* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
With C39H33N3O2*2ClH In methanol; water at 20℃; for 72 h;
General procedure: To a 5 mL vial equipped with a magnetic stirrer bar were added 3-cyclohexyl-2-oxopropanoic acid (1j) (0.0510 g, 0.30 mmol), 2,2-diphenylglycine (2) (0.0681 g, 0.30 mmol), chiral pyridoxamine 6g (0.0195 g, 0.030 mmol), and MeOH-H2O (8:2) (3.0 mL). The mixture was stirred at 20 °C for 3 days. The reaction mixture was transferred to a 25 mL round-bottom flask and MeOH was added until all the solid was dissolved. Then silica gel (0.50 g) was added. After removal of the solvent in vacuo at 20 °C, the resulting residue was submitted to column chromatography on silica gel (EtOH/ethyl acetate/25-28percent ammonia solution =100:58:16) to give compound 3j (0.0401 g, 78percent yield, 52percent ee) as a white solid. The enantiomeric excesses of 3b-k were deteremined by HPLC analysis after being converted to N-benzoyl methyl esters by treatment with thionyl chloride in methanol and subsequent reaction benzoyl chloride.7 The enantiomeric excess of 3a was deteremined by HPLC analysis after being converted to its methyl ester by treatment with CH2N2 in methanol.
Screening of nitrilases against target substrate 4-methyl-D-leucine and 4-methyl-L-leucine (0269) Hydrolysis of 2-amino-4,4-dimethyl pentanenitrile was performed by several of the nitrilases. Of these, some were shown to hydrolyse the nitrile to the L-isomer of the corresponding acid and were selected for further characterization. [tabl0013-en] Table 10. Summary of hit enzymes for enantioselective hydrolysis of 2-amino-4,4-dimethyl pentanenitrileSEQ ID NOS: Conversion To Product (percent) Time For Highest Conversion (h) ee (percent) Turnover (g Product/kg Nitrilase/h) Specific Activity (μmol Product/mg Nitrilase/h) Conditions1 103, 104 30 0.5 91 12489 36 pH 7, room temp 59, 60 30 0.5 >99 33806 233 pH 7, room temp 221, 222 32 7.5 79 1098 7 pH 6, 38 °C [tabl0014-en] Table 11. Summary of optimal conditions determined from characterization experiments for enantioselective hydrolysis of 2-amino-4,4-dimethyl pentanenitrileSEQ ID NOS: Optimum pH Optimum Temp °C Solvent Tolerance 103, 104 7 23 25percent MeOH, 10percent IPA 59,60 8 23 25percent MeOH 221,222 6 38 25percent MeOH, 10percent IPA
With C39H33N3O2*2ClH In methanol; water at 20℃; for 72 h;
General procedure: To a 5 mL vial equipped with a magnetic stirrer bar were added 3-cyclohexyl-2-oxopropanoic acid (1j) (0.0510 g, 0.30 mmol), 2,2-diphenylglycine (2) (0.0681 g, 0.30 mmol), chiral pyridoxamine 6g (0.0195 g, 0.030 mmol), and MeOH-H2O (8:2) (3.0 mL). The mixture was stirred at 20 °C for 3 days. The reaction mixture was transferred to a 25 mL round-bottom flask and MeOH was added until all the solid was dissolved. Then silica gel (0.50 g) was added. After removal of the solvent in vacuo at 20 °C, the resulting residue was submitted to column chromatography on silica gel (EtOH/ethyl acetate/25-28percent ammonia solution =100:58:16) to give compound 3j (0.0401 g, 78percent yield, 52percent ee) as a white solid. The enantiomeric excesses of 3b-k were deteremined by HPLC analysis after being converted to N-benzoyl methyl esters by treatment with thionyl chloride in methanol and subsequent reaction benzoyl chloride.7 The enantiomeric excess of 3a was deteremined by HPLC analysis after being converted to its methyl ester by treatment with CH2N2 in methanol.
Reference：
[1] Journal of the Chemical Society, Chemical Communications, 1994, # 17, p. 1915 - 1916
8
[ 479353-90-7 ]
[ 57224-50-7 ]
[ 88319-43-1 ]
Yield
Reaction Conditions
Operation in experiment
79% ee
at 20℃; for 7.5 h; Enzymatic reaction
Screening of nitrilases against target substrate 4-methyl-D-leucine and 4-methyl-L-leucine (0269) Hydrolysis of 2-amino-4,4-dimethyl pentanenitrile was performed by several of the nitrilases. Of these, some were shown to hydrolyse the nitrile to the L-isomer of the corresponding acid and were selected for further characterization. [tabl0013-en] Table 10. Summary of hit enzymes for enantioselective hydrolysis of 2-amino-4,4-dimethyl pentanenitrileSEQ ID NOS: Conversion To Product (percent) Time For Highest Conversion (h) ee (percent) Turnover (g Product/kg Nitrilase/h) Specific Activity (μmol Product/mg Nitrilase/h) Conditions1 103, 104 30 0.5 91 12489 36 pH 7, room temp 59, 60 30 0.5 >99 33806 233 pH 7, room temp 221, 222 32 7.5 79 1098 7 pH 6, 38 °C [tabl0014-en] Table 11. Summary of optimal conditions determined from characterization experiments for enantioselective hydrolysis of 2-amino-4,4-dimethyl pentanenitrileSEQ ID NOS: Optimum pH Optimum Temp °C Solvent Tolerance 103, 104 7 23 25percent MeOH, 10percent IPA 59,60 8 23 25percent MeOH 221,222 6 38 25percent MeOH, 10percent IPA
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