| 主权项 |
1. A process of preparing benzo[1,2-b;4,5-b′]dithiophene-4,8-dicarboxylic acid or its 2,3-dihydro derivative, by
A) heating benzo[1,2-b;4,5-b′]dithiophene-4,4,8,8-tetracarboxylic acid, or an acid derivative thereof, in an organic solvent in the presence of a base and an oxidising agent, and adding an acid, to give benzo[1,2-b;4,5-b′]dithiophene-4,8-dicarboxylic acid, or B) heating benzo[1,2-b;4,5-b′]dithiophene-4,4,8,8-tetracarboxylic acid, or an acid derivative thereof, in a polar organic solvent in the presence of a base under exclusion of an oxidising agent, and adding an acid, to give 2,3-dihydrobenzo[1,2-b;4,5-b′]dithiophene-4,8-dicarboxylic acid. |
