1-Bromo-2-Chloroethane → 5-benzyloxy-3-[1-tert-butoxycarbonyl-5-(2-chloro-ethoxy)-1H-indol-2-yl]indazole-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 100 mg of 5-benzyloxy-3-(1-tert-butoxycarbonyl-5-hydroxy-1H-indol-2-yl)indazole-1-carboxylic acid tert-butyl ester and 132 μl of 1-bromo-2-chloroethane in 5 ml of dichloromethane is mixed with an aqueous solution of 72 mg of tetrabutylammonium bromide and of 270 μl of 2N sodium hydroxide in 5 ml of distilled water. The reaction mixture is stirred vigorously at 20° C. for 6 hours. After separation by settling out and washing with water (4×5 ml), the organic extracts are combined, dried over magnesium sulfate and then evaporated under reduced pressure. The crude compound obtained is purified by preparative LC/MS. The fractions containing the expected compound are combined and evaporated under reduced pressure to obtain 18.1 mg of 5-benzyloxy-3-[1-tert-butoxycarbonyl-5-(2-chloroethoxy)-1H-indol-2-yl]-indazole-1-carboxylic acid tert-butyl ester, which is characterized as follows:

Provenance & Evidence