5-Fluorouracil derivatives. XII. Synthesis and antitumor activity of .ALPHA.-alkylthiomethyl-, .ALPHA.-alkylsulfinylmethyl-, .ALPHA.-alkylsulfonylmethyl-, and .ALPHA.-acylthiomethyl-5-fluorouracils.

Abstract

For the purpose of diminishing the toxicity of 5-fluorouracil (1) and obtaining biologically active derivatives of 1 suitable for oral administration, alkylthiomethyl, alkylsulfinylmethyl, alkylsulfonylmethyl, and acylthiomethyl groups were introduced at the 1- and 3-positions of 1. The antitumor activity of these synthetic compounds was tested against L1210 leukemia in mice. 1-Alkylthiomethyl-5-fluorouracils showed weak antitumor activity at a high dose (300 mg/kg).