1,8-Diazabicyclo(5.4.0)undec-7-ene → methylphenylphosphinic acid 3-(1H-indol-2-yl)-1H-indazol-5-yl ester

Participants

Reaction Steps

A solution of 497 mg of 50%-pure methylphenylphosphinic acid 4-nitrophenyl ester in 8 ml of dichloromethane is stirred at ambient temperature. A suspension of 403 mg of 3-(1H-indol-2-yl)-1H-indazol-5-ol and 268 μl of 1,8-diazabicyclo[5.4.0]undec-7-ene in 12 ml of dichloromethane is added dropwise. The reaction medium is stirred at ambient temperature overnight and then evaporated to dryness under reduced pressure in a rotary evaporator. The reaction crude is purified by flash chromatography on a cartridge of 50 g of silica 15-35 μm. 300 mg of methylphenylphosphinic acid 3-(1H-indol-2-yl)-1H-indazol-5-yl ester are collected and recrystallized from ethyl acetate to obtain 220 mg of methylphenylphosphinic acid 3-(1H-indol-2-yl)-1H-indazol-5-yl ester.

Provenance & Evidence