Alpha-1-p-chlorobenzoyl-2-methyl-5-methoxyindolyl-3

Preparation of 3-indolylacetic acid derivative of the formula (I): The method gives a more convenient synthesis than the previously described route (US.Patent 3,161,654). To 300 cc methanol water (4:1) contng. 0.2 equivalents of the sodium salt of alpha(1-p-chlorobenzoyl-2-methylindolyl(3)) acetic acid, 0.05 equivalents of ferrous sulphate and 20 g suspended iron powder is added in 30 min. at 20-25 deg. a methanol solution of CH3OCl. The reaction mixture is stirred for a further hour and filtered. The precipitate is washed with 100 ml methanol at 50 deg.C and the wash liquor and the filtrate are purified. alpha(1-p-chlorobenzoyl-2-methyl-5-methoxyindolyl-(3)) acetic acid.