Abstract: Compounds of general formula: ##STR1## (wherein X represents a halogen atom or a trifluoromethyl group; R.sup.1 and R.sup.2, which may be the same or different, each represents a hydrogen atom, or a C.sub.1-4 alkyl group, and R.sup.3 represents a hydrogen atom or a C.sub.1-5 saturated or unsaturated, straight or branched acyclic aliphatic group; a C.sub.3-8 saturated or unsaturated cyclic aliphatic group; a heterocyclic substituted aliphatic group; an araliphatic group; or a heterocyclic or carbocyclic aryl group; any of said groups optionally carrying one or more substituents selected from halogen, oxo, hydroxy, mercapto, C.sub.1-4 alkyl, C.sub.1-4 alkoxy, C.sub.1-4 alkanoyloxy and amino) and, where an acidic or basic group is present, physiologically compatible salts thereof have been found to be of use in combating abnormal cell proliferation.The compounds of formula I may be prepared by reaction of a 5-halo- or 5-trifluoromethyl-pyrimidin-2-one with an appropriate isocyanate.

Abstract: Compounds of the formula: ##STR1## wherein X represents a halogen atom;R.sup.1 and R.sup.2, which may be same or different, each represents a hydrogen atom, or a C.sub.1-4 alkyl group;Het represents a C-attached 3-9 membered, saturated, unsaturated or aromatic heterocyclic ring containing one or more hetero atoms selected from O, N and S and optionally carrying a fused ring and/or optionally substituted by one or more substituents selected from halogen atoms and hydroxy, C.sub.1-4 alkoxy, amino, acylamino, nitro, oxo, C.sub.1-4 alkyl groups and monocyclic carbocyclic and heterocyclic aryl groups having 5 to 8 ring members; such a heterocyclic ring being saturated and having only a single heteroatom when there are 3 or 4 ring members; andalk represents a C.sub.