FIELD: organic chemistry and technology. SUBSTANCE: invention relates to method of synthesis of pharmaceutically active compounds of the formula (V): 
where R1 and R2 mean independently hydrogen or lower alkyl at condition that in position 2 of central bicycle none or at least one of both radicals R1 and R2 means a substituent distinct from hydrogen and taken from methyl and ethyl; A means -(CH2)n where n = 1, 2, 3 or 4; R3,R4,R5,R6 mean independently each of other hydrogen or lower alkyl, or their tautomers, or their salts as indicated in description for the formula (I): 
where R1,R2 and A have values indicated above, or their salts. Invention relates to using compounds (I) as intermediate compounds also. EFFECT: improved methods of synthesis. 3 cl
