Methanol → methylphosphonic acid 3-(1H-indol-2-yl)-1H-indazol-5-yl ester methyl ester

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Reaction Steps

Methylphosphonic acid 3-(1H-indol-2-yl)-1H-indazol-5-yl ester methyl ester is prepared according to procedure F using 150 mg of methylphosphonic acid bis-(4-nitrophenyl) ester, 4 ml of dichloromethane, 100 mg of 3-(1H-indol-2-yl)-1H-indazol-5-ol, 67 μl of 1,8-diazabicyclo[5.4.0]undec-7-ene and 4 ml of dichloromethane. After stirring for 3 hours, a solution of 100 μl of methanol in 2 ml of dichloromethane is added dropwise. The reaction medium is stirred for approximately 16 hours and then concentrated to dryness under reduced pressure. The oil obtained is purified on a 5 g Interchim flash cartridge of silica with a particle size of 15-35 μ. Eluent: 30% of ethyl acetate in cyclohexane, then with 80% of ethyl acetate in methanol. The solvents are evaporated off under reduced pressure and the product obtained is crystallized from ethyl acetate. 36 mg of methylphosphonic acid 3-(1H-indol-2-yl)-1H-indazol-5-yl ester methyl ester are obtained in the form of white crystals.

Provenance & Evidence