Azo-coupling of pyrazole-3(5)-diazonium chlorides with cyanothioacetamide: a convenient synthesis of pyrazolo[5,1-c][1,2,4]triazine-3-carbothioamides

Pyrazolotriazines: Biological activities, synthetic strategies and recent developments

Heterocyclic compounds create an important class of molecules that demonstrates various chemical spaces for the definition of effective medicines. Many N-heterocycles display numerous biological activities. Among condensed heterocycles, pyrazolotriazine derivatives have received the attention of researchers owing to the extensive spectrum of biological activities. The reactivity of identified compounds was similar to the free azoles and triazines. The pyrazolotriazine scaffold exhibited antiasthma, antiinflammatory, anticancer, antithrombogenic activity and showed activity for major depression and pathological anxiety. Pyrazolotriazine derivatives also exhibited antibacterial, anticancer, antimetabolites, antidiabetic, antiamoebic, anticonvulsant, antiproliferative activity, human carbonic anhydrase inhibition, cyclin-dependent kinase 2 inhibition, tyrosinase and urease inhibition, MAO-B inhibition, TTK inhibition, thymidine phosphorylase inhibition, tubulin polymerization inhibition, protoporphyrinogen oxidase inhibition, GABA_A agonistic activity, hCRF1 receptor antagonistic activity, and CGRP receptor antagonistic activity. This paper structurally categorized various pyrazolotriazines to isomeric classes into six groups that containing pyrazolo [1,5-d] [1,2,4] triazine, pyrazolo [5,1-c] [1,2,4] triazine, pyrazolo [3,4-e] [1,2,4] triazine, pyrazolo [4,3-e] [1,2,4] triazines, pyrazolo [1,5-a] [1,3,5] triazine, and pyrazolo [3,4-d] [1,2,3] triazine and expressed biological activity, the synthetic procedures for each class of pyrazolotriazines, structure-activity relationship and their mechanism of action. Generally, this review summarily indicated the past and present studies about the discovery of new lead compounds with good biological activity.

Synthesis of some new pyrazolo[1,5-a]pyrimidine, pyrazolo[5,1-c]triazine, 1,3,4-thiadiazole and pyridine derivatives containing 1,2,3-triazole moiety

Background

Pyrazolo[1,5-a]pyrimidines are purine analogues. They have beneficial properties as antimetabolites in purine biochemical reactions. This division compounds have attracted wide pharmaceutical interest because of their antitrypanosomal activity.

Results

The present work depicts an effective synthesis convention of pyrazolo[1,5-a]pyrimidines, pyrazolo[5,1-c]triazines, thieno[2,3-b]pyridines and polysubstituted pyridines containing 1,2,3,-triazole moiety from the reaction of sodium 3-(5-methyl-1-(p-toly)-1H-1,2,3-triazol-4-yl)-3-oxoprop-1-en-1-olate with the fitting heterocyclic amines and its diazonium salt, and active methylene compounds, individually. Likewise, thiazoles and, 1,3,4-thiadiazoles were obtained from 2-bromo-1-(5-methyl-1-(p-tolyl)-1H-1,2,3-triazol-4-yl)ethanone and some reagent such as hydrazonoyl chlorides and halo ketones. The newly synthesized compounds were established by elemental analysis, spectral data, and alternative synthetic route whenever possible.

Conclusions

New series of pyrazolo[1,5-a]pyrimidines, pyrazolo[5,1-c]triazines, thieno[2,3-b]pyridines and polysubstituted pyridines containing the 1,2,3,-triazole moiety were synthesized via reactions of sodium 3-(5-methyl-1-(p-toly)-1H-1,2,3-triazol-4-yl)-3-oxoprop-1-en-1-olate with the appropriate heterocyclic amines and its diazonium salt. In addition, 1,3,4-thiadiazoles and, 1,3-thiazoles were acquired in a decent yield via the reaction of substituted thiourea with the appropriate hydrazonoyl chlorides and halogenated ketenes.Graphical abstract