Synthesis of 6-aminouracils and pyrrolo[2,3-d]pyrimidine-2,4-diones and their inhibitory effect on thymidine phosphorylase.

Inhibitors of thymidine phosphorylase (dThdPase) are expected to suppress the growth and metastasis of tumor cells by inhibition of angiogenesis and were designed by utilizing the three dimensional structure of the enzyme. 5-Substituted 6-aminouracils (5) and 7-substituted pyrrolo[2,3-d]pyrimidine-2,4-diones (6) were synthesized and tested for inhibition of human placenta thymidine phosphorylase. 5-Bromo-6-aminouracil (5d), 5-cyano-6-[3-(methylamino)propyl]-uracil (5e), and 7-(2-aminoethyl)-pyrrolo[2,3-d]pyrimidine-2,4-dione (6c) inhibited dThdPase with IC50s of 7.6, 3.8 and 44.0 microM, respectively.