Ethanol → Ethyl 4,5-dihydro-8-methylthio-2-phenylthieno[3,4-e]benzothiazole-6-carboxylate

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Reaction Steps

A mixture of ethyl 5-bromo-4,5,6,7-tetrahydro-3-methylthio-4-oxobenzo[c]thiophene-1-carboxylate (6.99 g), thiobenzamide (5.49 g) and ethanol (150 ml) was refluxed under heating for 3 hours, after which it was poured over water (500 ml) and extracted with ethyl acetate-tetrahydrofuran (3:1, v/v). The organic layer was washed with water and dried (MgSO4), after which the solvent was distilled off. The residue was subjected to silica gel column chromatography and eluted with chloroform-hexane (1:1, v/v) to yield ethyl 4,5-dihydro-8-methylthio-2-phenylthieno[3,4-e]benzothiazole-6-carboxylate (2.63 g, 33.9%),. which was then recrystallized from ethyl acetate-hexane. Colorless needles. Melting point 153-154° C.

Provenance & Evidence