Recent Study on Synthesis of Novel Pyrimido Oxazine and Their Derivatives

In present report novel oxazine were prepared from starting materials chalcone and urea (1). The resulting compound 6-(4-chlorophenyl)-4-phenyl-6H-1,3-Oxazin-2-amine(2) was further reacted with ethyl 2-cyano-3,3-bis (methylthio) acrylate in the presence of catalytic amount of potassium carbonate in DMF under reflux condition that offered novel 2-(4-chlorophenyl)-8-(methylthio)-6-oxo-4-phenyl-4,6,9,9 a-tetrahydropyrimido[2,1-b][1,3]oxazine-7- carbonitrile (3). The synthesized compounds were characterized by spectral methods. The compound (3) possesses replaceable methylthio (-SCH3) group at 8 position. The compound (3) react with various nucleophiles like substituted aromatic amines, aromatic phenols, hetryl amines and active methylene compounds to give 2-(4- chlorophenyl)-8-(substituted)-6-oxo-4-phenyl-4,6,9,9a-tetrahydropyrimido[2,1-b][1,3] oxazine-7-carbonitrile in good yields. In compound (3) cyano and thiomethyl groups are at adjacent position it also undergoes cyclization to give polycyclic heterocyclic compound.