Al-Mousawi SM, Moustafa MS. 2-Arylhydrazononitriles as building blocks in heterocyclic synthesis: A novel route to 2-substituted-1,2,3-triazoles and 1,2,3-triazolo[4,5-b]pyridines.
Beilstein J Org Chem 2007;
3:12. [PMID:
17355619 PMCID:
PMC1847523 DOI:
10.1186/1860-5397-3-12]
[Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2006] [Accepted: 03/13/2007] [Indexed: 11/10/2022] Open
Abstract
2-Arylhydrazono-3-oxobutanenitriles 2 was reacted with hydroxylamine hydrochloride to yield amidooxime 3. This was cyclized into the corresponding oxadiazole 4 on refluxing in acetic anhydride. When refluxed in DMF in presence of piperidine, the corresponding 1,2,3-triazoleamine 5 was formed. The latter was acylated to 6 by addition of acetic anhydride while treatment of 5 with malononitrile gave the 1,2,3-triazolo [4,5-b]pyridine 8. Treatment of acetyl derivative 6 with DMFDMA gave enaminone 9. The enaminone 9 was coupled with benzenediazonium chloride to yield phenylazo-1,2,3-triazolo [4,5-b]pyridine 10. Trials to convert compound 14 into 1,2,3-triazolo [4,5-d]pyrimidine 15via refluxing in AcOH/NH4OAc failed. Instead the hydrolyzed product 5 was formed.
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