Syntheses and Antitumor Activities of 5-(Substituted-methyl)-6-carbamoyluracils

5-Chloromethyl-6-ethoxycarbonyluracil (5) was prepared from furo [3, 4-d] pyrimidine-2, 4, 7 (1H, 3H, 5H)-trione (4). Reaction of 5 with some nucleophilic reagents such as secondary amines, alcohols and sodium thiolates afforded 5-(substituted-methyl)-6-ethoxy-carbonyluracils. By treatment of the corresponding esters with methanolic ammonia or ammonia water, 5-(substituted-methyl)-6-carbamoyluracils were prepared. The antitumor activities of the newly synthesized compounds were examined against L-1210 cells in vitro.