Clenbuterol, is a β2-adrenergic agonist (β2-adrenergic agonist), similar to ephedrine (Ephedrine), is often used clinically to treat chronic obstructive pulmonary disease (COPD), It is also used as a bronchodilator to relieve acute exacerbations of asthma. In the early 1980s, the American company Cyanamid accidentally discovered that it has obvious effects of promoting growth, improving lean meat rate and reducing fat, so it was used as clenbuterol in animal husbandry. However, due to its side effects, the European Community banned the use of clenbuterol as a feed additive since January 1, 1988. It was banned by the FDA in 1991. In 1997, the Ministry of Agriculture of the People's Republic of China strictly prohibited the use of beta-adrenergic hormones in feed and animal husbandry production, and Clenbuterol hydrochloride ranked first.

However, racemic Clenbuterol has recently been shown to reduce the risk of Parkinson's disease. To confirm which (or both) isomers produce this effect, the pure Clenbuterol enantiomer needs to be studied separately.

In a recent article, the research group of Elisabeth Egholm Jacobsen of the Department of Chemistry, Norwegian University of Science and Technology, in collaboration with Dr. Zhu Wei of Syncozymes, catalyzed the synthesis of ketoreductase KRED and cofactor nicotinamide adenine dinucleoside phosphate (NADPH). (R)-1-(4-Amino-3,5-dichlorophenyl)-2-bromoethan-1-ol, ee > 93%; and (S)-N-(2 was synthesized by the same system ,6-Dichloro-4-(1-hydroxyethyl)phenyl)acetamide, ee >98%. Both of the above intermediates are potential precursors of clenbuterol isomers. The ketoreductase ES-KRED-228 used in this study was from Syncozymespharmaceutical (Shanghai) Co., Ltd. The research result "Chemoenzymatic Synthesis of Synthons as Precursors for Enantiopure Clenbuterol and Other -2-Agonists" was published in "Catalysts" on November 4, 2018.