With the compound represented by the general formula (I - X), CuCN or NaCN is reacted in the solvents such as DMF, N,N-dimethylformamide and hexamethylphosphoric triamide (HMPA), to obtain a compound of the formula: ##STR32## Therein, above reaction proceeds also without solvents, and use of a catalyst including ferric chloride is also effective.