Pyridine derivatives R 0380 3,4-trans-4-Aryl-3-(1-pyridinio)-1,2,3,4-tetrahydropyridine-6-thiolates -NewGroup of Potential Cardiotonic Drugs. -The title compounds are prepared by Michael reaction of N-acetonylpyridinium chloride (I) with 3-aryl-2-cyanothioacrylamides. Thiolate (VIa) shows cardiotonic activity comparable to that of milrinone, however at lower concentrations and lower toxicity. -(KRAUZE*, A.; VITOLINA, R.; GARALIENE, V.; SILE, L.; KLUSA, V.; DUBURS, G.; Eur.
Keywords: 1,4-dihydropyridines, hydrogen bond, one-pot multicomponent method, electrochemical oxidation, X-ray diffraction analysis.Nitriles of 2-alkylthio-4-aryl-1,4-dihydropyridine-3-carboxylic acids are of interest as potential antioxidants [1,2] that are also distinguished by cardiovascular [3,4] and hepatoprotective [5] activity.Continuing a study of the chemical and electrochemical properties of 2-alkylthio-1,4-dihydropyridines [4, 6] and methods for obtaining them [7,8], we have synthesized a series of novel 4-aryl-2-carbamoylmethylthio-5-ethoxycarbonyl-6-methyl-1,4-dihydropyridine-3-carboxylic acid nitriles 1, in which we varied the substituents on the 4-phenyl ring over a broad range. We carried out a comparative analysis of the capability for electrochemical oxidation of 2-alkylthio-4-aryl-5-ethoxycarbonyl-1,4-dihydropyridine-3-carboxylic acid nitriles 1 and 4 as a function of the electronic properties of the aryl substituent on the 4 position of the heterocycle and the 2-alkylthio substituent, since the corresponding values of the potentials quantitatively characterize the antioxidant properties of the compounds. The electrochemical oxidation data were used for a more targeted search for biologically active substances. _______ * Dedicated to Academician V. Minkin to show our appreciation for his contribution to organic chemistry and his wonderful humanity, remembering his collaboration with his colleagues from Riga. _________________________________________________________________________________________
Keywords: 2-(benzoylmethylsulfanyl)nicotinamide, 2,3-dihydro-7H-thiazolo[3,2-a]pyridine-8-carboxamide, N-methyl-2-(1,3-thiazol-2-yl)acetamide, 6-oxo-5-(thiazol-2-yl)-1,6-dihydropyridine-3-carbonitrile.Previously it was established that the one-pot condensation of benzylidenemalononitrile (1), N-methyl-2-thiocarbamoylacetamide (2b), piperidine 3a, and chloroacetone 4a resulted in N-methyl-3-hydroxy-3-methyl-2,3-dihydro-7H-thiazolo[3,2-a]pyridine-8-carboxamide (5) obtained in 82% yield (Scheme 1) [1].It was also proved that N-unsubstituted 3-hydroxy-3-phenyl-2,3-dihydro-7H-thiazolo[3,2-a]pyridine-8-carboxamide (6a) can be prepared both by the above mentioned one-pot multicomponent synthesis (yield 84%) [1] or by treatment of 1,4-dihydropyridine-6-thiolate 8a [2] with ω-bromoacetophenone 4b (yield 83%) [1].
Scheme 1Ph NC CN CSNH 2
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