A One-Pot Biginelli Synthesis and Characterization of Novel Dihydropyrimidinone Derivatives Containing Piperazine/Morpholine Moiety.

Enaminones, 4-methyl-1-[4-(piperazin/morpholin-1-yl) phenyl] pent-2-en-1-one (IIa⁻b) were synthesized by refluxing 1-[4-(piperazin/morpholin-1-yl) phenyl] ethan-1-one (Ia⁻b) with dimethylformamide dimethylacetal (DMF⁻DMA) without any solvent. The three dimensional structure of enaminone (IIb) containing morpholine moiety was confirmed by single crystal X-ray crystallography. Finally, the dihydropyrimidinone derivatives (1⁻20) were obtained by reacting enaminones (IIa⁻b) with urea and different substituted benzaldehydes in the presence of glacial acetic acid. Dihydropyrimidinone derivatives containing piperazine/morpholine moiety were synthesized in a good yield by means of simple and efficient method.