Pyrimidine derivatives and related compounds. Part 48. Uracil ring transformation: conversion of 5-nitrouracils into 5-carbamoyluracils

Abstract
1,3-Disubstituted 5-nitrouracils (1) react with malonamide in ethanolic sodium ethoxide to afford 1-substituted 5-carbamoyluracils (3)via rearrangement of the N(3)–C(4)–C(5) portion of the uracil. This ring transformation has been applied to the preparation of 2′,3′,5′-tri-O-acetyl-5-carbamoyluridine (8).