Methanol → methylphosphonic acid methyl ester 3-[5-(2-morpholin-4-ylethoxy)-1H-indol-2-yl]-1H-indazol-5-yl ester

Participants

Reaction Steps

A suspension of 170 mg of methylphosphonic acid bis-(4-nitrophenyl)ester (prepared according to procedure E) and 189.7 mg of 3-[5-(2-morpholin-4-yl-ethoxy)-1H-indol-2-yl]-1H-indazol-5-ol in 17 ml of dichloromethane (stabilized with amylene) is stirred at ambient temperature. A solution of 75 μl of DBU in 500 μl of dichloromethane is added dropwise over 10 minutes. Stirring is maintained overnight. 204 μl of methanol are added with 75 μl of DBU. The solution is stirred for 24 hours. The reaction medium is concentrated under vacuum and the crude is then taken up with 25 ml of ethyl acetate and washed with 4 times 25 ml of distilled water. The organic phase is dried over magnesium sulfate, filtered and concentrated under vacuum. The reaction crude is purified by flash chromatography on 5 g of 40-63 μm silica. Eluents: 98/2 then 95/5 dichloromethane/methanol. 95 mg of methylphosphonic acid methyl ester 3-[5-(2-morpholin-4-yl-ethoxy)-1H-indol-2-yl]-1H-indazol-5-yl ester are collected.

Provenance & Evidence