Hydrochloric Acid → 1H-indazol-5-yl 3-fluorobenzenesulfonate

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Reaction Steps

1H-Indazol-5-yl 3-fluorobenzenesulfonate can be obtained in the following way: a suspension of 193 mg of 1-acetyl-1H-indazol-5yl 3-fluorobenzenesulfonate and of 0.19 ml of hydrochloric acid (d=1.18) in 1.65 ml of distilled water is brought to reflux for 16 hours. After returning to a temperature in the region of 20° C., the reaction medium is basified to a pH in the region of 8 with a saturated aqueous sodium hydrogencarbonate solution and extracted with two times 10 ml of dichloromethane. The pooled organic extracts are dried over calcium chloride, filtered and concentrated by evaporation under reduced pressure. The transluscent oil obtained is taken up with 2 ml of diisopropyl ether and concentrated by trituration. The solid obtained is separated by filtration, washed with two times 1 ml of diisopropyl ether and dried under reduced pressure. 100 mg of 1H-indazol-5-yl 3-fluorobenzenesulfonate are thus obtained in the form of a whiteish solid melting at 104° C. (analysis C13H9FN2O3S, % calculated C, 53.42; H, 3.10; F, 6.50; N, 9.58; O, 16.42; S, 10.97. % found C, 53.5; H, 2.9; F, 6.2; N, 9.6).

Provenance & Evidence