An Efficient Preparation of 1,2-Bis(Dipyrrin-9-Ylene)-Ethane, the First Fully Conjugated b-Homobilin

Abstract

1,2-Bis(dipyrrin-9-ylene)-ethane 1, the first fully conjugated b-homobilin, was synthesized in two steps with excellent yield by first condensing 1,2-bispyrrylethane 3 with 2 molecular 5-formylpyrrole 4, followed by dehydration of the result 1,2-Bis(dipyrrin-9-yl)-ethane 2 with DDQ in dichloromethane. The chemical and spectroscopic properties of this novel chromophoric system are discussed.