M R shielding measurements reveal that thiolo-imidazole and -tetrazole exist almost entirely as the thione form. Quantitative estimates of the position of tautomerism in 1,2,3-triazole and tetrazole are obtained. The reported assignments are supported by means of INDO/S-SOS shielding calculations.
A 15N NMR study of some azoles
β Scribed by L. Stefaniak; John D. Roberts; M. Witanowski; G. A. Webb
- Publisher
- John Wiley and Sons
- Year
- 1984
- Tongue
- English
- Weight
- 334 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0749-1581
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β¦ Synopsis
3 NMR data are reported for 42 szoles, taken mostly at a standard concentration and in a common solvent (0.5 M dimethyl sulfoxide with a 0.01 M increment of Cr(acac), for each nitrogen atom present). Signal assignments were assisted by comparison witb ' " N line widths, the use of zJ(15N'H) couplings, and shielding calculations obtained by the INDO/S-SOS approach. The generally large Merences in nitrogen-shielding changes permitted rather facile shift assignments.
π SIMILAR VOLUMES
N NMR chemical shift data are presented for 14 azolopyridines, together with the results of INDO/S-SOS calculations of nitrogen shieldings. Previous ' " N NMR results for some of these compounds are reinterpreted. The ' " N data and their assignments are shown to be reliable for the indolizine nitro
The 15N chemical shifts and a large collection of coupling constants pertaining to azoles have been gathered from the literature. To complete this collection and to check some anomalies, the spectra of 14 compounds in several solvents were recorded again and 31 compounds were studied for the first t
## Abstract A natural abundance ^15^N NMR study was carried out on a series of 1β and 2βmonoβ and 1,5β and 2,5βdisubstituted tetrazoles in different media. An erroneous assignment given in the literature for 2,5βdisubstituted tetrazoles was corrected using MNDO molecular orbital calculations and th