19621-92-2Relevant articles and documents
Photochemistry of the three carboxypyridines in water: A pH dependent reaction
Rollet, Florence,Richard, Claire,Pilichowski, Jean-Francois,Aboab, Bettina
, p. 2253 - 2261 (2004)
The photochemistry of ortho, meta and para-carboxypyridines (pK a1 = 1.0-2.1 and pKa1 = 4.7-5.3) in aqueous medium was studied by laser-flash photolysis and product studies. At pH a1, hydroxylated compounds are produced with low quantum yields. Within the pH range 4-7, ortho and meta isomers undergo dimerization together with decarboxylation with a quantum yield showing a very sharp maximum around pKa2 (φmax = 0.09 and 0.01, respectively) while the para isomer is photostable. End-of-pulse transients assigned to triplet states were detected by laser-flash photolysis at pH a1 and pH > 4. Additionally, the carboxypyridinyl radicals were detected as secondary intermediates at pH a1 and 4 a1. This is in favour of an electron transfer reaction between triplet and starting compound producing a charge transfer species. The radical anion would escape as carboxypyridinyl radical while the radical cation may add water at pH a1 yielding the OH-adduct radical or may undergo decarboxylation at pH > 4. The high quantum yield of phototransformation of the ortho isomer at pH > 4 is due to an easy decarboxylation process. A reaction scheme is proposed accounting for the dependences of φ on both the pH and the carboxypyridines concentration. This study points out the distinct pattern of reactivity of carboxypyridines depending on the ionisation state of starting compounds and isomeric substitution.
Infrared spectrum, molecular structure and theoretical calculation of 2-pyridone-6-carboxylic acid
Arslan,?engül,Aygün,Karadayi,Bayari, S. Haman
, p. 76 - 83 (2007)
The X-ray and infrared spectroscopic analysis of 2-pyridone-6-carboxylic acid are reported. The crystals of investigated molecule belong to P21/c of the monoclinic system, a = 11.714 ?, b = 3.7088?, c = 18.223? and β = 123.71°. The molecule is found in the ketonic form. Comprehensive studies of the molecular structures and vibrational frequencies and infrared intensities of the molecule have been performed by using Hartree-Fock, density functional B3LYP and second-order Moller-Plesset MP2 methods with the 6-31G+(d, p) basis set. The calculated geometrical parameters of investigated molecule in gas phase were compared with the experimental X-ray data.
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Boyer,Morgan
, p. 919,921 (1961)
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Preparation of 6-Oxo-1,6-dihydropyridine-2-carboxylic Acid by Microbial Hydroxylation of Pyridine-2-carboxylic acid
Kiener, Andreas,Gloeckler, Rainer,Heinzmann, Klaus
, p. 1201 - 1202 (2007/10/02)
Alcaligenes faecalis (DSM 6269) grown on pyridine-2-carboxylic acid induced regiospecific hydroxylation of the latter to 6-oxo-1,6-dihydropyridine-2-carboxylic acid on a preparative scale.