RSC Advances
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Acknowledgements
AKT acknowledge DST India grant no. SR/S1/OC-42/2012 for
nancial assistance. Department of Chemistry, Faculty of
Science, BHU, Varanasi, India is acknowledged for depart-
mental facilities. SKR also acknowledges to CSIR-New Delhi for
SRF.
Notes and references
1 (a) M. E. Wall, M. C. Wani, C. E. Cook, K. H. Palmer,
A. T. Mcphail and G. A. Sim, J. Am. Chem. Soc., 1966, 88,
3888; (b) J. S. Liu, Y. L. Zhu, C. M. Yu, Y. Z. Zhou,
Y. Y. Han, F. W. Wu and B. F. Qi, Can. J. Chem., 1986, 64,
837; (c) U. Fischer, H. Mohler, F. Schneider and
U. Widmer, Helv. Chim. Acta, 1990, 73, 763; (d)
J. Kobayashi, Y. Hirasawa, N. Yoshida and H. Morita, J.
Org. Chem., 2001, 66, 5901–5904; (e) R. L. T. Parreira,
Fig. 3 The UV absorption spectra for in situ generation of compound
1b diluted in ethanol. Dilution is of z1.50 ꢁ 10ꢂ4 mol dmꢂ3 range.
Table 4 lmax values for starting materials and reaction mixture at
subsequent time gaps
˜
O. Abrahao and S. E. Galembeck, Tetrahedron, 2001, 57,
3243–3253; (f) T. Hanada, Y. Hashizume, N. Tokuhara,
O. Takenaka, N. Kohmura, A. Ogasawara, S. Hatakeyama,
M. Ohgoh, M. Ueno and Y. Nishizawa, Epilepsia, 2011, 52,
1331–1340.
2 (a) M. T. Cocco, C. Congiu and V. Onnis, ARKIVOC, 2006, 10,
116–128; (b) M. T. Cocco, C. Congiu and V. Onnis, Eur. J. Med.
Chem., 2000, 35, 545–552; (c) V. P. Litvinov, Russ. Chem. Rev.,
2003, 72, 69–85; (d) T. Murray and S. Zimmerman,
Tetrahedron Lett., 1995, 36, 7627–7630.
Compound name
lmax (nm)
Acetophenone
Acrylamide (1)
Enolate
Reaction mixture aer 15 min
Reaction mixture aer 30 min
Reaction mixture aer 50 min
Reaction mixture aer 60 min
Reaction mixture aer 70 min
Reaction mixture aer 100 min
Reaction mixture aer 150 min
279
301
241
360
356
359
359
362
359
360
3 C. Boga, A. Corradi Bonamartini, L. Forlani, V. Modarell,
L. Righi, P. Sgarabotto and P. E. Todesco, Eur. J. Org.
Chem., 2001, 1175.
¨
4 C. B. Aakeroy, A. M. Beatty, M. Nieuwenhuyzen and M. Zou,
Tetrahedron, 2000, 56, 6693–6699.
form saturated acyclic adduct. Consequently, we can say that
the addition is so fast to observe in minutes. The rst signicant
spectrum of reaction mixture was observed in 15 minutes stir-
red solution which showed lmax at 360 nm. Spectrum recorded
at subsequent time gaps showed continuous increased
absorption intensity. This indicates that the addition is faster
while cyclization is slower and thus later is rate determining
step in the reaction.
5 (a) M. Torres, S. Gil and M. Parra, Curr. Org. Chem., 2005, 9,
1757; (b) L. Carles, K. Narkunan, S. Penlou, L. Rousset,
D. Bouchu and M. A. Ciufolini, J. Org. Chem., 2002, 67,
4304–4308; (c) J. H. Rigby, Synlett, 2000, 1–12; (d) H. Baron,
F. G. P. Renfry and J. F. Thorpe, J. Chem. Soc., 1904, 85,
1726–1961.
6 (a) For a review of 2-pyridone synthesis, see: P. A. Keller, in
Science of Synthesis, ed. D. StC. Black, Georg Thieme Verlag,
Stuttgart, New York, 2005, vol. 15, pp. 285–387; (b)
T. Boisse, B. Rigo, R. Millet and J. P. Henichart,
Tetrahedron, 2007, 63, 10511; (c) L. Chen, Y. L. Zhao,
Q. Liu, C. Cheng and C. R. Piao, J. Org. Chem., 2007, 72,
9259; (d) W. Pan, D. Dong, K. Wang, J. Zhang, R. Wu,
D. Xiang and Q. Liu, Org. Lett., 2007, 9, 2421; (e) T. H. Tsai,
W. H. Chung, J. K. Chang, R. T. Hsu and N. C. Chang,
Tetrahedron, 2007, 63, 9825; (f) H. Imase, K. Noguchi,
M. Hirano and K. Tanaka, Org. Lett., 2008, 10, 3563; (g)
J. Liu, D. Liang, M. Wang and Q. Liu, Synthesis, 2008, 3633;
(h) D. Xiang, K. Wang, Y. Liang, G. Zhou and D. Dong, Org.
Lett., 2008, 10, 345; (i) R. Zhang, D. Zhang, Y. Guo,
G. Zhou, Z. Jiang and D. Dong, J. Org. Chem., 2008, 73,
9504; (j) A. B. Smith III, O. Atasoylu and D. C. Beshore,
Synlett, 2009, 2643; (k) X. W. Wang, H. F. Cui, H. F. Wang,
Y. Q. Yang, G. Zhao and S. Zhu, Tetrahedron, 2011, 67,
Conclusions
In summary, the present work showed new route for the effi-
cient synthesis of substituted 2-pyridones in milder condition at
ambient temperature in good to excellent yield. This route has
shown the advantage of oxidative aromatization over elimina-
tion of nitrile group (in previous works). We not only explored
the substrate scope by using symmetrical and unsymmetrical
ketones, but also rationalized the thermodynamic and kinetic
products from unsymmetrical ketones. Since, 2-pyridone core
containing nitrile group at position 3 is ubiquitous in biologi-
cally active molecules, dye stuffs and natural products, this
route is likely to nd widespread use in the synthesis of relevant
compounds.
44144 | RSC Adv., 2014, 4, 44141–44145
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