Kinetics of the hydride reduction of an NAD(+) analogue by isopropyl alcohol in aqueous and acetonitrile solutions: solvent effects, deuterium isotope effects, and mechanism.

The rate constants of the hydride-transfer reactions from isopropyl alcohol (i-PrOH) to an NAD(+) model, 9-phenylxanthylium ion (PhXn(+)), in acetonitrile (AN) and in water containing AN (80% H(2)O/20% AN) were determined over a temperature range from 36 to 67 degrees C. The reactions follow second-order rate laws. In the latter solution, formation of the water adduct of PhXn(+) was observed as a side-equilibrium (K).