1-benzoyl-2-methyl-3-indolylacetic acid derivs

preparation of 3-indolylacetic acid derivatives of formula:- (I) where R = methoxy or dimethylamino The synthesis is considerably shorter than the method already described for the preparation of (I), U.S.Patent 3,161,654. 5.9 g. concentrated sulphuric acid is cooled to 5 deg.C and to it is slowly added with stirring 0.92 g. anhydrous formic acid while cooling to maintain the temperature between 0 and 5 deg.C. To this mixture 1.65 g. of 1-p-chlorobenzoyl-2-methyl-5-methoxy-3-indolylmethanol is added in portions at 0 deg.C in a nitrogen atmosphere. After standing 6 hr. at this temperature, the mixture is poured into 50 ml. ice cold water and the precipitate is filtered off, washed with water and recrystallised from t-butanol, to give the 1-p-chlorobenzoyl-2-methyl-5-methoxy-3-indolylacetic acid.