... During a study of the chemistry of indenothiophenes, 4H-indeno[ 1,2-b]thiophene-4-carboxylic acid (2) was pre- pared in 39 ... 2888 J. Org. ... Hydrolysis followed by extraction of organic extra& with Na2C08 and acidification gave a brown solid precipitate (0.8 g) which was extracted ...