TY - JOUR
T1 - Lipase-catalyzed enantioselective resolution of (R,S)-N-2-methylalkanoyl-3- (2-pyridyl)pyrazoles in organic solvents
AU - Lin, Yi Sheng
AU - Wang, Pei Yun
AU - Wu, An Chi
AU - Tsai, Shau Wei
PY - 2011/3
Y1 - 2011/3
N2 - The lipase-catalyzed resolution of (R,S)-pyrazolides containing a 2-aryl substituent to the α-chiral center has been successfully extended to (R,S)-N-2-methylalkanoyl-3-(2-pyridyl)pyrazoles (1-4) containing different alkanoyl-chain lengths. The best reaction condition for CALB-catalyzed hydrolysis of (R,S)-N-2-methylheptanoyl-3-(2-pyridyl)pyrazole (1) in water-saturated MTBE at 35 °C is selected, leading to an excellent enantioselectivity (VR/VS > 100) with improved initial specific activities in comparison with that of (R,S)-N-2-phenylpropionyl-3-(2- pyridyl)pyrazole. The thermodynamic analysis for the hydrolysis of 1 demonstrates great influences of water content and solvent hydrophobicity on varying the ehthalpic and entropic contributions in water-saturated and anhydrous MTBE and IPE, and leads to an excellent enthalpy-entropy compensation relationship ΔΔS = 3.113ΔΔH + 33.86 (r2 = 0.999). Moreover, a thorough kinetic analysis for all substrates indicates that a critical valeroyl-chain length for obtaining the enantiomer discrimination and improved lipase activity for the fast-reacting (R)-pyrazolide is needed.
AB - The lipase-catalyzed resolution of (R,S)-pyrazolides containing a 2-aryl substituent to the α-chiral center has been successfully extended to (R,S)-N-2-methylalkanoyl-3-(2-pyridyl)pyrazoles (1-4) containing different alkanoyl-chain lengths. The best reaction condition for CALB-catalyzed hydrolysis of (R,S)-N-2-methylheptanoyl-3-(2-pyridyl)pyrazole (1) in water-saturated MTBE at 35 °C is selected, leading to an excellent enantioselectivity (VR/VS > 100) with improved initial specific activities in comparison with that of (R,S)-N-2-phenylpropionyl-3-(2- pyridyl)pyrazole. The thermodynamic analysis for the hydrolysis of 1 demonstrates great influences of water content and solvent hydrophobicity on varying the ehthalpic and entropic contributions in water-saturated and anhydrous MTBE and IPE, and leads to an excellent enthalpy-entropy compensation relationship ΔΔS = 3.113ΔΔH + 33.86 (r2 = 0.999). Moreover, a thorough kinetic analysis for all substrates indicates that a critical valeroyl-chain length for obtaining the enantiomer discrimination and improved lipase activity for the fast-reacting (R)-pyrazolide is needed.
KW - (R,S)-N-2-methylalkanoyl-3-(2-pyridyl)pyrazoles
KW - Alcoholysis
KW - Hydrolysis
KW - Kinetic and thermodynamic analysis
KW - Lipases
UR - http://www.scopus.com/inward/record.url?scp=78651380641&partnerID=8YFLogxK
U2 - 10.1016/j.molcatb.2010.11.012
DO - 10.1016/j.molcatb.2010.11.012
M3 - 文章
AN - SCOPUS:78651380641
SN - 1381-1177
VL - 68
SP - 245
EP - 249
JO - Journal of Molecular Catalysis B: Enzymatic
JF - Journal of Molecular Catalysis B: Enzymatic
IS - 3-4
ER -