One-Pot and Solvent-Free Synthesis of 1,4-Dihydropyridines and 3,4-Dihydropyrimidine-2-ones Using New Synthetic Recyclable Catalyst via Biginelli and Hantzsch Reactions
Pyridine dicarboxylic acid guanidine-cobalt complex (PDAG-Co) (3) catalyzes one-pot, three-component coupling of aldehydes, -dicarbonyl compounds, and ammonium acetate to afford the corresponding 1,4-dihydropyridines (1,4-DHPs) via Hantzsch reaction. 3,4-Dihydropyrimidine-2-ones (3,4-DHPMs) and their sulfur analogs are also synthesized under the same conditions via Biginelli condensation protocol. The catalyst is reusable at least five times, highly efficient, easily prepared, and used under mild reaction conditions. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) to view free supplemental file.
Synthesis of diethyl 4-substituted-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylates as a new series of inhibitors against yeast α-glucosidase
1,4-Dihydropyridine-3,5-dicarboxylate derivatives (1-25) were synthesized in high yields via Hantzsch reaction and evaluated for their a-glucosidase inhibitory activity. Compounds 1, 2, 6-8, 11, 13-15, and 23-25 showed a potent inhibitory activity against yeast alpha-glucosidase with IC50 values in the range of 35.0-273.7 mu M, when compared with the standard drug acarbose (IC50 = 937 +/- 1.60 mu M). Their structures were characterized by different spectroscopic techniques. The kinetics, selectivity, and toxicity studies on these compounds were also carried out. The kinetic studies on most active compounds 14 and 25 determined their modes of inhibition and dissociation constants K-i. Compound 14 was found to be a noncompetitive inhibitor with K-i = 25.0 +/- 0.06, while compound 25 was identified as a competitive inhibitor with K-i = 66.0 +/- 0.07 mu M. (C) 2015 Elsevier Masson SAS. All rights reserved.