Pyrans and Pyrano[2, 3-c]pyrazole Derivatives
2119
benzon-[b]-pyran derivatives catalyzed by KF-alumina. Synth. Commun. 2003, 33,
119; (c) Wang, X. S.; Shi, D. Q.; Rong, L. C.; Yao, C. S.; Dai, G. Y. Synthesis and
crystal structure of 3-methyl-5-cyano-6-amino-1-phenyl-4-(3,4-dimethoxyphe-
nyl)-1,4-dihydropyrano[2,3-c]pyrazole. Jie Gou Hua Xue 2003, 22 (3), 331;
(d) Ismail, Z. H.; Aly, G. M.; El-Degwi, M. S.; Heiba, H. I.; Ghorab, M. M.
Synthesis and insecticidal activity of some new pyranopyrazoles, pyrazolopyrano-
pyrimidines, and pyrazolopyranopyridines. Egyptian. J. Biotechnol. 2003, 13, 73;
(e) Ipsita, D.; Pulak, J. B. Sodium bromide catalysed one-pot synthesis of tetrahy-
drobenzo[b]pyrans via a three-component cyclocondensation under microwave
irradiation and solvent-free conditions. Tetrahedron Lett. 2004, 45, 8625.
9. (a) Tu, S. J.; Miao, C. B.; Gao, Y.; Feng, Y. J.; Feng, J. G. Microwave-prompted
reaction of cinnamonitrile derivatives with 5,5-dimethyl-1,3-cyclohexanedione.
Chin. J. Chem. 2002, 20, 703; (b) Zhou, J. F.; Tu, T. J.; Gao, Y.; Ji, M. One pot
synthesis of pyrans and pyrano[2,3-c]pyrazole derivatives under microwave
irradiation. Chin. J. Org. Chem. 2001, 21 (10), 742; (c) Tu, S. J.; Gao, Y.;
Guo, C.; Shi, D. Q.; Lu, Z. S. A convenient synthesis of 2-amino-5,6,7,8-
tetrahydro-5-oxo-4-aryl-7,7-dimethyl-4H-benzo-[b]-pyran-3-carbonitrile under
microwave irradiation. Synth. Commun. 2002, 32 (14), 2137; (d) Zhou, J. F.;
Tu, S. J.; Zhu, H. Q.; Zhi, S. J. A facile one pot synthesis of pyrano[2,3-c]
pyrazole derivatives under microwave irradiation. Synth. Commun. 2002,
32 (21), 3363.
10. Li, J. T.; Xu, W. Z.; Yang, L. C.; Li, T. S. One-pot synthesis of 2-amino-4-aryl-3-
carbalkoxy-7,7-dimethyl-5,6,7,8-tetrahydro-benzo[b]pyran derivatives catalyzed
by KF/basic Al2O3 under ultrasound irradiation. Synth. Commun. 2004, 34, 4565.
11. (a) Jin, T. S.; Wang, A. Q.; Wang, X.; Zhang, J. S.; Li, T. S. A clean one-pot
synthesis of tetrahydrobenzo[b]pyran derivatives catalyzed by hexadecyltri-
menthylammonium bromide in aqueous media. Synlett. 2004, 871; (b) Jin, T. S.;
Wang, A. Q.; Cheng, Z. L.; Zhang, J. S.; Li, T. S. A clean and simple synthesis
of 6-amino-4-aryl-5-cyano-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazole
in water. Synth. Commun. 2005, 35, 137.
12. (a) Shi, D. Q.; Mou, J.; Zhuang, Q. Y.; Wang, X. S. One-pot synthesis of 2-amino-
4-aryl-5-oxo-5,6,7,8-tetrahydro-4H-1-benzopyran-3-carbonitriles in aqueous
media. J. Chem. Res. 2004, 12, 821; (b) Shi, D. Q.; Zhang, Z.; Zhuang, Q. Y.;
Tu, S. J.; Hu, H. W. Clean synthesis of 2-amino-3-cyano-4-aryl-7,7-dimethyl-5-
oxo-4H-5,6,7,8-tetra hydrobenzo[b]pyran in water. Chin. J. Org. Chem. 2003,
23 (8), 877; (c) Shi, D. Q.; Mou, J.; Zhuang, Q. Y.; Niu, L. H.; Wu, N.;
Wang, X. S. Three-component one-pot synthesis of 1,4-dihydropyranl [2,3-c]
pyrazloe derivatives in aqueous media. Synth. Commun. 2004, 34 (24), 4557.
13. Kaupp, G.; Naimi-Jamal, M. R.; Schmeyers, J. Solvent-free Knoevenagel conden-
sations and Michael additions in the solid state and in the melt with quantitative
yield. Tetrahedron 2003, 59, 3753.
14. He, L.; Tang, Z.; Cun, L. F.; Mi, A. Q.; Jiang, Y. Z.; Gong, L. Z. L-proline amide–
catalyzed direct asymmetric aldol reaction of aldehydes with chloroacetone-
Tetrahedron 2006, 62, 346.
15. Meghana, S. R.; Mahesh, K. P.; Swapnil, S. M.; Manikrao, M. S. An ionic liquid
influenced L-proline catalyzed asymmetric Michael addition of ketones to nitros-
tyrene. J. Mol. Catal. A 2005, 235, 267.
16. Sabitha, G.; Kumar, M. R.; Reddy, M. S. K.; Yadav, J. S.; Krishna, K. V. S. R.;
Kunwar, A. C. A D,L-proline catalyzed diastereoselective trimolecular conden-
sation: An approach to the one-pot synthesis of perhydrofuro[3,2-b]pyran-5-
ones. Tetrahedron Lett. 2005, 46, 1659.