Acetic Acid → 4-Acetoxy-5,6-dihydro-4H-thieno[2,3-b]thiopyran-2-sulfonamide-7,7-dioxide

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

5,6-Dihydro-4-hydroxy-4H-thieno[2,3-b]thiopyran-2-sulfonamide-7,7-dioxide (2.00 g, 0.0071 m), glacial acetic acid (0.92 g, 0.015 m) and 4-dimethylaminopyridine (0.085 g, 0.0007 m) were dissolved in dry tetrahydrofuran (30 ml) and the solution was cooled to 0° C. under nitrogen and stirred while a solution of dicyclohexylcarbodiimide (1.61 g, 0.0078 m) in dry tetrahydrofuran (10 ml) was added over 10 minutes. After stirring at 0° C. for 1 hour and at ambient temperature for 2 hours, an additional 0.46 g (0.0077 m) of glacial acetic acid was added and stirring was continued at ambient temperature for one hour more. The mixture was filtered and the solid was washed with tetrahydrofuran. The combined filtrate and washings were evaporated in vacuo to give a quantitative yield (2.31 g) of crude product. This material was combined with 1.14 g of identical product from a previous run and chromatographed on silica gel, eluting with 10% methanol-chloroform, to yield 2.57 g (75%) of product. Recrystallization from nitromethane afforded an analytical sample melting at 187.5°-188.5° C.

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