REACTIONS OF HETEROCYCLIC CATIONS WITH N-CONTAINING NUCLEOPHILES. 13. INVESTIGATION OF THE REACTION OF 2,4,6-TRIARYLPYRYLIUM SALTS WITH HYDRAZINES, SEMICARBAZIDE, AND THIOSEMICARBAZIDE

Article abstract of DOI:10.1007/BF00514471

The recyclization reactions of 2,4,6-triphenylpyrylium perchlorate with hydrazine and methyl-, phenyl-, benzoyl-, and benzalhydrazines in dimethylformamide (DMF), which proceed differently than in ethanol, were examined. 7-Oxo and 7-thioxo derivatives of 2,3a,5-triphenyl-3H-pyrazolo<1,5-c>pyrimidine were obtained by transformation of 2,4,6-triarylpyrylium salts with semicarbazide and thiosemicarbazide in DMF.The tautomeric forms of the products were established by mass spectrometry and chemical transformations.