Acetic Anhydride → 4',5'-dihydrospiro[benzo[b]thiophene-2(3H), 3'(2'H)-furan]3,2'-dione

Participants

Reaction Conditions

Reaction Steps

A mixture of 15.5 g of α-[(2-carboxyphenyl)thio]-γ-butyrolactone, 100 ml of acetic anhydride and 20 ml of triethylamine is stirred at 140° C. for 3 hours, at the end of which time the solvent is distilled off. To the residue is added ice-water and the resultant precipitate is recovered by filtration and recrystallized from ethanol. By the above procedure there is obtained 9.4 g of 4',5'-dihydrospiro[benzo[b]thiophene-2(3H), 3'(2'H)-furan]3,2'-dione as pale-yellow platelets melting at 125°-127° C.

Provenance & Evidence