Substituted 4-pyrimidone compounds, compositions and methods of use

A compound of the formula:

• ##STR9## wherein Het' is a 2- or 4-imidazolyl ring optionally monosubstituted by lower alkyl, halogen, trifluoromethyl or hydroxymethyl, a 2-pyridyl ring optionally monosubstituted by lower alkyl, lower alkoxy, halogen, amino or hydroxy, a 2-pyridyl ring which is disubstituted by lower alkoxy groups, or which has a phenyl, carbocyclic or cyclic ether ring having two oxygen atoms fused to it, a 2-thiazolyl ring, a 3-isothiazolyl ring optionally monosubstituted by chlorine or bromine, a 3-(1,2,5)-thiadiazolyl ring optionally monosubstituted by chlorine or bromine, or a 2-(5-amino-1,3,4-thiadiazolyl)ring;
• Z is sulphur or a methylene group;
• X is oxygen or sulphur;
• W is methylene, oxygen or sulphur;
• m and n are such that their sum is from 1 to 4 when W is oxygen or sulphur, or from 0 to 4 when W is methylene;
• A is a 2,3-dihydro-1,4-benzodioxinyl or a 1,3-benzodioxolyl ring, a phenyl ring substituted with one or more phenylloweralkoxy (said phenyl being optionally monosubstituted by chloro or methoxy), loweralkoxyloweralkoxy, trifluoromethyl, di(loweralkyl)amino, phenoxy, halophenoxy, lower alkoxyphenoxy, phenyl, halophenyl or lower alkoxyphenyl groups and when W is not a methylene group, A may also be phenyl;
• and Y.sup.3 is hydrogen or lower alkyl;
• or a pharmaceutically acceptable acid addition salt thereof.