title: Kinetic and thermodynamic analysis for lipase-catalyzed hydrolytic resolution of (R,S)-alcohols though their azolyl carbamates.
abstract: A new approach to the lipase-catalyzed hydrolytic resolution of (R,S)-azolyl carbamates for obtaining chiral azolyl carbamates and alcohol is described. With (R,S)-1-phenylethyl azolyl carbamates as the model substrates, the best reaction condition of using (R,S)-1-phenylethyl 4-bromopyrazole carbamate (1) as the substrate in water-saturated diisopropyl ether at 45 °C is selected. The kinetic constants, and hence enantiomeric ratio of 124, are then estimated from the kinetic analysis by considering the alcohol inhibition effect, with which theoretical time-course conversions for both enantiomers are numerically solved and agree with the experimental data. The thermodynamic parameters -ΔΔH and -ΔΔS satisfying a linear enthalpy-entropy compensation relationship of -ΔΔS = -38.84 + 3.29(-ΔΔH) are further estimated. An extension of the resolution platform to (R,S)-4-bromopyrazole carbamates derived from other (R,S)-alcohols (4, 5, 7) is also addressed.
authors.affiliation: Institute of Biochemical and Biomedical Engineering, Chang Gung University, Kwei-Shan, Tao-Yuan, 33302, Taiwan.
authors.forename: Ya-Ling
authors.initials: YL
authors.lastname: Cheng
authors.forename: An-Chi
authors.initials: AC
authors.lastname: Wu
authors.forename: Pei-Yun
authors.initials: PY
authors.lastname: Wang
authors.forename: Shau-Wei
authors.initials: SW
authors.lastname: Tsai
mesh_terms: D002219:Carbamates / Q000737:chemistry*; D004800:Enzymes, Immobilized; D005233:Fatty Alcohols / Q000737:chemistry*; D005656:Fungal Proteins; D007700:Kinetics; D008049:Lipase / Q000737:chemistry*; D008956:Models, Chemical; D013379:Substrate Specificity; D013816:Thermodynamics
chemical_list: D002219:Carbamates; D004800:Enzymes, Immobilized; D005233:Fatty Alcohols; D005656:Fungal Proteins; C093667:Novozyme 435; D008049:Lipase