Sodium hydride → 2-Benzo[1,3]dioxol-5-ylmethyl-4-(benzo[1,3]dioxol-5-ylsulfanyl)-1,1-dioxo-1,2-dihydro-1lambda6-benzo[e][1,2]thiazine-3-carboxylic acid methyl ester

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Reaction Steps

To 2-Benzo[1,3]dioxol-5-ylmethyl-4-hydroxy-1,1-dioxo-1,2-dihydro-1λ6 -benzo[e][1,2]thiazine-3-carboxylic acid methyl ester in dichloromethane (6 mL) and pyridine (0.65 mL, 7.75 mmol) was added trifluoromethanesulfonic anhydride (0.32 mL, 1.71 mmol). This mixture was stirred at room temperature for 30 minutes. Diluted with ethyl acetate (100 mL), washed with 1N HCl (2×50 mL), brine (50 mL), dried with magnesium sulfate and then evaporated in vacuo to afford the crude 2-benzo[1,3]dioxol-5-ylmethyl-6,7-dimethoxy-1,1-dioxo-4-(trifluoro-methanesulfonyloxy)-1,2-dihydro-1λ6 -benzo[e][1,2]thiazine-3-carboxylic acid methyl ester. A solution of this ester, in DMF (3 mL), was added to sodium 1,3-benzodioxole-5-thiolate (0.31 g, 2.0 mmol) {prepared by dissolving 1,3-benzodioxole-5-thiol (0.31 g, 2.0 mmol) in DMF (3 mL) and stirring with sodium hydride (0.081 g, 2.0 mmol) for 5 minutes} in DMF (3 mL). After stirring at room temperature for 16 hours the mixture was diluted with ethyl acetate (100 mL), washed with 1N NaOH(2×50 mL), brine (50 mL), dried with magnesium sulfate, and evaporated in vacuo. Silica gel column chromatography eluting with 25% ethyl acetate in hexane afforded the title compound as a foam (0.64 g, 79%);

Provenance & Evidence