Sodium hydride → 2-Methoxyethyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide

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Reaction Steps

To a solution of 3.0 g. (0.015 mole) of N-methylsaccharin and 2.3 g. (0.015 mole) of 2-methoxyethyl chloroacetate in 15 ml. of dimethylsulfoxide at 40° C. was added 810 mg. (0.033 mole) of sodium hydride over a 2 hour period. The resulting reaction mixture was stirred for 2 hours at 40°-50° C. and was then quenched in 5% hydrochloric acid solution. The resulting suspension was extracted with methylene chloride (2×100 ml.) and the organic layers separated, combined and washed with water (50 ml.) and a brine solution (50 ml). The organic layer was dried over magnesium sulfate and concentrated to an oil, 4.1 g. The product was purified by dissolution of the residue in 5 ml. of acetone and addition of the acetone slowly to 125 ml. of 0.25N hydrochloric acid. The suspension was allowed to stir for several hours, and was then filtered and dried 2.6 g. (55%). The product is indistinguishable from that reported in U.S. patent application Ser. No. 191,716, filed Sept. 29, 1980.

Provenance & Evidence