Selective biotransformation of substituted alicyclic nitriles by Rhodococcus equi A4

Abstract

Nitrile hydratase from Rhodococcus equi A4 discriminated between geometric isomers of substituted alicyclic nitriles. The enzyme transformed trans-4-benzoyloxycyclohexanecarbonitrile (trans-1a), cis-3-benzoyloxy cyclohexanecarbonitrile (cis-2a), trans-2-hydroxycyclohexanecarbonitrile (trans-3a), and trans-2-hydroxycyclo pentanecarbonitrile (trans-4a) into the corresponding amides. On the contrary, cis-2-hydroxycyclohexanecarbonitrile (cis-3a) and cis-2-hydroxycyclopentanecarbonitrile (cis-4a) were not converted to a significant extent. cis-4-Ben zoyl oxycyclohexanecarbonitrile (cis-1a) was also a substrate of the enzyme but reacted slowly. Diequatorial arrangement of the substituents in trans-1a, cis-2a, and trans-3a appears to positively influence the activity of the nitrile hydratase.