A Facile Method for the Synthesis of 6-Alkylation Products of 1,3-Dialkyl-5-fluorouracil.

6-Alkyl-1,3-diakyl-5-fluorouracil (3a–3f) were synthesized by the reaction of the lithium derivative of 1,3-dialkyl-5-fluorouracil with methyl iodide or alkyl trifluoromethanesulfonate. We found that the methylated products were ethyl-substituted derivatives, not methyl-substituted derivatives. A possible mechanism is also proposed for the ethylation process.