Synthesis and study of the azide-tetrazole tautomerism in 2-azido-4-(trifluoromethyl)-6-R-pyrimidines (R = H, 4-ClC6H4)
- Authors: Nikolaenkova Е.B.1, Aleksandrova N.V.1, Mamatyuk V.I.1,2, Krivopalov V.P.1
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Affiliations:
- N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences
- Novosibirsk State University
- Issue: Vol 67, No 5 (2018)
- Pages: 893-901
- Section: Full Articles
- URL: https://journals.rcsi.science/1066-5285/article/view/242543
- DOI: https://doi.org/10.1007/s11172-018-2154-z
- ID: 242543
Cite item
Abstract
Azide-tetrazole equilibrium in azidopyrimidines bearing trifluoromethyl group on the example of 2-azidopyrimidines has been studied. The latter were synthesized via nitrosation of 2-hydrazino-4-trifluoromethylpyrimidine and reaction of NaN3 with 4-trifluoromethyl-2- chloro-6-(4-chlorophenyl)pyrimidine. The tautomeric equilibrium 5-trifluoro methyl tetrazolo[1,5-a]pyrimidine ⇆ 2-azido-4-trifluoromethylpyrimidine was observed in the absence of solvent and in DMSO-d6 solution, whereas in CDCl3 only an azide form exists. For 2-azido- 4-trifluoromethyl-6-(4-chlorophenyl)pyrimidine, only an azide isomer was detected in CDCl3 solution, and in DMSO-d6 solution it is in equilibrium with 5-(trifluoromethyl)-7-(4-chlorophenyl) tetrazolo[1,5-a]pyrimidine (the tautomer ratio is 99 : 1). Thermodynamic and kinetic parameters of 5-trifluoromethyltetrazolo[1,5-a]pyrimidine ⇆ 2-azido-4-trifluoromethylpyri midine tautomeric rearrangement in DMSO-d6 for 5-trifluoromethyltetrazolo[1,5-a]pyrimidine were determined using the exchange spectroscopy (EXSY) technique.
About the authors
Е. B. Nikolaenkova
N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences
Email: krivic@nioch.nsc.ru
Russian Federation, 9 prosp. Akad. Lavrentieva, Novosibirsk, 630090
N. V. Aleksandrova
N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences
Email: krivic@nioch.nsc.ru
Russian Federation, 9 prosp. Akad. Lavrentieva, Novosibirsk, 630090
V. I. Mamatyuk
N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences; Novosibirsk State University
Email: krivic@nioch.nsc.ru
Russian Federation, 9 prosp. Akad. Lavrentieva, Novosibirsk, 630090; 2 ul. Pirogova, Novosibirsk, 630090
V. P. Krivopalov
N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences
Author for correspondence.
Email: krivic@nioch.nsc.ru
Russian Federation, 9 prosp. Akad. Lavrentieva, Novosibirsk, 630090