REACTIONS OF HETEROCYCLIC CATIONS WITH N-CONTAINING NUCLEOPHILES. 15. REACTION OF 2,6-DIPHENYLPYRYLIUM PERCHLORATE WITH SEMI- AND THIOSEMICARBAZIDES

Article abstract of DOI:10.1007/BF00474352

The reaction of 2,6-diphenylpyrylium perchlorate with semi- and thiosemicarbazides in ethanol leads to 1-carbamoyl- and 1-thiocarbamoyl-3-phenyl-5-phenacyl-4,5-dihydropyrazoles, the cyclization of which yields 2,5-diphenyl-7-oxo(thio)-pyrazolo<1,5-c>pyrimidines.The tautomeric form of the latter is established by comparing their electronic absorption spectra with the spectra of the methyl derivatives.