Methyl iodide → 3-ethoxycarbonylmethyl-4-hydroxy-2-methyl-2H-thieno[2,3-e]1,2-thiazine 1,1-dioxide

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Reaction Steps

1.93 G. (7 mmol) of 3-ethoxycarbonylmethyl-4-hydroxy-2H-thieno[2,3-e]-1,2-thiazine 1,1-dioxide are dissolved in 4 ml. of absolute dimethylformamide and added dropwise during 30 minutes at 0° C. to a stirred suspension of 0.185 g. (7.7 mmol) of sodium hydride in 2 ml. of absolute dimethylformamide. The mixture is stirred for a further 1 hour at room temperature. There are then added firstly 0.53 ml. (1.2 g.; 8.45 mmol) of methyl iodide and, after 30 minutes, a further 0.25 ml. (0.565 g; 4 mmol) of methyl iodide and the mixture is allowed to react for 1 hour. After distillation of the solvent, the residue is taken up in 30 ml. of 0.5-N hydrochloric acid and 30 ml. of methylene chloride, the organic phase is separated and the aqueous layer is back-extracted twice with a small amount of methylene chloride. The combined organic extracts are dried over sodium sulfate and evaporated. The crystalline residue is digested with a small amount of cold ethanol. There is obtained 3-ethoxycarbonylmethyl-4-hydroxy-2-methyl-2H-thieno[2,3-e]-1,2-thiazine 1,1-dioxide of melting point 161°-163° C. (crystal transformation at 151°-152° C).

Provenance & Evidence