Hydrochloric Acid → Dimethyl 4-chloro-3-hydroxybenzo[b]thiophene-2,5-dicarboxylate

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Reaction Steps

Dimethyl 2,4-dichloroisophthaloate (11.95 g) and methyl thioglycolate (7.23 g) was dissolved in N,N-dimethylformamide, and lithium hydroxide monohydrate (3.81 g) added. The mixture was stirred at ambient temperature for 2 days, diluted with water and brought to pH 1 with hydrochloric acid. The solid was filtered, washed with boiling cyclohexane and dried by azeotropic removal of toluene to give dimethyl 4-chloro-3-hydroxybenzo[b]thiophene-2,5-dicarboxylate (13.44 g) as a beige solid, m.p. 127°-131° C.

Provenance & Evidence