|
|||||
|
|
Synthesis of novel heterocycles using 1,2,3-triazole-4-carbohydrazides as precursors |
|
| Authors: | Hanan A Mohamed Rizk E Khidre Benson M Kariuki Gamal A El-Hiti |
| Institution: | 1. Applied Organic Chemistry Department, National Research Center, Dokki, Giza, Egypt
Department of Chemistry, College of Science and Humanities, Shaqra University, Duwadimi, Saudi Arabia;2. Chemical Industries Division, National Research Center, Dokki, Giza, Egypt Chemistry Department, Faculty of Science, Jazan University, Jazan, Saudi Arabia;3. School of Chemistry, Cardiff University, Cardiff, UK;4. Cornea Research Chair, Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia |
| Abstract: | Herein, we report the synthesis of various heterocyclic ring systems containing 1,2,3-triazole from the reactions of acid hydrazides and commercially available reagents, using efficient and simple procedures. Reactions of certain 1,2,3-triazole-4-carbohydrazides and α-bromoketones in boiling ethanol afforded the corresponding hydrazones rather than the expected triazines. The hydrazones could also be synthesized in 85-90% yield via an alternative pathway that involved the reaction of 1,2,3-triazole-4-carbohydrazides and 4-acetyl-1,2,3-triazoles in boiling ethanol containing glacial acetic acid. Reaction of one of the 4-carbohydrazides with carbon disulfide, followed by the reaction with hydrazine hydrate, gave 4H-1,2,4-triazole-3-thiol in 73% yield, which further reacted with other α-bromoketones in boiling ethanol to afford 7H-1,2,4]triazolo3,4-b]1,3,4]thiadiazines in 82-84% yields. Additionally, reactions of certain carbohydrazides with ethyl 2-cyano-3,3-bis(methylthio)acrylate gave 1-aryl-1H-1,2,3-triazole-4-carbohydrazides rather than the expected 1H-pyrazole-4-carboxylates. |
| Keywords: | |