ie200574a_si_001.pdf (160.15 kB)
Kinetic and Thermodynamic Investigation of Lipase-Catalyzed Hydrolysis of (R,S)-3-Phenylbutyl Azolides
journal contribution
posted on 2012-03-07, 00:00 authored by Jin-Ru Chen, Chia-Hui Wu, Pei-Yun Wang, Shau-Wei TsaiWater-saturated cyclohexane at 25 °C is selected
as the best reaction condition for Novozym 435-catalyzed hydrolytic
resolution of (R,S)-3-phenylbutyl
4-methylpyazolide (1). The kinetic constants and enantiomeric
ratio of 36 are then estimated from the kinetic analysis and successfully
employed for simulating the time-course conversions of both enantiomers.
A feed-batch operation with water added during the reaction is proposed
for converting the fast-reacting enantiomer of high concentrations
to the product. A linear enthalpy–entropy compensation relationship
of −ΔΔS = −38.84 + 3.29(−ΔΔH) with R2 = 0.98 for the lipase-catalyzed
hydrolysis or alcoholysis of several (R,S)-azolides in anhydrous or water-saturated solvents is addressed.
The resolution platform is further extended to (R,S)-3-(Boc-amino)-3-phenylpropionyl 4-methylpyrazolide
(10), leading to improved enzyme activity and enantioselectivity
if anhydrous methyl tert-butyl ether or isopropanyl
ether is selected as the reaction medium.