Efficient enantiomer selective acetylation of 1-methyl-3-phenylpropylamine by Fe₃O₄-APTES-CS₂-lipase magnetic nanoparticles in an alternating magnetic field

Abstract

Fe₃O₄ magnetic nanoparticles were prepared by chemical co-precipitation and modified with 3-aminopropyltriethoxysilane (APTES) and CS₂ to form Fe₃O₄-APTES-CS₂ magnetic carriers. Magnetically immobilized enzymes are attractive owing to their potential applications in many biological fields. When an alternating magnetic field is applied, the magnetic nanoparticles experience a force in the direction of the field, and the magnetic moments of the magnetic nanoparticles are apt to align in the direction of the field. Thus, magnetic nanoparticles behave like microscopic stirrers. The optimal reaction conditions of the acylation reaction using Fe₃O₄-APTES-CS₂-lipase were 200 mmol/L 1-methyl-3-amphetamine, 100 mg immobilized lipase, 200 μL ethyl acetate, 12.6 × g rotating speed, 40 °C, and 5 days in the shaker. The conversion and enantiomeric excess of R-2a reached a maximum of 36.8% and 98.5%, respectively. 1-Methyl-3-phenylpropylamine was resolved using Fe₃O₄-APTES-CS₂-lipase in an alternating magnetic field. The optimal magnetic field frequency and magnetic field intensity were determined to be 500 Hz and 12 Gs, respectively. The conversion and enantiomeric excess of R-2a reached a maximum of 40.3% and 98.5%, respectively. The results revealed that conversion under a magnetic field was significantly higher than that without a magnetic field. Highly optically active (R)-N-acetyl-1-methyl-3-amphetamine can be obtained via an efficient resolution of racemic 1-methyl-3-phenylpropylamine with immobilized lipase magnetic nanoparticles as a catalyst and ethyl acetate as an acyl donor in organic solvents in an alternating magnetic field.

Keywords:

• Alternating magnetic field
• Fe₃O₄-APTES-CS₂-lipase
• organic solvents
• resolution of racemic 1-methyl-3-phenylpropylamine
• (R)-N-acetyl-1-methyl-3-amphetamine

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The present work was financially supported by the National Nature Science Foundation of China [21978267] and the Natural Science Foundation of Zhejiang Province [LY15B060005, LY15B060007].