IMIDAZOLYLPHENYL AMIDINES

Object of the present invention are new pharmacologically active amidine derivatives of 2-substituted 4-phenylimidazole of formula in which R representa a linear or branched alkyl group, a hydroxy group, a C1-3 alkoxy group, a mercapto group, C1-3 alkylthio group, a halogen atom, a C1-3 alkylsulfinyl or alkylsulfonyl group, a sulfamoyl group, an amino group which may be substituted by one or two alkyl groups having 1 to 3 carbon atoms, an acylamino group or a phenyl group; R1 and R2, which may be the same or different, represent a hydrogen atom or an alkyl group; R3 represents a linear or branched alkyl group containing optionally one heteroatom such as an oxygen, a sulphur or a nitrogen atom, an alkenyl group, an alkynyl group, a cyano group, an aryl or an aralkyl group optionally substituted, a cycloalkyl or cycloaliphatic alkyl group, a substituted or unsubstituted heterocyclilalkyl or heterocyclic group; R4 represents a hydrogen atom, a C1-3 alkyl or alkoxy group, a halogen atom, a cyano or carbamoyl group, tautomeric forms thereof and acid addition salts thereof. Processes for the preparation of the compounds of formula (1) and their intermediates as well as the pharmaceutical compositions containing them are also object of this invention. The new compounds are H2-receptor blocking agents which inhibit the gastric acid secretion and are useful antiulcer agents.