Studies of enzyme-mediated reactions. Part IV. Complementary syntheses of stereospecifically labelled (R)- and (S)-[α-3H1]benzyl alcohol derivatives by use of liver alcohol dehydrogenase

Abstract

Thermodynamic and kinetic parameters for the reduction of benzaldehydes with liver alcohol dehydrogenase and NADH have been studied. This has led to an efficient synthesis of (R)-[α-3H1]benzyl alcohols from potassium borotritiide as labelled starting material which involves tritiated cyclohexanol as the reducing agent in the enzymic step. Since the S-isomers can also be prepared readily, studies of enzymic reactions at prochiral centres ArCH2X can be strengthened by having both R- and S-labelled substrates available. Methods have been devised for the preparative enzymic oxidation of benzyl alcohols to benzaldehydes, and this procedure is used to study the configurational purities of a range of [α-3H1]benzyl alcohols.