Ethyl Acetate → N-(6-chloro-5-phenyl-1H-indazol-3-yl)butanamide

Participants

Reaction Conditions

Reaction Steps

8.8 cm3 of tetrabutylammonium fluoride as a 1M solution in tetrahydrofuran are added to 650 mg of N-[5-phenyl-6-chloro-1-[[2-(trimethylsilyl]ethoxy]methyl]-1H-indazol-3-yl]butanamide, described previously, in 25 cm3 of tetrahydrofuran. The medium is maintained at 67° C. for 20 hours and is then allowed to return to room temperature and 75 cm3 of ethyl acetate are added; the organic phase is washed with 75 cm3 of saturated aqueous sodium hydrogen carbonate solution and then with 2×75 cm3 of saturated aqueous sodium chloride solution. The organic phase is dried over magnesium sulphate, filtered and evaporated to dryness under reduced pressure (2 kPa; 45° C.). The residue is purified by chromatography under an argon pressure of 50 kPa, on a column of silica gel (particle size 40-60 μm; diameter 3.5 cm), eluting with a cyclohexane/ethyl acetate mixture (70/30 by volume). The fractions containing the expected product are combined and evaporated under reduced pressure (2 kPa; 50° C.) and the residue is taken up in 15 cm3 of diisopropyl ether, filtered off on a sinter funnel and washed successively with 10 cm3 of diisopropyl ether and with 5 cm3 of ethyl acetate. After drying under reduced pressure (90 Pa; 50° C.), 240 mg of N-(5-phenyl-6-chloro-1H-indazol-3-yl)butanamide are obtained in the form of a white solid melting at 235° C.

Provenance & Evidence