The pyrimidine moiety is one of the most widespread heterocycles in biologically occurring compounds, such as nucleic acids components (uracil, thymine and cytosine) and vitamin B1. Due to its prebiotic nature to living cells in biodiversity, it is an highly privileged motif for the development of molecules of biological and pharmaceutical interest. This present work deals with the exploration of chemistry and medicinal diversity of pyrimidine which might pave way to long await discovery in therapeutic medicine for future drug design .An efficient multicomponent one pot synthesis of 1) Methyl-6-methyl-4-phenyl -2-thioxo-1, 2, 3, 4-tetrahydro pyrimidine 2) 5-acetyl-1, 2, 3, 4-Tetrahydro pyrimidine-2-thiones. 3) Synthesis and bioactivity of the derivatives of 1-(4-(heteroaryl)-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl)ethanone. The synthesis is based on the reaction of readily available substituted aryl aldehyde, ethylacetoacetate, acetyl acetone and thiourea, followed by Methanesulphonic acid catalysed dehydration. The products are obtained in good yield under mild, solvent cum catalysed conditions.