László Pongó

On triazoles XI . structure elucidation of isomeric 1,2,4-triazolopyrimidinones

Abstract The structure of Isomeric 3 – 6 type triazolo-pyrimidinones and their N-methylated and N-benzylat-ed derivatives was elucidated. In spite of the good agreement between the carbonyl bonds of derivatives 3 – 6 (R1= CH3, R=H, Q=SCH3) and their structure the IR method did not prove to be characteristic in general for the above structures. In contrast to the results reported previously it was found that the 3 - 6 type derivatives are well characterised by their UV spectra taken in neutral solution. The 13C-NMR spectra gave an unequivocal proof of the above structures corroborating the conclusions drawn from the UV measurements.

On triazoles XIX: The reaction of 5-amino-1,2,4-triazoles with functionalized acetoacetic esters

SummaryDifferent “functionalized” alkyl 3-oxo-butyrates (2) were reacted with 5-amino-3-Q-1H-1,2,4-triazoles (1) to yield3 and4 type 1,2,4-triazolo[1,5-a]pyrimidinones. In case of2 (R1=methyl,R2=1-ethoxycarbonylethyl,R3=ethyl) beside the corresponding derivative4 the unexpected 5,6-dihydro-6,8-dimethyl-7-ethoxycarbonyl-3-methylthio-1,2,4-triazolo[4,3-a]-1,3-diazepin-5(9H)-one (7) was isolated, representing a novel ring system.ZusammenfassungVerschiedene „funktionalisierte“ 3-Oxo-buttersäurealkylester (2) wurden mit 5-Amino-3-Q-1H-1,2,4-triazolen (1) umgesetzt, wobei 1,2,4-Triazolo[1,5-a]pyrimidinone der Typen3 und4 erhalten wurden. Im Fall von2 (R1=Methyl,R2=1-Ethoxycarbonylethyl,R3=Ethyl) wurde neben dem erwarteten Derivat4 das unerwartete 5,6-Dihydro-6,8-dimethyl-7-ethoxycarbonyl-3-me-thylthio-1,2,4-triazolo[4,3-a]-1,3-diazepin-5(9H)-on (7) isoliert, welches ein neues Ringsystem darstellt.

On triazoles, IX HMO calculations of tautomeric 1,2,4-triazole derivatives

HMO calculations were performed for all possible tautomeric forms of different 1,2,4-triazole derivatives1–4 and their condensed ring analogues5–8. The resonance energies obtained showed this method useful for the differentiation of the tautomeric structure of the planar monocyclic 1,2,4-triazole derivatives but it did not give satisfactory results in case of their non-planar condensed ring analogues.ZusammenfassungDie HMO-Methode wurde für alle möglichen tautomeren Formen der 1,2,4-Triazol-Derivate1–4 und deren kondensierte Analogen5–8 verwendet. Die berechneten Resonanzenergien bewiesen, daß dieHückel-Methode gute Resultate für die Unterscheidung verschiedener tautomerer Formen der planaren 1,2,4-Triazol-Derivate, aber nicht für deren nicht-planare kondensierte Analogen ergibt.