4-(ω-(2-Amino-6-hydroxy-4-oxo-3,4-dihydro-5-pyrimidinyl)alkyl)benzoic acids II-VI were prepared by condensation of triethyl 2-(ω-(4-carboxyphenyl)alkyl)-1,3-propanedioates VII-XI with guanidine and subsequent saponification. Compounds II-VI had an antineoplastic effect in animals with experimental transplantable tumours. The effect of compound II was comparable with that of compound I (Damvar).