反应详情

Ethyl 4-ethoxycarbonylmethylthio-5-formyl-6,7-dihydro-3-methylthiobenzo[c]thiophene-1-carboxylate (0.30 g) was dissolved in acetic anhydride (10 ml) and refluxed under heating for 11 hours, after which it was concentrated under reduced pressure. The residue was poured over water and extracted with ethyl acetate. The organic layer was washed with a saturated aqueous solution of sodium hydrogen carbonate 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, v/v) to yield diethyl 4,5-dihydro-8-methylthiobenzo[2,1-c:3,4-b′]dithiophene-2,6-dicarboxylate (0.15 g, 52%), which was then recrystallized from ethyl acetate-hexane. Yellow prisms. Melting point 107-108° C.

1. temperaturerefluxed
2. temperatureunder heating for 11 hours
3. concentrationafter which it was concentrated under reduced pressure
4. additionThe residue was poured over water
5. extractionextracted with ethyl acetate
6. washThe organic layer was washed with a saturated aqueous solution of sodium hydrogen carbonate and water in that order
7. dry with materialdried (MgSO4)
8. distillationafter which the solvent was distilled off
9. washeluted with ethyl acetate-hexane (1:7