Methyl chloroacetate → 3-Oxo-naphth[2,1-d]isothiazoline-2-acetic acid methyl ester-1,1-dioxide

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Reaction Steps

70.0 gm (0.30 mol) of 3-oxo-naphth[2,1-d]isothiazoline-1,1-dioxide were added to a solution of 7.82 gm (0.34 gm-atom) of sodium in 300 ml of absolute methanol. The majority of the alcohol was subsequently distilled off, and the residual sodium salt of 3-oxo-naphth[2,1-d]isothiazoline-1,1-dioxide was dissolved in 100 ml of absolute dimethylsulfoxide. At a temperature of 50° C, 43.41 gm (0.40 mol) of methyl chloroacetate were added dropwise to this solution. The resulting mixture was stirred at room temperature for half an hour, then slowly heated to 130° C and finally kept at this temperature for 2.5 hours. Then, the dimethylsulfoxide was distilled off in vacuo, andthe residue was stirred into a solution of 40 gm of sodium acetate in 400 ml of water, filtered off and washed with water and ice-cold methanol, yielding 90.0 gm (98% of theory) of 3-oxo-naphth[2,1-d]isothiazoline-2-acetic acid methyl ester-1,1-dioxide, m.p. 188° C (methanol/ethylene chloride).

Provenance & Evidence