Butler, Richard N., Hanniffy, John M., Stephens, John C. and Burke, Luke A. (2008) A Ceric Ammonium Nitrate N-Dearylation of N-p-Anisylazoles Applied to Pyrazole, Triazole, Tetrazole, and Pentazole Rings: Release of Parent Azoles. Generation of Unstable Pentazole, HN5/N5 -, in Solution. JOC - Journal of Organic Chemistry, 73 (4). pp. 1354-1364. ISSN 0022-3263
PDF
JS_Ceric_Ammonium.pdf
Download (188kB)
JS_Ceric_Ammonium.pdf
Download (188kB)
Abstract
The reaction of cerium(IV) ammonium nitrate (CAN) with a range of N-(p-anisyl)azoles in acetonitrile
or methanol solvents leads to N-dearylation releasing the parent NH-azole and p-benzoquinone in
comparable yields. The scope and limitations of the reaction are explored. It was successful with 1-(panisyl)
pyrazoles, 2-(p-anisyl)-1,2,3-triazoles, 2-(p-anisyl)-2H-tetrazoles, and 1-(p-anisyl)pentazole. The
dearylation renders the p-anisyl group as a potentially useful N-protecting group in azole chemistry. The
azole released in solution from 1-(p-anisyl)pentazole is unstable HN5, the long-sought parent pentazolic
acid. p-Anisylpentazole samples were synthesized with combinations of one, two, and three 15N atoms
at all positions of the pentazole ring. The unstable HN5/N5
- produced at -40 °C did not build up in the
solution but degraded to azide ion and nitrogen gas with a short lifetime. The 15N-labeling of the N3
- ion
obtained from all samples proved unequivocally that it came from the degradation of HN5 (tautomeric
forms) and/or its anion N5
- in the solution.
Item Type: | Article |
---|---|
Additional Information: | The definitive version of this article is available at JOC - Journal of Organic Chemistry (2008) Vol.73 No.4 pp.1354-1364. DOI: 10.1021/jo702423z |
Keywords: | Ceric Ammonium Nitrate N-Dearylation; N-p-Anisylazoles; Pyrazole; Triazole; Tetrazole; Pentazole Rings; Parent Azoles; Unstable Pentazole; HN5/N5; |
Academic Unit: | Faculty of Science and Engineering > Chemistry |
Item ID: | 3829 |
Depositing User: | Dr John Stephens |
Date Deposited: | 22 Aug 2012 15:40 |
Journal or Publication Title: | JOC - Journal of Organic Chemistry |
Publisher: | American Chemical Society |
Refereed: | Yes |
Related URLs: | |
URI: | https://mu.eprints-hosting.org/id/eprint/3829 |
Use Licence: | This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here |
Repository Staff Only (login required)
Downloads
Downloads per month over past year