4-Toluenesulfonyl chloride → 2,3-Dihydro-4-[(4-methylphenyl)sulfonyloximino]-2-phenyl-4H-1-benzopyran

Participants

Reaction Steps

A solution of p-toluenesulfonyl chloride (83 g) in 125 ml pyridine was added dropwise at 5°-10° to 2,3-dihydro-4-(hydroxyimino)-2-phenyl-4H-1-benzopyran (52 g) in 230 ml pyridine. The reaction mixture was then stirred for 20 hours at room temperature, poured into ice-water to separate out the title compound, which was filtered, washed several times with water, then once with ether, and finally dried in air. Yield: 85.5 g; m.p. 141°-143°.

Provenance & Evidence