Synthesis of 6-Nitroderivatives of Oxazolo[3,2-a]-pyridines and Their Reactions with Nucleophiles
Abstract
:Introduction
Results and Discussion
Phenacylation of 5-nitro-2-pyridone
Х in Аr | Chemical shift, ppm | J, Hz | |||||
---|---|---|---|---|---|---|---|
H6 | H4 | H3 | -CH2- | HAr | J46 | J34 | |
4-Me | 9.17 | 8.16 | 6.50 | 5.60 | 7.95-7.93 7.37-7.35 | 3.2 | 9.4 |
4-NO2 | 9.22 | 8.24 | 6.59 | 5.74 | 8.45-8.40 8.32-8.27 | 2.8 | 10.1 |
4-Cl | 9.20 | 8.19 | 6.52 | 5.73 | 8.18-8.15 7.65-7.62 | 3.1 | 9.7 |
Synthesis of 2-aryl-6-nitrooxazolo[3,2-a]pyridinium perchlorates.
X in Ar | Chemical shift, ppm. | J, Hz | |||||
---|---|---|---|---|---|---|---|
H5 (d) | H7 (dd) | H8 (d) | H3 (s) | HAr (m) | J57 | J78 | |
CH3 | 10.28 | 9.03 | 8.43 | 9.11 | 7.82-7.80; 7.35-7.32 | 1.3 | 9.3 |
NO2 | 10.35 | 9.06 | 8.51 | 9.18 | 8.47-8.42; 8.36-8.31 | 1.6 | 10.0 |
Cl | 10.31 | 9.04 | 8.46 | 9.13 | 8.12-8.08; 7.87-7.82 | 1.3 | 9.8 |
Reaction of the salts II with nucleophiles.
R2N | R' | Chem. shifts, ppm. | J, Hz | ||||||
---|---|---|---|---|---|---|---|---|---|
H1. | H3, d | H4, d | Hoxazol, s | HAr, m | HR', s | HR | J34 | ||
Morpholine | CH3 | 8.63 (s) | 6.76 | 6.51 | 7.71 | 7.60-7.58 7.31-7.29 | 2.35 | 3.52 3.39 3.32 | 12.0 |
Pyrrolidine | Cl | 8.81 (s) | 6.82 | 6.51 | 7.80 | 7.71-7.67 7.56-7.52 | 3.73 2.92 1.73 | 12.2 | |
NH2 | CH3 | 8.95 (m) | 6.94 | 6.03 | 7.46 | 7.56-7.53 7.23-7.21 | 2.38 | 9.22 (NH2) | 13.3 |
t-BuNH | CH3 | 9.71 (d) 13.7Hz | 7.13 | 6.08 | 7.27 | 7.53-7.51 7.23-7.21 | 2.38 | 1.47(tBu) 10.13(NH) | 14.0 |
n-PrNH | CH3 | 9.31 (d) 13.81 Hz | 7.05 | 6.11 | 7.28 | 7.53-7.51 7.23-7.21 | 2.38 | 9.86 (NH) | 12.6 |
Conclusions
Experimental
General
Typical procedure for the preparation of N-phenacyl-5-nitro-2-pyridones (I).
Typical procedure for the preparation of 2-Aryl-6-nitrooxazolo[3,2-a]pyridinium perchlorates (II)
Typical procedure for the reaction of 2-aryl-6-nitrooxazolo[3,2-a]pyridinium perchlorates (II) with aliphatic amines.
Reaction of 2-(4-methylphenyl)-6-nitrooxazolo[3,2-a]pyridinium perchlorate with ammonia.
Acknowledgments
References
- Bradsher, C. K.; Zinn, M. Oxazolo[3,2-a]pyridinium salts. J. Heterocycl. Chem. 1967, 4, 66–70. [Google Scholar]
- Pauls, H.; Krohnke, F. Investigations on 2-chloropyridinium salts, II. 2 Thiopyridones and pyridol[2,1-b]thiazolium salts. Chem. Ber. 1976, 109, 3653–3660. [Google Scholar]
- Babaev, E. V. Fused Munchnones in Recyclization Tandems. J. Heterocycl. Chem. (Lectures in Heterocyclic Chemistry) 2000, 37, 519–526. [Google Scholar]
- Babaev, E. V.; Efimov, A.V.; Maiboroda, D.A. Hetarenes with a nitrogen bridging atom. 1. Phenacylation of 2-substituted 6-methylpyridines. Chem. Heteroc. Compounds (Engl. Transl.) 1995, 31, 962–968. [Google Scholar]
- Babaev, E.V.; Pasichnichenko, K.Yu.; Maiboroda, D.A. Ambident properties of the oxazolo[3,2-a]pyridinium cation in reactions with nucleophiles: forecast and experiment. Chem. Heteroc. Compounds (Engl. Transl.) 1995, 33, 338–343. [Google Scholar]
© 2003 by MDPI ( http://www.mdpi.org). Reproduction is permitted for noncommercial purposes.
Share and Cite
Bush, A.A.; Babaev, E.V. Synthesis of 6-Nitroderivatives of Oxazolo[3,2-a]-pyridines and Their Reactions with Nucleophiles. Molecules 2003, 8, 460-466. https://doi.org/10.3390/80600460
Bush AA, Babaev EV. Synthesis of 6-Nitroderivatives of Oxazolo[3,2-a]-pyridines and Their Reactions with Nucleophiles. Molecules. 2003; 8(6):460-466. https://doi.org/10.3390/80600460
Chicago/Turabian StyleBush, Alexander A., and Eugene V. Babaev. 2003. "Synthesis of 6-Nitroderivatives of Oxazolo[3,2-a]-pyridines and Their Reactions with Nucleophiles" Molecules 8, no. 6: 460-466. https://doi.org/10.3390/80600460