Triethylamine → Ethyl 4-ethoxycarbonylmethylthio-5-formyl-6,7-dihydro-3-methylthiobenzo[c]thiophene-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a mixture of ethyl 4-chloro-5-formyl-6,7-dihydro-3-methylthiobenzo[c]thiophene-1-carboxylate (3.00 g), triethylamine (1.44 g) and pyridine (25 ml), ethyl thioglycolate (1.37 g) was added at 0° C., followed by stirring at 0° C. for 1.5 hours. The reaction mixture was concentrated under reduced pressure; the residue was poured over water and extracted with ethyl acetate. The organic layer was washed with 1 N hydrochloric acid and water in that order and dried (MgSO4), after which the solvent was distilled off. The residue was subjected to silica gel column chromatography and eluted with ethyl acetate-hexane (1:7 to 1:5, v/v) to yield ethyl 4-ethoxycarbonylmethylthio-5-formyl-6,7-dihydro-3-methylthiobenzo[c]thiophene-1-carboxylate (3.07 g, 81.0%), which was then recrystallized from ethyl acetate-hexane. Yellow prisms. Melting point 102-103° C.

Provenance & Evidence