Novel Synthesis of 1,4-Dialkoxy-5,6,7,8-multisubstituted-2,3-dicyanonaphthalenes through Electron Transfer from Mg Metal and Efficient Development of New Naphthalocyanines

Abstract

Novel methods for efficient synthesis of 1,4-diamyloxy-5,6,7,8-multisubstituted-2,3-dicyanonaphthalenes were successfully developed, starting from easily available 2,3-dicyanohydroquinone as a common single compound through only three steps, the first dibromination of 2,3-dicyanohydroquinone, the second Mitsunobu dialkylation of 2,3-dicyano-5,6-diboromo-1,4-hydroquinone, and the last Diels-Alder-type of cycloaddition between 1,4-alkoxy-2,3-dicyano-5,6-diboromobenzenes and multisubstituted furans, followed by reductive deoxygenation with Mg turning. The obtained 1,4-diamyloxy-5,6,7,8-multisubstituted-2,3-dicyanonaphthalenes were easily transformed into the corresponding naphthalocyanines in 20-45% yields which showed their λmax at 867-892 nm.