Synthesis of Various Derivatives of a Novel Heterocyclic System of Tetrazolo[1,5-a][1,2,3]triazolo[4,5-d]pyrimidine

Abstract

1,2,3-Triazole has become one of the most important heterocycles in current chemistry research,<br><br>due to its important industrial, agrochemical and pharmaceutical applications, especially<br><br>in biological science, material chemistry, and medicinal chemistry [1]. Additionally, the<br><br>chemistry of the tetrazole ring is gaining increasing attention due to its importance in a variety<br><br>of synthetic and industrial processes and excellent properties as a metabolically stable isosteric<br><br>replacement for the carboxylic acid moiety and as a cis-peptide bond mimetic [2]. Tetrazoles<br><br>have also been used as precursors to other heterocycles and in high energy compounds<br><br>[3]. In the present work, initially the reaction of 2,4-dichloro-6-methylpyrimidin-5-<br><br>amine (1) with different primary amines in refluxing i-PrOH gave the corresponding secamino<br><br>derivatives which were consequently treated with NaNO2/HCl solution to yield quantitatively<br><br>the corresponding diazo derivatives of 5-chloro-3-alkyl-7-methyl-3H-<br><br>[1,2,3]triazolo[4,5-d]pyrimidine (2a-e). Further reaction of compounds (2a-e) with NaN3 in<br><br>EtOH was resulted in various derivatives of novel heterocyclic system of tetrazolo[1,5-<br><br>a][1,2,3]triazolo[4,5-d]pyrimidine (3a-e) that are in equilibrium with azide forms.