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A CONVENIENT HANTZSCH SYNTHESIS OF 1,4-DIHYDROPYRIDINES USING TETRAETHYL ORTHOSILICATE

2003; De Gruyter; Volume: 9; Issue: 4 Linguagem: Inglês

10.1515/hc.2003.9.4.385

2191-0197

Mladen Litvić, Ivica Cepanec, Vladimir Vinković,

Synthesis and Characterization of Heterocyclic Compounds

Hantzsch dihydropyridine synthesis using tetraethyl orthosilicate as a water scavenger is described.With this method reaction time was drastically shortened in comparison with conventional methods.Generally, the obtained yields were good or excellent.Steric and electronic effect of different substituents on the yield and reaction time is studied.From the obtained results the plausible reaction mechanisms is proposed.1,4-Dihydropyridines (1,4-DHPs) are very important class of compounds because of their pharmacological activity as a calcium antagonist (1) or agonist.The 1,4-DHPs antagonists cause vasorelaxation by blocking voltage-operated calcium channel in smooth muscle cells and also by increasing NO release from the intact endothelium (2).Nifedipine 1 (3) as a first representative of these drugs was marketed in 1975.by Bayer AG.Since then a lot of new biologically active substances from 1,4-DHPs class appeared (4).Some of these compounds are characterized by larger bioavailability or greater tissue selectivity.To this day, 1,4-DHPs are still the most potent group of calcium channel blocker and their best seller members are nicardipine 2 (5), amlodipine 3 (6) and still nifedipine.