Ethanol → 5,6-Dihydro-4H-thieno[2,3-b]thiopyran-2-sulfonamide 7,7-dioxide

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Reaction Steps

A solution of 6H-thieno[2,3-b]thiopyran-2-sulfonamide-7,7-dioxide (3.05 g, 0.011 m) is absolute ethanol (130 ml) and methanol (20 ml) was hydrogenated on a Parr apparatus at 40 psi with 5% palladium on carbon catalyst (250 mg) at ambient temperature. After 15 minutes, 10% palladium on carbon catalyst (350 mg) was added, followed by an identical addition after 30 minutes. After 16 hours, the catalyst was filtered and the filtrate was concentrated in vacuo. The residue was dissolved in absolute ethanol (100 ml) and methanol (50 ml) and hydrogenated at 50 psi with 10% palladium on carbon catalyst (500 mg) for 16 hours. The catalyst was filtered off and the filtrate was evaporated under reduced pressure. The solid residue was chromatographed on silica gel, eluting with 10% methanol-chloroform to give 2.33 g (76%) of product.

Provenance & Evidence