ChemInform Abstract: An Efficient One‐Pot Synthesis of Pyrimido[2,1‐b][1,3]oxazine Derivatives via the Reaction of Isocyanides with Dialkyl Acetylenedicarboxylates in the Presence of 5‐Substituted Uracils.

Abstract The reaction between dialkyl acetylenedicarboxylates (II) and alkyl isocyanides (III) produces a reactive 1:1 adduct which is trapped by uracil derivatives (I) to provide the highly functionalized pyrimidooxazines (IV).