NEW MATERIAL:A 3-carbomethoxyindole derivative expressed by formula I (R1 is hydroxy or lower alkoxy; R2 is H or amino-protecting group) and salts thereof.

EXAMPLE: 1-Carbobenzoxy-3-carbomethoxyindole.

USE: Useful as an intermediate for medicines, agricultural chemicals and fine chemicals, especially as an intermediate for CC-1065, etc., having a structure effectively used as, e.g. a carcinostatic agent.

PREPARATION: A phenylhydroxylamine derivative expressed by formula II (R3 is H, hydroxy or lower alkoxy; R4 is amino-protecting group) is allowed to react with methyl propiolate in the presence of a base in an organic solvent such as benzene, preferably at 15-30°C to afford the objective compound expressed by formula III in formula I. The mixing ratio of the compound expressed by formula II to the methyl propiolate is preferably within the range of (1:1) to (1:5).