Water → (Chlorothio)formyl chloride

Participants

Reaction Steps

Chlorocarbonylsulfenyl chloride was prepared by a literature procedure. A mixture of 784.9 g (4.22 mol) of trichloromethanesulfenyl chloride and 76 g (4.22 mol) of water dissolved in 886 ml of concentrated H2SO4 was stirred at 45°-50° for 1 hour in a 51. flask, at which time the initially-copious HC1 evolution had ceased. (Foaming presented problems in the beginning.) The mixture was transferred to a separatory funnel, and after 15 minutes, the layers were separated. The top, fluid layer, which amounted to 404.3 g (3.08 mol, 73% yield) of fairly pure chlorocarbonylsulfenyl chloride, was added to 373 g (3.08 mol) of benzamide in 1 1. of toluene in a 5 1. flask fitted with stirrer and reflux condenser. The mixture was stirred vigorously and was heated gently to 58°. A mildly exothermic reaction carried the temperature to 65° with foaming and vigorous gas evolution. The mixture was heated at 65° for 20 minutes, at 70° for 8 hours, at 70°-110° for 0.5 hours, and at 110° for 0.75 hours, at which time gas evolution had ceased. The reaction mixture was concentrated under vacuum to 1.5 mm and 90°. The residue was heated with 650 ml of methylcyclohexane; the mixture was treated with charcoal, filtered, and allowed to cool. The resultant solid was recrystallized from 650 ml of methylcyclohexane, heated to 75 (charcoal treatment and filtration) to give 375 g of very pale yellow solid, 5-phenyl-1,3,4 -oxathiazol-2-one, m.p. 64°-67°. An additional 27.2 g of product, m.p. 64°-67°, was obtained from the filtrates. The total yield, 412.2 g, corresponds to 75% of the theoretical amount.

Provenance & Evidence