Novel non-nucleobase-derived inhibitors of the angiogenic enzyme, thymidine phosphorylase, have been identified using molecular modelling, synthesis and biological evaluation. These inhibitors are 2, 4, 5-trioxoimidazolidines bearing N-(substituted) phenylalkyl groups, together with, in most cases, N′-(CH2) n-carboxylic acid, ester or amide side chains. The best compound from this series is 3-(2, 4, 5-trioxo-3-phenylethyl- ...