Synthesis of 5-Alkoxy Pyrimidines via Enamides

Significance

Reported is the synthesis of substituted 5-alkoxypyrimidines from enamides which are derived through a stepwise three-component reaction of alkoxyallenes, nitriles, and carboxylic acids. The mechanism for this three-component reaction has been previously discussed (H.-U. ­Reissig and co-workers Chem. Eur. J. 2004, 10, 4283). Of the two sets of conditions for the final pyrimidine formation, that using ammonium acetate allowed the use of less equivalents of ammonium salt and a slightly lower temperature. However, this was not exclusively employed.