2110-14-7Relevant articles and documents
Synthesis, crystal structure and spectral properties of diammonium dihydrogen N-(methylene-2-pyridine)-N,N,-di-(methylenephosphonate)
Janicki, Rafa?
, p. 35 - 41 (2013)
In this paper synthesis, crystal structure and spectral properties of a new, N-(methylene-2-pyridine)-N,N,-di-(methylenephosphonic) acid (hereinafter IV) are reported. The X-ray structure analysis revealed that in crystal of the ammonium dihydrogen N-(methylene-2-pyridine)-N,N-di(methylenephosphonate) (hereinafter V) two of the six oxygen atoms from phosphonic groups are protonated and form strong hydrogen bonds, moreover the N(pyridine) and N(amino) atoms are deprotonated. The acid-base properties of studied compound in aqueous solution indicated that the dissociation constants pK1dis 0.70 ± 0.03 and pK2dis 0.98 ± 0.05 are very similar to that determined for nitrilotri(methylphosphonic) acid.
ISOXAZOLO-PYRIDAZINE DERIVATIVES
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, (2009/06/27)
The invention relates to isoxazolo-pyridazine compounds, in particular those of formula I as described above and to a pharmaceutically acceptable salts thereof, having affinity and selectivity for the GABA A α5 receptor binding site, their manufacture, pharmaceutical compositions containing them and their use as cognitive enhancers or for the treatment of cognitive disorders like Alzheimer's disease.
Effect of structure in benzaldehyde oximes on the formation of aldehydes and nitriles under photoinduced electron-transfer conditions
De Lijser, H.J. Peter,Hsu, Susan,Marquez, Bernadette V.,Park, Adriana,Sanguantrakun, Nawaporn,Sawyer, Jody R.
, p. 7785 - 7792 (2007/10/03)
(Chemical Equation Presented) The mechanistic aspects of the photosensitized reactions of a series of benzaldehyde oximes (1a-o) were studied by steady-state (product studies) and laser flash photolysis methods. Nanosecond laser flash photolysis studies have shown that the reaction of the oxime with triplet chloranil (3CA) proceeds via an electron-transfer mechanism provided the free energy for electron transfer (ΔGET) is favorable; typically, the oxidation potential of the oxime should be below 2.0 V. Substituted benzaldehyde oximes with oxidation potentials greater than 2.0 V quench 3CA at rates that are independent of the substituent and the oxidation potential. The most likely mechanism under these conditions is a hydrogen atom transfer mechanism as this reaction should be dependent on the O-H bond strength only, which is virtually the same for all oximes. Product studies have shown that aldoximes feact to give both the corresponding aldehyde and the nitrile. The important intermediate in the aldehyde pathway is the iminoxyl radical, which is formed via an electron transfer-proton transfer (ET-PT) sequence (for oximes with low oxidation potentials) or via a hydrogen atom transfer (HAT) pathway (for oximes with larger oxidation potentials). The nitriles are proposed to result from intermediate iminoyl radicals, which can be formed via direct hydrogen atom abstraction or via an electron-transfer-proton- transfer sequence. The experimental data seems to support the direct hydrogen atom abstraction as evidenced by the break in linearity in the plot of the quenching rates against the oxidation potential, which suggests a change in mechanism. The nitrile product is favored when electron-accepting substituents are present on the benzene ring of the benzaldehyde oximes or when the hydroxyl hydrogen atom is unavailable for abstraction. The latter is the case in pyridine-2-carboxaldoxime (2), where a strong intramolecular hydrogen bond is formed. Other molecules that form weaker intramolecular hydrogen bonds such as 2-furaldehyde oxime (3) and thiophene-2-carboxaldoxime (4) tend to yield increasing amounts of aldehyde.
Metalloenzyme Models. Divalent Metal Ion Catalyzed Hydrolysis of p-Nitrophenyl Picolinate in the Presence of Imidazoles and Pyridines Having Hydroxyl Groups in Their Side Chains
Ogino, Kenji,Shindo, Katsuhiko,Minami, Tooru,Tagaki, Waichiro,Eiki, Toshio
, p. 1101 - 1106 (2007/10/02)
Rate constants for hydrolysis of p-nitrophenyl picolinate at 25 deg C in the pH range 6.5-8.5 were measured in the absence and presence of divalent metal ions (Ni(II), Zn(II), Co(II), Ca, Mg) and substituted imidazoles or pyridines as ligands having alcoholic hydroxyl groups in their side chains. In the presence of either metal ion or ligand, the rate is slow and the pseudo-first-order rate constant (kobsd) increases linearly in a first-order manner with respect to the concentration of metal ion or ligand until it gives the second-order rate constant, kM or kL, respectively. In the presence of both a metal ion (Ni(II) or Zn(II)) and a ligand, rate increase is remarkable for some ligands and the increase in kobsd values constructs saturation curves with respect to increase in either metal ion or ligand concentration. The saturation curves were analyzed based upon rate equations formulated by assuming the formation of 1:1 complex of metal ion and ligands as the catalyst, leading to evaluation of the association constant K for complexes and the second-order rate constant kc for the reaction of complex with substrate. Values of kobsd, kc, and K are dependent greatly upon the structure of ligands and pH. The ligands complexed with Zn(II) ion appear to be simple but highly active models of hydrolytic metalloenzymes.
