| abstract |
Claim 1: Process for the preparation of racemic and optically active derivatives of 4-chloro-3- [5- chloro-1- (2,4-dimethoxybenzyl) -3-alkyl-2-oxo-2,3-dihydro acid -1H-indole-3-yl) benzoic of the general formula (1) where R represents an H atom or a C1-4 straight or branched chain alkyl group, and R1 represents a C1- straight or branched chain alkyl group 4, characterized in that it is carried out by benzilating a racemic or optically active derivative of 4-chloro-3- (5- chloro-3-alkyl-2-oxo-2,3-dihydro-1H-indole-3 acid -il) benzoic of the general formula (2) where R and R1 represent the foregoing in an ether solvent in the presence of a phase transfer catalyst and a solid base free of water with a 2,4-dimethoxybenzyl halide , prepared in situ, of the general formula (3) where X represents a halogen atom, and if desired, separating a racemic compound from the general formula (1) in its isomers optically You activate by methods known per se. |