10.1016/j.tetasy.2008.01.036
The research focuses on the use of crude Mung bean (Phaseolus radiatus) epoxide hydrolase immobilized in a gelatin matrix for the stereoselective resolution of glycidate esters, specifically ethyl trans-(±)-3-phenyl glycidate (1a) and methyl trans-(±)-3-(4-methoxyphenyl) glycidate (1b). The experiments involved the immobilization of the enzyme in a gelatin gel, which was then used to selectively open the epoxide ring of the glycidate esters, yielding (2S,3R)-glycidate esters with high enantiomeric excess (ee >99%) and good yields (45% for 1a and near quantitative for 1b). The reactions were carried out in diisopropyl ether, and the products were analyzed using chiral HPLC to determine their enantiomeric purity and configuration. The study also explored the effects of gelatin concentration and water content on enzyme stability and activity, optimizing these conditions for the best enzyme performance. The research demonstrated a sustainable and efficient method for the preparation of enantiomerically pure glycidate esters, which are important drug intermediates.
10.1016/j.tet.2009.01.058
The study focuses on the nonenzymatic kinetic resolution of racemic 2,2,2-trifluoro-1-aryl ethanols, utilizing (R)-benzotetramisole as a catalyst. The aim was to achieve enantioselective acylation, which is crucial for obtaining chiral 1-substituted 2,2,2-trifluoro-ethanols, important intermediates in the synthesis of biologically active molecules. Various aryl-substituted ethanols were tested to evaluate the system's ability to differentiate between enantiomers, with a focus on the impact of different aryl groups on the enantioselectivity, as indicated by the s value. The study also optimized reaction conditions, including the choice of catalyst, acylating reagent, solvent, and reaction temperature, to maximize enantioselectivity and reaction efficiency. The chemicals used served specific purposes: (R)-benzotetramisole as the catalyst to facilitate the reaction, isobutyric anhydride as the acylating reagent to promote acylation, and diisopropyl ether as the solvent providing the appropriate polarity for the reaction. The study demonstrated that certain aryl groups, particularly phenyl and naphthyl groups, could yield high s values, indicating effective kinetic resolution. The research also provided preparative kinetic resolution examples to showcase the method's applicability in preparing enantiomerically pure 2,2,2-trifluoro-1-aryl ethanol derivatives.
10.1016/S0957-4166(01)00258-0
The research aimed to resolve 2-aryloxy-1-propanols, a class of primary alcohols with an oxygen atom at the stereocenter, with good to high enantioselectivity using Pseudomonas sp. lipase-catalyzed acylation with vinyl butanoate in di-iso-propyl ether. The study examined the impact of various factors on enantioselectivity, including solvents, acyl donors, and temperature. The researchers successfully prepared enantiomerically pure (R)-2-(4-chlorophenoxy)-1-propanol on a gram scale, demonstrating that Pseudomonas lipases are effective for the resolution of primary alcohols. Key chemicals used in the process included 2-aryloxy-1-propanols, vinyl butanoate, and various lipases from different sources, as well as solvents such as di-iso-propyl ether, acetonitrile, and benzene. The conclusions highlighted the significance of the acyl donor and temperature on the enantioselectivity of the enzymatic transesterification, showcasing the utility of Pseudomonas sp. lipases in achieving high enantiomeric purity of primary alcohols.
10.1021/ja952674t
The research aims to develop a quantitative model that predicts the solvent dependence of enzymatic selectivity based on the thermodynamics of substrate solvation. The study concludes that enzymatic prochiral selectivity in anhydrous organic solvents can be primarily attributed to changes in the relative solvation energies for the pro-R and pro-S binding modes of the substrate in the transition state. The model was found to perform well with crystalline enzymes, but not with amorphous enzyme powders due to their ill-defined structure. Key chemicals used in the process include γ-chymotrypsin, subtilisin Carlsberg, vinyl acetate, 2-(3,5-dimethoxybenzyl)-1,3-propanediol, and various organic solvents such as diisopropyl ether, cyclohexane, and acetonitrile, among others.
10.1016/j.tet.2004.12.059
The research focuses on the preparation of optically active b-hydroxy-b-arylpropionates, d-hydroxy-d-aryl-b-oxo-pentanoates, and their butyryl derivatives via CRL-catalyzed hydrolysis. These chiral compounds are important precursors for various chiral pharmaceuticals and natural products. The study explores the use of Candida Rugosa lipase (CRL) to achieve enantioselective hydrolysis and alcoholysis of these compounds, resulting in high yields and good enantioselectivity. Key chemicals involved in the research include the substrates b-hydroxy-b-arylpropionates and d-hydroxy-d-aryl-b-oxo-pentanoates, as well as reagents such as DCC/butyric acid for butyrylation and MgCl2 for pre-equilibration in the hydrolysis process. The research also involves the use of various solvents like diisopropyl ether and CH2Cl2, and analytical techniques such as IR, NMR, and HPLC to characterize the products and assess their enantioselectivity.
F
F:Flammable;
