Pyrido (3 ', 4': 4,5) thieno (2,3-d) pyrimidine 3-substituted, their preparation and use.

3, 4, 5, 6, 7, 8-hexahydro [3?, 4?; 4, 5] thieno [2, 3- d] pyrimidine-3-substi tuidos of formula I wherein R 1 is a hydrogen atom , an alkyl group having 1 to 4 carbon atoms, an acetyl group, a phenylalkyl radical having 1 to 4 carbon atoms, the aromatic compound being substituted, if desired, by halogen, alkyl having 1 to 4 carbon atoms, trifluoromethyl, hydroxy, alkoxy having 1 to 4 carbon atoms, amino, cyano or nitro, or meaning a phenylalkanone radical, it being possible for the phenyl group substituted by halogen, R2 is a phenyl, pyridyl, pyrimidinyl or pyrazinyl, or substituted mono- by halogen atoms, alkyl having 1 to 4 carbon atoms, trifluoromethyl groups, trifluoromethoxy, hydroxy, alkoxy having 1 to 4 carbon atoms, amino, monomethylamino, dimethylamino, cyano or nitro, which may be condensed, if desired, with a benzene ring which may be mono- or disubstituted, optionally, by halogen atoms Alkyl having 1 to 4 carbon atoms, hydroxy, trifluoromethyl, alkoxy having 1 to 4 carbon atoms, amino, cyano or nitro, and can optionally contain a nitrogen atom, or which may be condensed with a ring 5- or 6-membered ring which may contain 1 to 2 oxygen atoms, A represents NH or an oxygen atom, Y is CH2, CH2-CH2, CH2-CH2-CH2 or CH2-CH, Z represents a nitrogen atom, one carbon atom or CH, may be the bond between Y and Z also a double bond, n is the number 2, 3 or 4 and their salts compatible from the physiological standpoint.