2,2':5',2''-Terthiophene-5-carboxylic Acid and 2,2':5',2''-Terthiophene-5,5''-dicarboxylic Acid

Article abstract of DOI:10.1021/jo00170a040

2,2':5',2''-Terthiophene-5-carboxylic acid was obtained in excellent yield by treating 2,2':5',2''-terthiophene with lithium diisopropylamide, followed by carboxylation of the lithium salt with solid carbon dioxide.The 5,5''-dicarboxylic acid was obtained similarly, when 2 equiv of base were used.Attempted syntheses of the monoacid, based on the oxidation of the corresponding aldehyde or the acetyl derivative, were unsuccessful.Both the monoacid and the 5,5'-diacid sensitized the hemolysis of human erythrocytes in the presence of ultraviolet light.