2-(3,5-Substituted-2-pyridylalkylamino)-5-benzyl-4-pyrimidones

A compound of formula (2):

• ##STR12## or a pharmaceutically acceptable salt thereof;
• where R.sup.1 is halogen, nitro, amino, C.sub.1-4 alkylamino, C.sub.1-4 alkanoylamino or C.sub.1-4 alkyl;
• R.sup.2 is halogen, nitro, amino, C.sub.1-4 alkylamino, C.sub.1-4 alkanoylamino, C.sub.1-4 alkyl or C.sub.3-4 alkoxy;
• provided that R.sup.1 and R.sup.2 are not both selected from amino, C.sub.1-4 alkylamino, C.sub.1-4 alkanoylamino and nitro;
• R.sup.3 is a C.sub.1-3 alkylene group;
• and
• R.sup.4 is phenyl optionally bearing one or two substituents which are the same or different and are halogen, hydroxy, C.sub.1-4 alkyl or C.sub.1-4 alkoxy or a methylenedioxy group.