NOUVEAUX DERIVES DE TYPE PYRIMIDINONE, PROCEDE POUR LEUR PREPARATION ET COMPOSITION PHARMACEUTIQUE LES CONTENANT

Composés de formule générale (1) : Compounds of the formula (I) (I) in which R1 and R2 each may represent hydrogen, alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, or alkyl, substituted by hydroxy, C1-3 alkoxy, amino, C1-3 alkylamino or di-C1-3 alkylamino or R1 and R2 together with the nitrogen atom to which they are attached form an alicyclic heterocyclic ring which may be unsubstituted or may be substituted by one or more C1-3 alkyl groups or a hydroxy group and/or may contain another heteroatom are described. Alk is a straight lower alkylene chain, Q is a furan or thiophen ring, the furan ring optionally bearing a further substituent R5 adjacent to the group R1R2NAlk- or Q represents a benzene ring. R5 represents halogen or C1-3 alkyl which may be substituted by a hydroxy or C1-3 alkoxy group; X represents -CH2-, -O- or -S-; n represents zero or 1; m represents 2, 3 or 4; Y represents =O or =S; R3 represents hydrogen in which case R4 represents methyl or R3 represents -(CH2)pV(CH2)qAr, phenyl, or alkyl in which case R4 represents hydrogen; V represents -CH2-, -O-, or -S-; p represents zero, 1, 2 or 3; q represents zero, 1, 2 or 3; the sum of p+q being 3 or less; Ar represents an aromatic carbocyclic or heterocyclic ring being optionally substituted by at least one C1-3 alkyl, C1-3 alkoxy C1-3 alkyl, hydroxy, C1-3 alkoxy, methylenedioxy, halogen, trifluoromethyl or di-C1-3 alkylamino group; except that when n is zero and X is oxygen then Q represents a benzene or thiophen ring. The compounds of formula (I) have pharmacological activity as selective histamine H2-antagonists.