Cyclocondensation Reations of 3-Amino-l,2,4-triazole with 3-(Benzyl idene)-6-fl uoro-th iochroman-4-ones to Tetracycl ically Fused Dihydropyrimidines and Pyrimidines

摘要

The effects of reaction temperature, solvents, reaction time and 7-aryl on the cyclocondensation reactions of 3-amino-l,2,4-triazole with 3-(benzylidene)-6-fluorothiochroman-4-ones were studied. The experimental results show that except tetracyclic fused dihydropyrimidines and pyrimidines were produced simultaneously in the cyclo- condensation reactions, the dihydropyrimidines could be directly converted into pyrimidines without any dehydro-genizing reagent under high temperature. The structures of the new synthesized compounds were confirmed by 1H NMR, MS spectra, elemental analysis, and X-ray single crystallography. The cyclocondensation mechanism for producing the tetracyclically fused dihydropyrimidines and pyrimidines was discussed.