Hydrochloric Acid → Methyl 2-(chlorosulfonyl)-6-fluorobenzoate

Participants

Reaction Conditions

Reaction Steps

108 g of methyl 6-fluoroanthranilate and 45 g of sodium nitrite in 106 ml of water were added, via 2 feed devices, to 250 ml of stirred concentrated hydrochloric acid at 5° C. over the course of 1 hour in such a way that the ester component was present in excess. After the reaction mixture had been stirred for 20 minutes at 55° C.-8° C. it was poured, in one shot, into a previously prepared solution of 53 g of sulfur dioxide, 1.7 g of copper(II) chloride and a small amount of water in 200 ml of 1,2-dichloroethane, and the resulting mixture was stirred for 10 minutes thereafter. It was then slowly heated to 50° C. and stirred for 11/2 hours while introducing 46 g of sulfur dioxide. It was then cooled to 20° C. and 5.5 g of chlorine were introduced over 20 minutes, with stirring. Stirring was then continued for 20 minutes, after which the organic phase was separated off. It was washed with water, dried over magnesium sulfate and evaporated, giving 105 g of the compound shown in the title, in the form of a brownish oil.

Provenance & Evidence