17033-11-3

Upstream product

• 108-48-5 2,6-dimethylpyridine 
• 952-92-1 1-benzyl-1,4-dihydronicotinamide radical cation 
• 3999-42-6 2.6-(CH₃)2C₅H₃N*BH₃ 
• 15454-31-6 iodate 

Downstream Products

• 108-48-5 2,6-dimethylpyridine 
• 62907-61-3 2,6-di-tert-butylpyridinium ion 

Relevant academic research and scientific papers

Non-steady-state kinetic studies of the real kinetic isotope effects and Arrhenius activation parameters for the proton transfer reactions of 9,10-dimethylanthracene radical cation with pyridine bases

The kinetics of the reactions between 9,10-dimethylanthracene radical cation and 2,6-diethylpyridine (DEP) in dichloromethane-Bu4NPF6 (0.2 M) as well as that with 2,6-dimethylpyridine (LUT) in acetonitrile-Bu4NPF6 (0.1 M) were studied at temperatures ranging from 252 to 312 K. In the time period before steady-state was reached for both reaction systems at all temperatures, the apparent deuterium kinetic isotope effects (KIEapp) were observed to increase with extent of reaction. The KIEapp-extent of reaction profiles provide strong evidence for a two-step mechanism [eqns. (i),(ii)] consisting of reversible complex formation prior to rate determining proton transfer. (i) ArCH3+. + B ? ArCH3+./B Keq = kf/kb (ii) ArCH3+./B → ArCH2. + BH+ kp (iii) ArCH2. + ArCH3+. + B → Products fast. Resolution of the kinetics into the relevant microscopic rate constants resulted in real deuterium kinetic isotope effects (KIEreal) which are much larger than KIEapp and were observed to increase markedly with decreasing temperature. Values of KIEreal ranged from 62 to 247. It is concluded that a significant degree of quantum mechanical tunneling is involved for both reaction systems. Activation parameters for apparent and microscopic rate constants are discussed with reference to the proton tunneling effect.

Application of non-steady-state kinetics to resolve the kinetics of proton-transfer reactions between methylarene radical cations and pyridine bases

Apparent deuterium kinetic isotope effects (KIE(app)) of four different methylarene radical cation-pyridine base reactions in dichloromethane (0.2 M tetrabutylammonium hexafluorophosphate) were observed to increase toward a constant value with increasing extent of reaction. The reactions were studied by derivative cyclic voltammetry (DCV), and rate constants were assigned by comparing the experimental with the theoretical DCV data. The kinetic results rule out a simple second-order proton-transfer reaction and implicate a mechanism in which a complex is first formed that then undergoes proton transfer, followed by separation of the products. That KIE(app) are extent of reaction-dependent is observed before steady-state is reached. The concurrent analysis of kinetic data for the reactions of both ArCH3(·+) and ArCD3(·+) with bases under non-steady-state conditions facilitates the resolution of the apparent rate constant [k(app) = k(f)k(p)/(k(b) + k(p))] into the microscopic rate constants (k(f), k(b), and k(p)) for the individual steps. The KIE(app) observed during proton-transfer reactions need not be the real kinetic isotope effects (KIE(real)). Having access to the microscopic rate constants for the steps in which the proton is transferred allows KIE(real) to be evaluated and compared with the corresponding KIE(app). The present study shows that the KIE(real) are much greater than the KIE(app) derived in the usual way from the rate of the overall reaction.

Steric and kinetic isotope effects in the deprotonation of cation radicals of NADH synthetic analogues

The deprotonation rate constants and kinetic isotope effects of the cation radicals have been determined by combined use of direct electrochemical techniques at micro- and ultramicroelectrodes, redox catalysis, and laser flash photolysis, over a extended

Amine boranes. III. Propanolysis of pyridine boranes

The solvolysis kinetics in 1-propanol of a number of alkyl-substituted pyridine boranes was studied. The reactions were first order in amine borane. Linear variation of log k with pKa of the pyridinium ion was observed for groups of compounds with the same ortho substituents; steric enhancement of rate was attributed to 1.1 and 3.5 kcal./mole of strain relief in the transition state for one or two o-methyl groups, respectively. It was concluded that the solvolysis mechanism involves B-N cleavage in the slow step. It was found that the free energy of the transition state referred to the dissociation products was invariant with substitutions on the pyridine ring.