A “Neat” Synthesis of Substituted 2-Hydroxy-pyrido[1,2-a]pyrimidin-4-ones

We report the synthesis of a series of substituted 2-hydroxy-pyrido[1,2-a]pyrimidin-4-ones through solvent-free condensation of of 2-aminopyridines and diethyl malonate. This method is contrasted with three reported general procedures for the preparation of these compounds, revealing the simple, “neat” synthesis conditions are suitable for a number of derivatives. Environmental, safety, and economic factors were considered in exploring this effective and robust synthetic method.