A process for the preparation of new pharmacologically active katekolijohdannaisten

The invention relates to a process for preparing pharmacologically active catechol derivatives of the formula I, in which R1 and R2 denote hydrogen or different hydrocarbon chains or rings which are optionally substituted, or R1 and R2 together form a lower alkylidene or cycloalkylidene group, X denotes an electronegative substituent in the 5 or 6 position, and R3 denotes different individual groups such as halogen, nitro, cyano, etc., or optionally substituted saturated or unsaturated hydrocarbon chains or rings. The chains and rings can also contain heteroatoms, in particular nitrogen. The process involves several different variants which can be used when compounds are prepared in which the nature and size of the substituent R3 vary. The compounds according to the invention can be used as so-called COMT inhibitors in medicinal use.