)

“…The synthesis of tetraarylpyrroles 113 with a 1-azulenyl substituent has been accomplished by cyclization of benzoin with 1-azulenyl ketones 112 with various aryl groups at the α-position in the presence of ammonium acetate as the nitrogen source for the pyrrole ring ( Scheme 37 ) [ 56 ]. The yield of the reaction depends largely on the electronic properties of the aryl group substituted at the α-position of the ketones 112 .…”