Pyridinecarboxylic acids and

Synthesis of acylpyridines, pyridinecarboxylic acids and their derivatives 98KGS1013. 

The appropriateness of using of microwave-assisted organic synthesis to obtain pyridinecarboxylic acids and pyrimidinecarboxylic acids was also described in [202]. The application of microwave irradiation reduces significantly the reaction time from 2 h to 10 min, increases yields of the target compounds and also allows high-boiling and hard-to-remove solvents (DMF and acetic acid) to be replaced by ethanol. 

The pyrazinecarboxylic acids have properties similar to the pyridinecarboxylic acids and aromatic carboxylic acids in general. The pKa of pyrazine-2-carboxylic acid is 2.92 it is thus considerably stronger than pyridine-2-carboxylic acid (pff0 5.52), and comparable in acidic strength to pyridazine-3-carboxylic acid (pKa 3.0). The pKa values of pyrazine-2,3-dicarboxylic acid are 0.9 and 3.57.231 Pyrazinecarboxylic acids form colored salts with Fe11 ions and they are readily esterified and decarboxylated. 

Sanchez. J.P.. Mich, T.E. and Huang, G.G.. An efficient synthesis of 6-formyl-l,2-dihydro-2-oxo-3-pyridinecarboxylic acid and some carbonyl derivatives of it and its 6-acetyl homologue, J. Heterocyd. Chem.. 31. 297, 1994. 

The involvement of zinc in nicotinamide-based hydride-transfer reactions has led to numerous studies of Group IIB complexes of pyridine carboxylic acid derivatives. Cadmium complexes of 2-pyridmecarboxylic acid, 3-pyridinecarboxylic acid and 3-pyridinecarboxamide have been reported. The crystal structure of [Cd(HC02)2L2(H20)2] (L = 3-pyridinecarboxamide) has also been described the metal is in an octahedral environment in which the amide acts as a monodentate N donor. ... 

Solvating reagents such as neutral compounds (e.g., ethers, ketones, alcohols, and esters of carboxylic acids, alkyl phosphates, phosphonates, phos-phinates, phosphine oxides, and phosphine sulfides) and also esters of pyridinecarboxylic acids and certain benzimidazole derivatives that have electron-withdrawing substituents form solvates with extracted neutral species. For example, dialkylpyridine-3,5-carboxylates extract Cu(II) at pH 3 from concentrated chloride solutions ... 

Separation schemes for pyridinecarboxylic acids and nicotinic and isonicotinic acids are reported. Paper chromatography and gas chromatography of pyridinecarboxylic acids have been discussed, and the crystal structures of picolinic acid hydrochloride and picolinamide have been described. 

Niacin and niacinamide (also known as nicotinic acid and nicotinamide, respectively) or vitamin B3, chemically 3-pyridinecarboxylic acid and 3-pyridinecarboxamide, are able to form various cadmium complexes with known crystal and molecular structures. In order to rationalize the analysis, hereafter the complexes have been differentiated according to the ligand and, within each case, we have only considered the most relevant structures. 

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