Efficient bio-catalytic production of enentiopure (S)-(4-chlorophenyl)(phenyl)methanol as a drug precursor by using a novel rotatable composite design-based optimization strategy

Asymmetric bioreductions catalyzed by biocatalysts have demonstrated great promise in manufacturing chiral alcohols. On the other hand, the synthesis of (S)-(4-chlorophenyl)(phenyl)methanol ((S)-2), precursors of L-cloprastine and carbinoxamine, still presents considerable challenges due to the inadequate substrate quantity and production process. In this work, a novel rotatable composite design-based optimization technique was used with the Lactobacillus paracasei BD101 biocatalyst for the asymmetric reduction of (4-chlorophenyl)(phenyl)methanone (1). Optimization conditions of the reaction were determined by the proposed optimization strategy as: pH=5.85, temperature=37 °C, incubation time=71 h, and agitation speed=120 rpm. The reaction conversion and the product of enantiomeric excess (ee) were also predicted to be 97% and 99%, respectively. In the experimental study performed under the determined optimized conditions, (S)-2 was obtained with >99% ee, >99% conversion, and 97% yield. In addition, 1 with the amount of 15.166 g was completely converted to (S)-2 (14.85 g, 97% isolated yield) on a high-gram scale. Notice that the manufacture of (S)-2 on a gram scale utilizing a biocatalyst and an optimization technique is demonstrated in this work for the first time. Finally, an economical, effective, and environmentally friendly biocatalytic process for the biocatalytic synthesis of (S)-2, which have antitussive and antiemetic properties and relax the bronchial muscle, has been demonstrated by the novel rotatable composite design-based optimization method.