General experimental methods and detailed procedures for the synthesis of propynone 12b, Bohlmann–Rahtz pyridine 2b and Hantzsch dihydropyridines 15a, 15b and 15c.
N2 - The reaction of anilines, benzaldehydes, and ethyl 3,3-diethoxypropionate in the presence of Yb(OTf)3 proceeded under mild reaction conditions to give dihydropyridines (DHPs). We have found that the reaction depended on the solvent and the DHPs were obtained selectively in 1,4-dioxane as a solvent. Various 2,6-unsubstituted DHPs were synthesized in one pot in satisfactory yields.
Ytterbium-catalyzed synthesis of dihydropyridines
An efficient and straightforward method for the synthesis of polycyclic ring systems with a central 2-azabicyclo[2.2.2]octane unit is developed. The process is based on [4+2]-cycloaddition reactions that are performed with N-protonated 2-azabutadiene intermediates as heterodienes, generated from 4,4-disubstituted -silyl 1,4-dihydropyridines. As dienophiles, cyclopentadiene for the intermolecular cycloaddition and an allyl moiety already attached to the 4,4-disubstituted 1,4-dihydropyridines for the intramolecular variant, are used.
An Efficient Synthesis of 4-Aryl-1,4-dihydropyridines …
Chapter Three describes a mild and efficient protocol for the synthesis of 1,4-dihydropyridines via four component reactions of aromatic aldehydes, dimedone, ethyl acetoacetate or methyl acetoacetate and ammonium acetate using Fe(ClO4)3/SiO2.
Adiro Drug Information, Indications & Other Medicaments …
Objective(s) Four novel losartan analogues 5a-d were synthesized by connecting a dihydropyridine nucleus to imidazole ring. The effects of 5a and 5b on angiotensin receptors (AT1) and L-type calcium channels were investigated on isolated rat aorta. Materials and Methods Aortic rings were pre-contracted with 1 µM Angiotensin II or 80 mM KCl and relaxant effects of losartan, nifedipine, 5a and 5b were evaluated by cumulative addition of these drugs to the bath solution. Results The results showed that compounds 5a and 5b have both L-type calcium channel and AT1 receptor blocking activity. Their effects on AT1 receptors are 1000 and 100,000 times more than losartan respectively. The activity of compound 5b on L-type calcium channel is significantly less than nifedipine but compound 5a has comparable effect with nifedipine. Conclusion Finally we concluded that these two new Compounds can be potential candidates to be used as effective antihypertensive agents.
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N2 - We have successfully synthesized 3,4,5-substituted 1,4-dihydropyridines (1,4-DHPs) from amine hydrochloride salts, aldehydes, and acetals in good yields without the addition of a catalyst. The synthesized 1,4-DHPs exhibit various wavelengths of fluorescence, which could be tuned by changing the substituents at the 3- and 5-positions of the 1,4-DHPs.
Pyridine synthesis - Organic chemistry
An efficient and general method for the synthesis of 1,4-dihydropyridines and pyridines based on a lithiation/isomerization/intramolecular carbolithiation sequence is reported. This procedure provides an efficient, divergent, and straightforward entry to a wide range of polysubstituted dihydropyridines and pyridines starting from readily available -allyl-ynamides.