Thioglycolic Acid → 3-methylbenzo[b]thiophene-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

Potassium hydroxide (12.5 g) was dissolved in water (105 ml) in a glass pressure bottle cooled in an ice bath. Then under a blanket of nitrogen, thioglycolic acid (7 ml) was added to the glass pressure bottle, to produce a reaction mixture. 2'-chloroacetophenone (12 g, 97%, 0.075 mol) and TBAB (0.5 g) were then added to the reaction mixture. The glass pressure bottle was then sealed and heated to 253° F. for 6 hours at 18 psi. The reaction was shut down and left overnight. Heating was then resumed at 270° F. at 30 psi for six hours and then cooled to ambient temperature. After the bottle was opened, the reaction mixture was washed with ether to remove organics, and acidified with hydrochloric acid to give 3.9 g of crude 3-methyl 2-benzo[b]thiophenecarboxylic acid (27% yield, mp>200° C.).

Provenance & Evidence