Generation of a 3-Allyl/Propanylthiomethyl Ketene and their [4+2] Cycloadditions With 1,3-Diazabuta-1,3-dienes: Synthesis of 5-Allyl/propargyl-thio methyl Pyrimidinones.

The manuscript describes the explorations on [4+2] cycloaddition of newly in situ generated 3-(allyl/propargyl-thio)propanone as 2π-components with functionalized 1,3-diazabuta-1,3-dienes as 4π-components for the synthesis of 5-allyl/propargyl-thio methyl pyrimidinones. The synthetic methodology is simple to operate, mild, and successful with a wide range of functionalized 1,3-diazabuta-1,3-dienes in the development of functionalized pyrimidinones. The synthesis of these functionalized pyrimidinones is significant as functionalized pyrimidinones have diverse pharmacological relevance and are useful synthons for the synthesis of condensed heterocycles.