some 3, 5-diacyl or 3,5-diester 1,4-dihydropyridines were oxidized to the corresponding pyridine derivatives using hydrogen peroxide in aqueous ethanol in the presence of potassium bromide and acetic acid as the catalysts. the reaction was carried out in ethanol and products were isolated in high to excellent yields. however, oxidation of 3,5-diacetyl 1,4-dihydropyridines is slower than 3,5-die...

Parathyroid cells express Ca2+ -conducting currents that are activated by raising the extracellular Ca2+ concentration ([Ca2+]o). We investigated the sensitivity of these currents to dihydropyridines, the expression of voltage-dependent Ca(2+) channel (VDCC) subunits, and the effects of dihydropyridines on the intracellular free [Ca2+] ([Ca2+]i) and secretion in these cells. Dihydropyridine cha...

We have investigated the mechanisms of blockade of calcium channel current by the dihydropyridines, e.g. nisoldipine, nitrendipine, and nicardipine. Membrane current was recorded in isolated calf Purkinje fibers using a two-microelectrode voltage-clamp technique, and voltage protocols were designed to identify voltage- and use-dependent block by these compounds systematically. Our results show ...

Some 3, 5-diacyl or 3,5-diester 1,4-dihydropyridines were oxidized to the corresponding pyridine derivatives using hydrogen peroxide in aqueous ethanol in the presence of potassium bromide and acetic acid as the catalysts. The reaction was carried out in ethanol and products were isolated in high to excellent yields. However, oxidation of 3,5-diacetyl 1,4-dihydropyridines is slower than 3,5-die...

A series of dihydropyridines were identified that have an effect on the accumulation of tau, an important target in Alzheimer's disease. The dihydropyridine collection was expanded using the Hantzsch multicomponent reaction to develop preliminary structure-activity relationships.

Efflux of cytotoxic agents mediated by P-glycoprotein is believed to be an important mechanism of multidrug resistance, which remains a serious limitation to successful chemotherapy in cancers such as metastatic breast cancer. A series of 4-aryl-1,4-dihydropyridines and corresponding aromatized 4-arylpyridines have been synthesized based on structure modifications of niguldipine to enhance mult...

An eco-friendly "on-water" protocol for efficient catalyst-free synthesis of the Hantzsch dihydropyridines from aryl, heteroaryl, alkyl, and vinylogous aldehydes has been developed with minimum auxiliary substances, toxic reagents, organic solvents, and disposal problems.

Calcium channel blockers are widely used antihypertensives. Mineralocorticoid receptor antagonists are also used to treat hypertension and heart failure. We report here that a number of widely used dihydropyridine class calcium channel blockers are able to inhibit aldosterone-induced activation of mineralocorticoid receptor. These dihydropyridines varied in the extent of their effect on mineral...

The reactions of sec-aminodienyl esters 3 with acetylacetone (4) afforded N-alkyl 3-acetyl-4-methoxycarbonylmethyl-2-methyl-1,4-dihydropyridines 5 and enamines 6, providing a new azaelectrocyclization reaction.

A facile and convenient protocol was developed for the fast (2.5-3.5 h) and high yielding (70-90%) synthesis of fused 1,4-dihydropyridines from dimedone in the presence of HY-zeolite as an efficient recyclable heterogeneous catalyst.