Figure 4.

Enzymatic selective alkylation of pyrazoles using haloalkanes. v36 and NSA‐synthase (50 μM each) was used as catalyst. The reactions were performed with 2 mM pyrazole (3) as substrate, 10 equiv. of haloalkane and 30 °C (iodo‐, bromoethane and iodopropane) as well as 37 °C (iodomethane). The reaction time was 30 h using iodomethane, 40 h in the iodomethane preparative scale reaction, 72 h in using haloethanes and 50 h with 1‐iodopropane. *This reaction was performed on preparative scale (1.0 mmol), please see SI for details. Regioselectivity is described as regioisomeric ratio (r.r.).