CHEMOENZYMATIC SYNTHESIS OF C-14-LABELED ANTIOXIDANTS

The syntheses of [C-14] labelled antioxidants are described. We developed an efficient synthetic methodology to prepare a series of labelled amides with antioxidant activity, starting from [C-14] KCN and alkyl or aryl halides. By a combination of nucleophilic displacement of halides by [C-14] cyanide, mediated by ultrasound and subsequent mild and selective enzymatic hydrolysis of the resulting nitriles, labelled carboxylic acids were obtained. Labelled amines were prepared by reduction of the respective nitriles. Availability of [C-14] KCN, efficient introduction of the label by ultrasound mediated reaction and selective and mild hydrolysis by commercially available nitrilase (Rhodococcus sp.), makes possible a wide range of applications of this methodology in the synthesis of functionalized labelled compounds.