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Optimization and kinetic modeling of lipase catalyzed enantioselective N ‐acetylation of ( ± )‐1‐phenylethylamine under microwave irradiation
Author(s) -
Sontakke Jyoti B.,
Yadav Ganapati D.
Publication year - 2011
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.2582
Subject(s) - kinetic resolution , lipase , chemistry , enantiomeric excess , enantioselective synthesis , catalysis , enantiomer , amine gas treating , organic chemistry , candida antarctica , biocatalysis , enzyme catalysis , nuclear chemistry , reaction mechanism , enzyme
BACKGROUND: Optically pure amines are used in the fine chemical industry as resolving agents, chiral auxiliaries, and chiral synthetic building blocks for pharmaceuticals as well as agrochemicals. Lipase‐catalyzed kinetic resolution of ( ± )‐1‐phenylethylamine with ethyl acetate as an acyl donor was achieved using immobilized lipase (Novozyme 435) as a biocatalyst under microwave irradiation. RESULTS: Response surface methodology was employed with a four‐factor‐three‐level Box‐Behnken design to evaluate the effect of synthesis parameters (speed of agitation, enzyme loading, temperature and acyl donor:amine molar ratio) on conversion, enantiomeric excess, enantioselectivity and initial rate. The optimum reaction conditions obtained were mole ratio of acyl donor:amine 1:1, temperature 49.86 °C, 0.03 g of catalyst loading and 345 rpm speed of agitation, giving 49.12% conversion, 78.83% enantiomeric excess and an enantioselectivity of 38.21. R‐stereopreference of lipase was analyzed in detail from the aspects of enzymatic kinetic mechanism and reaction activation energy of both enantiomers. CONCLUSION: Novozyme 435 was found to be the most active chiral catalyst for resolution of ( ± )‐1‐phenylethylamine under microwave irradiation. Statistical analysis was satisfactorily used to determine the optimum reaction conditions. It was found that lipase has R‐stereopreference and the reaction matches the Ping Pong Bi Bi mechanism with dead‐end inhibition of 1‐phenylethylamine. Copyright © 2011 Society of Chemical Industry