A modified strategy for Pictet-Spengler reaction leading to the synthesis of imidazoquinoxalines on solid phase.
An alternative strategy for Pictet-Spengler reaction involving an N-1 linked aromatic amine of imidazole and aldehydes is described. This is in contrast to a typical Pictet-Spengler reaction, which involves an aliphatic amine attached to the carbon of an activated aromatic nucleus and an aldehyde. Our strategy commences with the nucleophilic replacement of fluorine in resin-bound o-fluoro-nitrobenzoic acid with mono- or disubstituted imidazole, followed by reduction of the nitro group to give an N1 linked aromatic amine of the resin-bound imidazole. This was subsequently treated with an aldehyde in toluene at 80 degrees C and then oxidized in the presence of DDQ to give resin-bound imidazoquinoxalines. Finally, acidolytic cleavage furnished the desired compounds in high yields and purities.
Kundu
Bijoy
B
Medicinal Chemistry Division, Central Drug Research Institute, Lucknow 226001, India.
Sawant
Devesh
D
Chhabra
Rahul
R
D020650:Combinatorial Chemistry Techniques / Q000379:methods*; D007093:Imidazoles / Q000737:chemistry*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D011810:Quinoxalines / Q000138:chemical synthesis* / Q000737:chemistry
D007093:Imidazoles; D011810:Quinoxalines