PRODUCTION OF INDOLE DERIVATIVE AND ITS INTERMEDIATE

PROBLEM TO BE SOLVED: To efficiently obtain an indole derivative of high purity in high yield that is useful in the production of medicines and the like without any trouble of toxicity and safety by reducing a specific halogenated indole derivative, followed by alcoholysis or aminolysis. SOLUTION: A 2-oxoindoline derivative represented by formula I [R1 is hydroxymethyl, carboxyl, a lower alkoxycarbonyl, an (N-substituted) carbamoyl; R2 is a (substituted) aryl, a (substituted) heteroaryl or the like; n is 0-6] is halogenated to give a 2-halogenated indole derivative, for example, ethyl 1-[1-(2- fluorophenethyl)-piperidin-4-yl]-2-chloroindol-6-yl}acetate or the like. Then, the resultant 2-halogenated indole derivative is reduced, then, when necessary, subjected to alcoholysis or aminolysis to give the objective indole derivative represented by formula III, for example, 1-[1-(2-fluorophenethyl)piperidin-4-yl]-6- methylcarbamoylmethylindole or the like.