*Article Gordonia hydrophobica* **Nitrile Hydratase for Amide Preparation from Nitriles**

**Birgit Grill <sup>1</sup> , Melissa Horvat <sup>2</sup> , Helmut Schwab 1,2, Ralf Gross <sup>3</sup> , Kai Donsbach 3,4 and Margit Winkler 1,2,\***


**Abstract:** The active pharmaceutical ingredient levetiracetam has anticonvulsant properties and is used to treat epilepsies. Herein, we describe the enantioselective preparation of the levetiracetam precursor 2-(pyrrolidine-1-yl)butanamide by enzymatic dynamic kinetic resolution with a nitrile hydratase enzyme. A rare representative of the family of iron-dependent nitrile hydratases from *Gordonia hydrophobica* (*Gh*NHase) was evaluated for its potential to form 2-(pyrrolidine-1-yl)butanamide in enantioenriched form from the three small, simple molecules, namely, propanal, pyrrolidine and cyanide. The yield and the enantiomeric excess (*ee*) of the product are determined most significantly by the substrate concentrations, the reaction pH and the biocatalyst amount. *Gh*NHase is also active for the hydration of other nitriles, in particular for the formation of *N*-heterocyclic amides such as nicotinamide, and may therefore be a tool for the preparation of various APIs.

**Keywords:** small molecule; dynamic kinetic resolution; levetiracetam; nitrile hydratase; amino amide; amino nitrile
