Hydrochloric Acid → 2,2-Dimethyl-2,3-dihydro-1-benzofuran-7-sulfonyl chloride

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반응 단계

A diazonium salt was prepared by adding 13.8 g of sodium nitrite to a suspension of 32.6 g of 7-amino-2,3-dihydro-2,2-dimethylbenzofuran and 40 ml of concentrated sulfuric acid in 200 ml water cooled 0° to 5° C. After stirring for about 0.4 hour at 0° to 5° C., the diazonium salt suspension was poured in one portion into a mixture consisting of 170 ml of acetic acid, 40 ml of concentrated hydrochloric acid, 17 g of cupric chloride dihydrate and 30 ml of sulfur dioxide and cooled by 10° C. by an ice-water bath. The mixture was stirred about 1 hour at 15° to 25° C. Then 400 ml of 1-chlorobutane and 200 ml of water was added and the mixture was stirred and heated at 35° C. for 5 hours. After cooling to room temperature, the organic layer was separated, washed with saturated aqueous NaHCO3 and water, and dried over sodium sulfate for 0.5 hour. The solvent was evaporated under reduced pressure at less than 45° C. to give 26 g of crude 2,3-dihydro-2,2-dimethyl-7-benzofuransulfonyl chloride as an oil.

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