5,6-dihydro-[1,2,4]triazolo[1,5-c]quinazolines. Message 4. Spirocompounds with [1,2,4]triazolo[1,5-c]quinazolines moieties. The synthesis and spectral

Abstract

The present article describes the synthesis of novel spiro-condensed [1,2,4]triazolo[1,5-c]quinazolines. [2-(3-Aryl1H-1,2,4-triazol-5-yl)phenyl]amines were used as effective precursors for the synthesis of the compounds mentioned above. The experimental data have shown that the reaction of the initial anilines with cycloalkanones (cyclopentanone, cyclohexanone) allowed to obtain products of binucleophilic addition, namely spiro-condensed compounds with [1,2,4]triazolo[1,5-c]quinazolines moieties. The initial anilines also readily react with a conformationally rigid bicyclo[2.2.1]heptan-2-one yielding the corresponding spiroderivatives, whereas the reaction with camphor and menthone has failed due to the steric hindrance. It has been found that [5+1]-cyclocondensation of the initial anilines with heterocyclonones (1-R-piperidone-4, dihydrothiophene-3(2H)-one, dihydro-2H-pyran-4(3H)-one, dihydro-2H-thiopyran-3(4H)-one) proceeds without peculiarities and with formation of the corresponding 2’-aryl-6’H-spiro[1,2,4]triazolo[1,5-c]quinazolines. The reaction with 5-R-1H-indole-2,3-dione (isatine) and its N-substituted derivatives also proceeds without any peculiarities with formation of aryl-2’-aryl6’H-spiro[(indol-3,5’-[1,2,4]triazolo[1,5-c]quinazolines] with high yields. The purity of the compounds obtained has been proven by the LC-MS (APCI) method, their structures have been confirmed by the complex of physicochemical methods, including 1H and 13C NMR, IR-, MS-(EI) – spectrometry and the X-ray study. The peculiarities of 1H and 13C NMR-spectra of the compounds synthesized are discussed. It has been shown that signals of NH-protons in the 1H NMR-spectrum and C-5’ in the 13C NMR-spectrum are characteristic for the compounds synthesized.