17260-79-6Relevant academic research and scientific papers
Structure Sensitivity of the Marcus λ for Hydride Transfer between NAD+ Analogues
Kreevoy, Maurice M.,Ostovic, Drazen,Lee, In-Sook Han,Binder, David A.,King, Gary W.
, p. 524 - 530 (2007/10/02)
Thirty-five rate constants, kij, for transfer of hydride between various pyridinium, quinilinium, acridinium, and phenantridinium ions spanning a range of over 10E11 in their equilibrium constants Kij and over 10E6 in kij
Regioselectivity and Kinetics of Hydride Transfer in Substituted 1-Benzyl-3-quinolinecarboxamide Redox Reactions
Romoff, Todd T.,Sampson, Nicole S.,Eikeren, Paul van
, p. 4454 - 4459 (2007/10/02)
A systematic study on the factors that affect the regioselectivity and rate of hydride transfer in systems involving 1-benzyl-4-methyl-3-quinolinecarboxamides as donors or acceptors is reported.The study reports two major findings: (1) Hydride transfers from borohydride or 1-propyl-1,4-dihydronicotinamide to 1-benzyl-4-methyl-3-quinolinecarboxamide cation display distinct regioselective patterns-borohydride results in hydride transfer to the 2-position of the acceptor and dihydronicotinamide results in hydride transfer to the 4-position of the acceptor. (2) Substitution of the 4-hydrogen by a methyl group on either the oxidant or reductant quinoline lowers the rate constants for hydride transfer by a factor of over 2000.When methyl replaces hydrogen in both the oxidant and reductant, the rate constant for hydride transfer is lowered by a factor of over 5 000 000.These observations are interpreted in terms of a two-step mechanism: (1) formation of a ?-complex between the oxidant and reductant stabilized by charge-transfer interactions and (2) rate-determining hydride transfer within the complex.
Reaction of NADH models with methylene blue
Engbersen, J. F. J.,Koudijs, A.,Plas, H. C. van der
, p. 131 - 138 (2007/10/02)
The NADH models, (1R)-1,4-dihydronicotinamide and (1R)-1,4-dihydroquinoline-3-carboxamide (1-4, R=X-benzyl or octyl), are readily oxidized by methylene blue (MB), yielding the corresponding pyridium ions and leuco-methylene blue (MBH).Under aerobic reaction conditions, molecular oxygen, present in the reaction solution, rapidly reoxidizes MBH to MB, thereby allowing the study of the oxidation of the NADH models under pseudo-first-order reaction conditions.In order to elucidate the mechanism of the oxidation of the NADH models by MB, the influence of the MB concentration, solvent and temperature has been studied as well as the effect of substituent variation in the benzyl group in a series of 1-(X-benzyl)-1,4-dihydronicotinamides (1a-f).For one of the model compounds, 1-benzyl-1,4-dihydronicotinamide (1a, BNAH), the primary and the secondary isotope effect and the temperature dependence of the kinetic isotope effect have been determined.It is concluded that oxidation of the NADH models by MB most likely proceeds by a rate-determining hydride transfer process via a linear, symmetrical transition-state structure.
Hydride Transfer and Oxyanion Addition Equilibria of NAD+ Analogues
Ostovic, Drazen,Lee, In-Sook Han,Roberts, Roger M. G.,Kreevoy, Maurice M.
, p. 4206 - 4211 (2007/10/02)
Equilibrium constants, K, have been determined for the reduction of 10-methylacridinium ion by 15 N-heterocyclic hydride donors: acridine, quinoline, pyridine, and phenanthridine derivatives.The solvent was a mixture of 2-propanol and water in the ratio 4 : 1 by volume.Reduction potentials have been estimated for the corresponding cations in aqueous solution by assuming that the K's would be the same and accepting -361 mV as the reduction potential of the 3-(aminocarbonyl)-1-benzylpyridinium ion.These reduction potentials span 430 mV.Values of pKR have also been determined for six of the cations in the same solvent.For derivatives of the same ring system, -ΔlogK is approximately equal to ΔpKR, but a 4 log unit discrepancy appears when phenanthridine derivatives are compared with the 9-methylacridinium ion.
Regioselectivity of Hydride Transfer to and between NAD+ Analogues
Roberts, R. M. G.,Ostovic, D.,Kreevoy, M. M.
, p. 2053 - 2056 (2007/10/02)
The reaction of 1-methyl- or 1-benzylquinolinium compounds, also bearing an electron-withdrawing substituent in the 3-position, with NaBH4, gives mixtures of the corresponding 1,2-dihydroquinolines and 1,4-dihydroquinolines in which the 1,2-dihydro derivatives usually predominate.The 1,2-derivatives can be isolated.The 1,2-isomers react with the quinolinium salts, giving the 1,4-isomers and regenerating quinolinium salts.This bimolecular isomerization can be used to convert a mixture of isomers to the 1,4-isomer on a preparative scale. 3-Cyano-1,2-dihydro-1-methylquinoline also isomerizes to the 1,2-isomer in the crystalline solid.The major first product of NaBH4 reduction of 3-(aminocarbonyl)-1-benzylpyridinium ion is the 1,6-dihydro derivative.This also isomerizes to the 1,4-dihydro compound in the presence of the pyridinium ion.Reduction of quinolinium derivatives with Na2S2O4 or a dihydropyridine directly produces the 1,4-isomer predominantly.Reduction of 3-(aminocarbonyl)-1-benzylpyridinium ion with Na2S2O4 in D2O gives the 1,4-dihydro derivative, but 8percent of the deuterium is in the 2-position; presumably by reversible isomerization.This deuterium redistribution may have important consequences for the interpretation of isotope effects.
