PROCESS FOR PREPARING DERIVATIVES OF AMPOVINCAMINOLE OR THEIR PHARMACEUTICALLY ACCEPTABLE SALTS

New compounds of the general formula (I): wherein either both R and R stand for hydrogen or one of the symbols R and R is hydrogen and the other is nitro, and pharmaceutically acceptable acid addition salts thereof are prepared by reacting apovincaminol with 3,4,5-trimethoxy- benzoic acid or a reactive derivative thereof capable of acylation and, if desired, nitrating the resulting compound and separating the isomeric mixture of nitro derivatives thus obtained, and, if desired, converting the said compound or nitro derivatives into pharmaceutically acceptable acid addition salts thereof. These compounds can be used in therapy in the treatment of skin diseases associated with pathological cell proliferation and in the prophylaxis of such diseases.