Oxidation of Secondary Amines by Molecular Oxygen and Cyclohexanone Monooxygenase.

Abstract—Cyclohexanone monooxygenase from Acinetobacter calcoaceticus catalyzed the oxidation of tertiary and secondary amines toN-oxides and nitrones, respectively. The formation of a hydroxylamine intermediate was involved with secondary amines as startingsubstrates.q 2003 Elsevier Ltd. All rights reserved. 1. IntroductionThe increasing demand for enantiomerically pure com-pounds for the pharmaceutical and agrochemical industriesimplies a great incentive for the study of the biotransform-ations. Oxidative biotransformations are amongst the mostuseful of all identified biologically mediated conversions. 1 They usually involve monooxygenases or dioxygenases,that catalyze the insertion of one oxygen or two oxygenatoms at a specific point of a molecule, often with highstereo and/or regioselectivity. The cyclohexanone mono-oxygenase from Acinetobacter calcoaceticus NCIMB 9871(CHMO) (EC 1.14.13.22) is an interesting enzyme for itsapplication in the manufacture of fine chemicals and inorganic synthesis.