Biocatalytic enantioselective preparation of phenothiazine-based cyanohydrin acetates: kinetic and dynamic kinetic resolution

Lipases: Valuable catalysts for dynamic kinetic resolutions

“…Reversible base-catalyzed formation of cyanohydrins in situ from prochiral aldehydes and cyanide group donors, such as 2-hydroxy-2-methylpropanenitrile, has been performed concurrently with enantioselective lipase-catalyzed acylation resulting in DKR of aliphatic and aromatic (Paizs et al, 2003(Paizs et al, , 2004Sakai et al, 2008;Sundell et al, 2013;Veum and Hanefeld, 2004; cyanohydrins. This method was successfully applied in the preparation of chiral phenonothiazinic cyanohydrins, which are useful intermediates in the synthesis of bioactive substances (Fig.…”

“…This method was successfully applied in the preparation of chiral phenonothiazinic cyanohydrins, which are useful intermediates in the synthesis of bioactive substances (Fig. 38) (Paizs et al, 2004).…”

Lipase-catalyzed kinetic resolution of racemic 1-(10-alkyl-10H-phenothiazin-3-yl)ethanols and their butanoates

“…The rotating group refinement procedure by maximization of the electron density was used for the hydroxyl groups. The final cycle (349 variable parameters) gave R 1 = 0.0423, wR 2 = 0.0674 (I > 2r(I)), and R 1 = 0.0775, wR 2 = 0.0830 (all data), S = 0.903, and the Flack parameter of À0.07 (6). 16 Drawings of the structure were done using the PLATON program.…”

Chemoenzymatic and microbial dynamic kinetic resolutions

“…They also observed that enzyme CAL-A was able to work with sterically hindered substrates under conditions where common lipases such as lipase PS and CAL-B failed. Kanerva and coworkers 75 reported the preparation of phenothiazine-based cyanohydrin acetates on the basis of similar methodology to that used in Scheme 26. Novel (1)-10-alkyl-phenothiazin-3ylhydroxy-acetonitriles (76) was prepared by enantioselective acylation with high enantioselectivity (Scheme 27).…”