5-Fluorouracil Derivatives. X

With the aim of diminishing the toxicity of 5-fluorouracil (1) and obtaining biologically active derivatives of 1 suitable for oral administration, α-alkoxyalkyl groups were introduced at the 1-, 3-and 1, 3-positions of 1. Alkoxyalkylation can be effected by four methods : (i) reaction of 1-alkoxyalkyl chloride (2) with 1, (ii) reaction of acetal with 2, 4-bis (trimethylsiloxy)-5-fluoropy-rimidine, (iii) addition reaction of α-unsaturated ether with 1, (iv) aminolysis of 1-alkylthio-carbonyl-3-(1-alkoxyalkyl)-5-fluorouracil. The toxicity of the products was less than that of 1, and some of these compounds showed moderate antitumor activity against L-1210 leukemia.