R
SYNTHETIC COMMUNICATIONSV
7
Acknowledgments
The authors gratefully acknowledge National Institute of Technology (NITW), Warangal and the
Ministry of Human Resource Development (MHRD), India, for Senior Research Fellowship.
References
[1] Anastas, P. T.; Williamson, T. C. Green Chemistry: Frontiers in Chemical Synthesis and
Processes, Edn Oxford University Press: Oxford, 1998. pp. 364þxvii
[2] Anastas, P.; Williamson, T. C. Green Chemistry: Theory and Practice. Oxford University
Press: Oxford. 1998. pp. 135þxi
[3] Anastas, P. T.; Kirchhoff, M. M. Origins, Current Status, and Future Challenges of Green
Chemistry. Acc. Chem. Res. 2002, 35, 686.
[4] Bhosle, M. R.; Khillare, L. D.; Dhumal, S. T.; Man, R. A. A Facile Synthesis of 6-Amino-
2H, 4H-Pyrano[2,3-c]Pyrazole-5-Carbonitriles in Deep Eutectic Solvent. Chin. Chem. Lett
2016, 27, 370–374.
[5] Zou, Y.; Wu, H.; Hu, Y.; Liu, H.; Zhao, X.; Ji, H.; Shi, D. A Novel and environment-
friendly method for preparing dihydropyrano[2,3-c]pyrazoles in water under ultrasound
irradiation. Ultrason. Sonochem. 2011, 18, 708–712.
[6] Zonouz, A. M.; Eskandari, I.; Khavasi, H. R. A Green and Convenient Approach for the
Synthesis of Methyl 6-Amino-5-Cyano-4-Aryl-2,4-Dihydropyrano[2,3-c]Pyrazole-3-
Carboxylates via a One-Pot, Multi-Component Reaction in Water. Tetrahedron. Lett.
2012, 53, 5519–5522.
[7] Nishtala, V. B.; Nanubolu, J. B.; Basavoju, S. Ultrasound-Assisted Rapid and Efficient
One-Pot Synthesis of Furanyl Spirooxindolo and Spiroquinoxalinopyrrolizidines by 1,3-
Dipolar Cycloaddition: A Green Protocol. Res. Chem. Intermed. 2017, 43, 1365–1381.
[8] Mecadon, H.; Rohman, Md, R.; Rajbangshi, M.; Myrboh, B. c-Alumina as a Recyclable
Catalyst for the Four-Component Synthesis of 6-Amino-4-Alkyl/Aryl-3-Methyl-2,4-
Dihydropyrano[2,3-c]Pyrazole-5-Carbonitriles in Aqueous Medium. Tetrahedron Lett.
2011, 52, 2523–2525.
[9] Mecadon, H.; Rohman, Md, R.; Harbangar, I.; Laloo, B. M.; Kharkongor, I.; Rajbangshi,
M.; Myrboh, B. l-Proline as an Efficicent Catalyst for the Multi-Component Synthesis of
6-Amino-4-Alkyl/Aryl-3-Methyl-2,4-Dihydropyrano[2,3-c]Pyrazole-5-Carbonitriles in Water.
Tetrahedron Lett 2011, 52, 3228–3231.
[10] Brahmachari, G.; Banerjee, B. Facile and One-Pot Access to Diverse and Densely
Functionalized 2-Amino-3-Cyano-4 H -Pyrans and Pyran-Annulated Heterocyclic
Scaffolds via an Eco-Friendly Multicomponent Reaction at Room Temperature Using
Urea as a Novel Organo-Catalyst. ACS Sustainable. Chem. Eng. 2014, 2, 411–422.
[11] Zou, Y.; Hu, Y.; Liu, H.; Shi, D. Rapid and Efficient Ultrasound-Assisted Method for the
Combinatorial Synthesis of Spiro[indoline-3,40-pyrano[2,3-c]pyrazole] Derivatives. ACS
Comb. Sci 2012, 14, 38–43.
[12] Bihani, M.; Bora, P. P.; Bez, G.; Askari, H. Amberlyst A21 Catalyzed Chromatography-
Free Method for Multicomponent Synthesis of Dihydropyrano[2,3-c]Pyrazoles in Ethanol.
ACS Sustainable. Chem. Eng. 2013, 1, 440–447.
[13] (a) Smith, W. P.; Sollis, L. S.; Howes, D. P.; Cherry, P. C.; Starkey, I. D.; Cobley, K. N.;
Weston, H.; Scicinski, J.; Merritt, A.; Whittington, A.; et al. Dihydropyrancarboxamides
Related to Zanamivir: A New Series of Inhibitors of Influenza Virus Sialidases.
1. Discovery, Synthesis, Biological Activity, and Structure-Activity Relationships of
4-Guanidino- and 4-Amino-4H-Pyran-6-Carboxamides. J. Med. Chem. 1998, 41, 787–797.
(b) Mazaahir, K.; Shilpi, S.; Khalilur, R. K.; Sharanjit, S. T. Aqua mediated synthesis of
substituted 2-amino-4H-chromenes and in vitro study as antibacterial agents. Bioorg. Med.
Chem. Lett 2005, 15, 4295–4298.