Triazoloazine-diazomethylazine valence isomerization. [1,2,3]triazolo[1,5-a]pyridines and 2-diazomethylpyridines

Aylward, Nigel, Winter, Hans-Wilhelm, Eckhardt, Ulrich and Wentrup, Curt (2016) Triazoloazine-diazomethylazine valence isomerization. [1,2,3]triazolo[1,5-a]pyridines and 2-diazomethylpyridines. Journal of Organic Chemistry, 81 2: 667-672. doi:10.1021/acs.joc.5b02639

Author Aylward, Nigel
Winter, Hans-Wilhelm
Eckhardt, Ulrich
Wentrup, Curt
Title Triazoloazine-diazomethylazine valence isomerization. [1,2,3]triazolo[1,5-a]pyridines and 2-diazomethylpyridines
Formatted title
Triazoloazine-diazomethylazine valence isomerization. [1,2,3]triazolo[1,5-a]pyridines and 2-diazomethylpyridines
Journal name Journal of Organic Chemistry   Check publisher's open access policy
ISSN 1520-6904
Publication date 2016-01-15
Sub-type Article (original research)
DOI 10.1021/acs.joc.5b02639
Open Access Status Not Open Access
Volume 81
Issue 2
Start page 667
End page 672
Total pages 6
Place of publication Washington, DC, United States
Publisher American Chemical Society
Language eng
Formatted abstract
2-Diazomethylpyridines 1D and 6D, the valence isomers of [1,2,3]triazolo[1,5-a]pyridines 1T and 6T, have been observed directly at ∼2080 cm–1 by a combination of mild flash vacuum pyrolysis (FVP) at 200–600 °C with low temperature IR spectroscopy. Calculations confirm a ca. 17 kcal/mol barrier for the formation of 2-diazomethylpyridine 1D from [1,2,3]triazolo[1,5-a]pyridine 1T, the diazo compound lying ca. 5 kcal/mol above the triazole. In the higher temperature range (400–600 °C) 2-diazomethylpyridine 1D eliminates N2 with formation of 2-pyridylcarbene 2 and rearrangement to 1-cyanocyclopentadiene 4. 2-Diazomethylpyridine 1D undergoes 1,3-dipolar cycloaddition with tetracyanoethylene (TCNE) at 20–90 °C to yield 3-(2-pyridyl)cyclopropanetetracarbonitrile 11 and 3-(tricyanovinyl)-[1,2,3]triazolo[1,5-a]pyridine 13T via unobserved pyrazolines 10 and 12. FVP of triazole 13T affords an IR absorption at 2080 cm–1 ascribed to the corresponding diazo compound 13D.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Chemistry and Molecular Biosciences
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