Pyridines pyridine-3,5-dicarboxylate

The most common reaction of this type is the cyclization of various derivatives of hydrazine and substituted hydrazines with pyridine o-dicarboxylic acids and related compounds. Reactions in which the acid derivative reacts directly with the hydrazine are dealt with as [4 + 2] reactions in Section 2.15.10.6.1. 

To a solution of methyl 3-oxobutanoate 127 (580 mg, 5 mmol) and l-methyl-2-methylthio-l//-imidazole-5-carboxaldehye 128 (390 mg, 2.5 mmol) in 5 mL of absolute methanol was added a solution of ammonium hydroxide (25%, 0.4 mL). The reaction was heated at reflux overnight before cooling to room temperature and removing the solvent. The crude product was purified by preparative TLC to afford 526 mg of dimethyl l,4-dihydro-2,6-dimethyl-4-(l-methyl-2-methylthio-5-imidazolyl)-3,5-pyridine-dicarboxylate 129 (60%) as a solid, mp = 200-201 °C (MeOH). 

The rate of polymer erosion in the presence of incorporated anhydride and release of an incorporated drug depends on the pK of the diacid formed by hydrolysis of the anhydride and its concentration in the matrix (20). This dependence is shown in Fig. 7 for 2,3-pyridine dicarboxylic anhydride and for phthaUc anhydride. In this study, methylene blue was used as a marker. The methylene blue release rate depends both on the pK and on the concentration of diacid hydrolysis product in the matrix. However, at anhydride concentrations greater than 2 wt%, the erosion rate reaches a limiting value and further increases in anhydride concentration have no effect on the rate of polymer hydrolysis. Presumably at that point Vj, the rate of water intrusion into the matrix, becomes rate limiting. 

Advantage has been taken of the electronic similarity of phthalates to pyridine dicarboxylates ... 

JMJD2 demethylases are inhibited by analogues of the cofactor 2-OG that include N-oxalylamino acids, pyridine dicarboxylates, and related bipyridyl derivatives. Other chemotypes that are also presumed to bind to the active-site Fe(II) include catechols, hydroxamic acids (including the clinically used HD AC inhibitor SAHA/Vorinostat), and tricarboxylic acid cycle intermediates, such as succinate and fumarate [59,62]. 

Systematic studies150,153 with CLX50, (7), decyl esters of pyridine monocarboxylic acids (8)-(10), and dipentyl esters of pyridine dicarboxylic acids (11)—(15) showed that extraction of Cu11 is strongly dependent on the activity of water and the total concentration of ionic and molecular species in the aqueous phase. For the monoesters, copper distribution is dependent on... 

Bouvier, C. Cote, G. Cierpiszewski, R. Szymanowski, J. Influence of salting-out effects temperature and the chemical structure of the extractant on the rate of copper(II) extraction from chloride media with dialkyl pyridine dicarboxylates. Solvent Extr. Ion Exch. 1998, 16, 1465-1492. 

The hydrolysis of esters by the nickel derivative (271) provided an early example of the use of a metal-capped cyclodextrin as a catalyst (shown here as its p-nitrophenyl acetate inclusion complex) (Breslow Overman, 1970 Breslow, 1971). The synthesis of this host involves the following steps (i) covalent binding of the pyridine dicarboxylic acid moiety to cyclodextrin, (ii) coordination of Ni(n) to this species, and (iii)... 

A related geometry results from the use217 of 2,6-pyridine dicarboxylate in Ph2SnC7H3N04-H20. The two phenyl groups are at normal distances and trans (CSnC = 172°). The tridentate ligand occupies three sites in the equatorial plane and the coordinated... 

At negative potentials in alkaline solutions, adsorbed NA retains K+ ions, as demonstrated by Auger spectroscopy, Figure 5-B. This retention of K+ ions is due to interaction of K+ with the pendant carboxylate moiety and greatly exceeds the amounts expected simply from diffuse double-layer interactions. Potential-dependence of K+ retention is essentially absent for compounds incapable of potential-dependent carboxylate pendancy (pyridine, picolinic acid, isonicotinic acid and 2,6-pyridine dicarboxylic acid). 

Shown in Figure 6-A are EELS spectra of the entire series of pyridine carboxylic acids and diacids adsorbed at Pt(lll) from acidic solutions at negative electrode potential. Under these conditions all of the meta and para pyridine carboxylic acids and diacids exhibit prominent 0-H vibrations (OH/CH peak ratio near unity). In contrast, at positive potentials only the para-carboxylic acids display pronounced 0-H vibrations, Figure 6-B. All of the 0-H vibrations are absent under alkaline conditions, Figure 6-C. This situation is illustrated by the reactions of adsorbed 3,4-pyridine dicarboxylic acid ... 

Catalytic groups other than imidazole have been covalently linked to cycloamyloses. Breslow and Overman 14) bound a pyridine dicarboxylic acid group to a secondary hydroxyl by means of the m-nitrophenyl ester. When this group is chelated to pyridine carboxaldoxime through Ni " ", an... 

More advanced semiempirical molecular orbital methods have also been used in this respect in modeling, e.g., the structure of a diphosphonium extractant in the gas phase, and then the percentage extraction of zinc ion-pair complexes was correlated with the calculated energy of association of the ion pairs [29]. Semiempirical SCF calculations, used to study structure, conformational changes and hydration of hydroxyoximes as extractants of copper, appeared helpful in interpreting their interfacial activity and the rate of extraction [30]. Similar (PM3, ZINDO) methods were also used to model the structure of some commercial extractants (pyridine dicarboxylates, pyridyloctanoates, jS-diketones, hydroxyoximes), as well as the effects of their hydration and association with modifiers (alcohols, )S-diketones) on their thermodynamic and interfacial activity [31 33]. In addition, the structure of copper complexes with these extractants was calculated [32]. 

Figure 7.5 Water-soluble MSPs, based on a 2,6-pyridine dicarboxylate end-capped oligo(ethylene oxide) ditopic monomer (2a and 2b) and Zn ions prepared by Vermonden and coworkers (2003).

A good example of template copolycondensation has been described by Ogata et al Copolycondensation of 2,6-dimethyl pyridine dicarboxylate and dimethyl adipate with hexamethylene diamine was carried out in the presence of polysaccharide - Pullulane (mol. weight 30,000) used as a template. The reaction was carried out in DMSO at 60 C. It was found that the content of 2,6-dimethyl pyridine dicarboxylate units in the copolyamide, determined by NMR analysis, increased in the presence of Pullulane in comparison with the amount obtained in the absence of the template. This effect can be explained by preferential adsorption by the template of monomer having pyridine groups in comparison with the adsorption of dimethyl adipate. A set of experiments was carried out under the same conditions, but in the presence of poly(acrylonitrile) instead of Pullulane. The composition of copolyamides was the same as in copolycondensation without the template. 

Many other compounds are presendy in use a 1993 database search showed 27 active ingredients in 212 products registered by the U.S. EPA for human use as repellents or feeding depressants, including octyl bicycloheptene dicarboxamide (lV-2-ethylhexylbicyclo[2.2.1]-5-hepten-2,3-dicarboxamide), dipropyl isocinchomeronate (2,5-pyridine dicarboxylic acid, dipropyl ester), dimethyl phthalate, oil of citronella, cedarwood oil, pyrethrins, and pine tar oil (2). Repellent—toxicant or biting depressant systems are available which are reasonably comfortable for the user and can protect completely against a number of pests for an extended period of time (2). 

It may also be obtained by heating quinolinic acid 3 and certain other pyridine dicarboxylic acids.2 The nitrile has been prepared by heating sodium /3-pyridinesulfonate with potassium cyanide.4... 

SCHEME 8 A STEPWISE ROUTE TO UNSYMMETRICAL MACROCYCLES. WITH 2,6-PYRIDINE DICARBOXYLIC ACID DICHLORIDE BUILDING BLOCK 17 IS FORMED WHICH IS PREORGANIZED FOR MACROCYCLIZATION AND THUS GIVES HIGHER YIELDS OF MACROCYCLE 18 AS COMPARED TO 13. THE INSET SHOWS THE HYDROGEN BONDING PATTERN IN THE PYRIDINE BUILDING BLOCKS AND THE EFFECTS IT HAS ON CONFORMATIONAL EQUILIBRIA AND... 

AND ITS LARGER OCTALACTAM ANALOGUE 26, WHEN THE REACTION SEQUENCE SHOWN IN SCHEME 8 IS REVERSED AND EXTENDED DIAMINE 25 IS REACTED WITH 2,6-PYRIDINE DICARBOXYLIC ACID DICHLORIDE. 

A molecule with an even more spectacular topology was obtained when extended diamine 13 was reacted with 2,6-pyridine dicarboxylic acid dichloride. This was just a reversal of the order of the reaction steps in Figure 3. As well as the expected tetralactam macrocycle, its larger analogue octalactam wheel and a knot were formed [15], It was very surprising that a knot which bears three crossing points in its molecular... 

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