The reaction of aromatic aldehyde, malononitrile and 1,3-cyclohexanediones in water in the presence of triethylbenzyl-ammonium chloride (TEBA) provides an efficient access to 3-cyano-substituted 2-amino-4-aryl-4,6,7,8-tetrahydro-5H-1-benzopyran-5-ones.
(a) AnastasP.T., and WarnerJ. C., Green Chemistry – Theory and Practice, Oxford University Press, 1998.
2.
AnastasP.T., and WilliamsonT. C., Green Chemistry – Frontiers in Benign Syntheses and Processes, Oxford University Press, 1998.
3.
RajappaS., Emerging Eco-Friendly Alternatives for the Fine Chemical Industries; Sevak, Mumbai, 2000.
4.
(a) LiC.J., and ChanT. H., Organic Reactions in Aqueous Media; Wiley: New York, 1997.
5.
GriecoP.A., Organic Synthesis in Water, Kluwer Academic, Dordrecht, The Netherlands, 1997.
6.
(a) LiC.J., Chem. Rev., 1993, 93, 2023.
7.
LunbineauA., AugeJ., and QueneauY., Synthesis, 1994, 741.
8.
ChanT.H., and IsaacM. B., Pure Appl. Chem., 1996, 68, 919.
9.
For recent reviews on potassium channel openers, see: (a) PoyserR.H., and HamiltonT. C., Drugs of the Future, 1994, 19, 39.
10.
EmpfieldJ.R., and RussellK., Annu. Rep. Med. Chem., 1996, 30, 81.
11.
PirotteB., FontaineJ., and LebrunP., Curr. Med. Chem., 1995, 2, 573.
12.
AtwalK.S., Curr. Med. Chem., 1996, 3, 27; (e); J.M. Evans, T.C. Hamilton, S.D. Longman and G. Stemp, Potassium Channels and their Modulators: From Synthesis to Clinical Experience, Taylor & Francis, 1996.
13.
DarbarwarM., and SundarmurthyV., Synthesis, 1982, 337.
14.
GhosalS., MurugandamV., MukhopadhyayB., and BhattacharyaS., Ind. J. Chem., 1997, 36B, 596.
15.
(a) O'CallaghanC.N., and McMurryT. B. H., J. Chem. Res. (S), 1995, 214. (b) S. Hatakeyama, N. Ochi, H. Numata and S. Takano, J. Chem. Soc., Chem. Commun., 1998, 1202.
16.
KuthanJ., SebekP., and BohmS., Adv. Heterocyclic Chem., 1995, 62, 19.