A study on the development of molecularly imprinted polymer (MIP)-based protecting group for the synthesis of l-a-aspartame

• Main Author: Francia, Chris Allen Earl T.
• Format: text
• Language: English
• Published: Animo Repository 2017
• Subjects: Imprinted polymers; Molecular imprinting; Molecular recognition
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/5697
• Institution: De La Salle University

The study explored the development of molecularly imprinted polymer (MIP) as protecting group for formation of amide bond between aspartic acid and phenylalanine. The MIP was synthesized using standard l-a-aspartame as template and 2-methoxy-4- vinylphenol as functional monomer with divinylbenzene as host monomer. The MIP was prepared by thermo chemically initiated bulk polymerization. The protocol used for deciding the ratio of functional monomer and template in MIP was based on partial Computational Molecular Modelling using Spartan semi-empirical method. Some experimental test trials were conducted to roughly find the working volume of DVB crosslinker and Porogen with basis on previously reported MIP studies by Sellergren 2003 and Alexander, et al (1999). The 1:6 ratio of monomers and template based from modelling studies was used to synthesize the MIP. The MIP made, after template removal, was employed to aid the dipeptide synthesis from the amino acid precursors with thionyl chloride and methanol. FTIR characterization of MIP and its complexes revealed presence of spectral peaks differentiating each complexes and identifying aspartame complex from other MIP complexes. TGA data suggest low substrate to MIP ratio implying low product yield. SEM gave visualization of the MIP's overall porous and rough solid surface. This was supplemented by N2 adsorption/desorption analyses for porosity by BJH method and surface area measurement by BET that gave an ave. pore radius of 19.298Å, categorizing the MIP developed as microporous, and an ave. surface area of 404.596 m2/g. The formation of dipeptide product was indicated by presence of m/z 295.1196 in MS, amide bond of product complex in FTIR, and amide proton peak in Nuclear Magnetic Resonance (NMR). Together, the NMR and Mass spectral data shows formation of methoxylated dipeptide of aspartic acid and phenylalanine.