Hydrochloric Acid → 6,6-diphenyl-1-(2-trimethylsilanylethoxymethyl)-6,7-dihydro-1H-indazole-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A solution of 5 g of 6,6-diphenyl-6,7-dihydro-1H-indazole-3-carboxylic acid in 100 cm3 of dimethylformamide is added dropwise to a suspension of 1.45 g of sodium hydride (at 60% in oil) in 25 cm3 of dimethylformamide cooled to a temperature in the region of 0° C. After stirring for 2 hours at a temperature in the region of 20° C., the reaction mixture is cooled to a temperature in the region of 0° C. and 4.18 cm3 of (2-chloromethoxyethyl)trimethylsilane are added dropwise. The mixture is stirred for about 20 hours at a temperature in the region of 20° C. After cooling this mixture to a temperature in the region of 0° C., 100 cm3 of water and 16 cm3 of aqueous 1N hydrochloric acid solution are added. The mixture is extracted three times with 100 cm3 of ethyl acetate. The combined organic phases are washed with three times 100 cm3 of water, dried over magnesium sulphate, filtered and concentrated to dryness under reduced pressure (13 kPa). After flash chromatography on a column of silica [eluent: dichloromethane/methanol (98/2 by volume)], 1.8 g of 6,6-diphenyl-1-(2-trimethylsilanylethoxymethyl)-6,7-dihydro-1H-indazole-3-carboxylic acid are thus obtained in the form of a resin, the characteristics of which are as follows:

Provenance & Evidence