The Synthesis Of Polysubstituted Pyrimidines And N-Substituted Quinazolinones

In1893, Italian chemist Pietro Biginelli reported the synthesis of functionalized3,4-dihydropyrimidin-2（¹H）-ones via three-component condensation reaction of anaromatic aldehyde, urea, and ethyl acetoacetate. In the1980s, such Biginelli-typedihydropyrimidones have received a considerable amount of attention due to thescope of the original cyclocondensation reaction was gradually extended by variationof all three building blocks, allowing access to a large number of multifunctionalizeddihydropyrimidines of this type. In this thesis, the recent developments in thesynthesis of quinazolin（th）ione and DHPMs are reviewed and three new methods forthe synthesis of N/C2-multifunctionalized pyrimidines are described. The researchresults are summarized below:1. In environmentally friendly PEG-400reaction medium, I₂and Cs₂CO₃ascatalyst for the aromatization reactions and Amines to give C2-substitutedpyrimidines. We can control the different temperatures to get a different product. Atroom temperature we can get C-S-N bonds, but at140oC we can get C-Nproducts. The structures of the typical compounds are confirmed by X-ray,¹HNMR,13C NMR detection.2. Novel quinazolinones modified with N3-alkyloxymethyl, aminomethyl andazidomethyl groups can be regioselectively obtained over their isomeric N1compounds in good yields by reaction of quinazolinone with paraformaldehyde andalcohol, amine, sodium azide, acid and phenol, respectively, by a one-pot two-stepstrategy in the presence of chlorotrimethylsilane.3. Aza-Michael addition reaction of4-aryl-7,7-dimethyl-1,2,3,4,5,6,7,8-octahydroquinazoline-2,5-diones to alpha, beta-ethylenic compounds in thepresence of KF/Al2O3furnish N3-or N1substituted quinazolinone derivatives. Thestructures of the typical compounds are confirmed by X-ray,¹HNMR,13C NMRdetection.