Preparation of 5-per-fluoroalkyl-uracil derivatives used as intermediates for e.g. anti-viral drugs

摘要

Preparation of 5-perfluoroalkyl-5,6-dihydrouracil derivatives of formula (I) comprises reaction an alpha -perfluoroalkylacrylic acid derivative of formula (II) with a urea derivative of formula (III) in the presence of acetic anhydride in the presence of acetic anhydride and removing the acetic acid formed during the reaction. H2C=C(Rf)-COOH (II) R1NHCONHR2 (III) R1, R2 = H, methyl or ethyl; and Rf = 1-10C perfluoroalkyl. Also claimed is the preparation of 5-perfluoroalkyl-5-bromo-6-hydrouracil derivatives of formula (IV) by reaction of (I) with bromine in water.