General synthesis of dibenzotetrathiafulvalenes

Abstract

A wide variety of dibenzotetrathiafulvalenes (1) were synthesized starting from anthranilic acids. Aprotic diazotization of anthranilic acids by isopentyl nitrite in the presence of carbon disulphide and isopentyl alcohol in boiling 1,2-dichloroethane gave 2-isopentoxy-1,3-benzodithioles (2). Compounds (2) were converted into 1,3-benzodithiolylium tetrafluoroborates (3) by treatment with tetrafluoroboric acid. Treatment of the salts (3) with base afforded tetrathiafulvalenes (1).