Dihydropyr idines

Kantam ML, Ramani T, Chakrapani L, Choudary BM (2009) Synthesis of 1,4-dihydropyr-idine derivatives using nanocrystalline copper(II) oxide catalyst. Catal Commun 10 370-372... 

Mass spectrometric fragmentation of substituents and rings are presented in Table 14. Among further examples, enamine 184a shows (M — nitrophenyl) as the base peak, a behavior typical of 1,4-dihydropyr-idines (77LA1888). Tetrabrominated lactam 347 (see Scheme 78) gives a... 

Hyvonen Z, Plotniece A, Riene I et al (2000) Novel cationic amphiphilic 1,4-dihydropyr-idine derivatives for DNA delivery. Biochim Biophys Acta-Biomembranes 1509 451 -66... 

Ferry DR, Russell MA, Cullen MH. P-glycoprotein possesses a 1,4-dihydropyr-idine-selective drug acceptor site which is alloserically coupled to a vinca-alkaloid-selective binding site. Biochem Biophys Res Commun 1992 188(1 ) 44(M145. 

Among calcium antagonists, dihydropyr-idines with long half-lives are advantageous because short-acting drugs, which rapidly lower blood pressure, are prone to elicit reflex tachycardia. 

His main interests include organic chemistry, heterocyclic chemistry (quinolones, dihydropyr-idines, benzimidazoles, benzotriazoles, benzoselenadiazoles, bcnzothiadiazoles, glutaric acids, enol ethers), utilization of heterocyclic compounds in the organic synthesis, and molecular spectroscopy. 

In general only very electron-deficient double bonds will react spontaneously with 1,4-dihydropyr-idines. (This statement applies to nonenzymic chemistry enzymatically, as in LAD, NAD(P)H, with a lesser reduction potential than many of the 1,4-dihydropyridines used in abiotic reactions, reduces unactivated carbonyl groups.) Thiobenzophenone, quinone, maleic acid, and hexachloroacetone react spontaneously with simple dihydropyridines and undergo reduction (the carbon-carbon double bond of maleic anhydride is reduced). Trifluoroacetophenone will also often react spontaneously with 1,4-dihydro-pyridines. 

During their studies on the hydrogenation mechanism of quinolines, Zhou and coworkers found that the dehydroaromatization reactions of 1,4 dihydropyr idines (Hantzsch esters) could be realized using their catalytic system, and hydrogen gas was produced in this reaction [29]. Subsequently, they reported the... 

Pre- and postsynaptic elements, therefore, play a key role in excitation of the brain. We focus here on prototypes of a presynaptic and a postsynaptic element. As an example of a presynaptic element, we selected the dihydropyr-idine-sensitive calcium channel, a member of the superfamily of voltage-gated channel proteins. The most extensively studied membrane protein, the nicotinic cholinergic receptor, which belongs to the family of ligand-gated channels, is present in the postsynaptic membrane. These two examples are used to describe a strategy that aims to identify sequence-specific motifs that are responsible for the performance of unique functions and to outline an experimental approach to evaluate identified structural motifs. 

The easy specific reduction of 3-acylpyridinium salts giving stable 3-acyl-1,4-dihydropyridines using sodium dithionite is often quoted, because of its perceived relevance to nicotinamide coenzyme activity the mechanism involves addition of sulfur at C-4 as its first step, as shown below.1,4-Dihydropyridines are normally air-sensitive, easily rearomatised molecules the stability of 3-acyl-1,4-dihydropyr-idines is related to the conjugation between ring nitrogen and side-chain carbonyl group (see also Hantzsch synthesis, section 5.15.1.2). However, even simple pyridinium salts, provided the A-substituent is larger than propyl, or for example benzyl, can be reduced to 1,4-dihydropyridines with sodium dithionite. ... 

There are several methods for the preparatior of 4-oxo-l,4-dihydropyr-idine derivatives (74B597, 84CHEC(2)395, 96CHEC-II(5)167, 08CHEC-III (7)217). 

B/s-enaminones 52 with primary (hetero)arylamines were employed in a parallel solution-phase synthesis of a library of 22 1,4-dihydropyr-idine derivatives 53, while mono-enaminone 2 with amines produced substitution products 84. Two methods for 53 were developed (a) a one-step s5mthesis of DHPs 53 from fws-enaminones 52 (Method A) and (b) a two-step synthesis of DHPs 53 from the mono-enaminone 2 (Method B). 

ClgHi8N2O2, 2,6-Dimethyl-3,5-diacetyl-4-(p-pyridyl)-1,4-dihydropyr-idine, 43B, 303... 

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