Configurational differences in monosaccharides determine the products and selectivity of the transesterification reaction with lipase-B (CAL-B). The β-anomers of peresterified pyranose monosaccharides tend to yield anomeric deprotection products, while the α-anomers preferentially react at the sixth or fourth position. CAL-B differentiates between enantiomers, either reacting more rapidly with d-enantiomers of monosaccharides or having a different selectivity based on the enantiomer. Pivaloylated and benzoylated saccharides are the limits of the CAL-B transesterification reaction, while lower boiling point alcohols such as MeOH and EtOH can replace -BuOH as the nucleophilic reagent. Finally, CAL-B can be successfully recycled in both long and short reaction time reactions.
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http://dx.doi.org/10.1021/acs.joc.4c02582 | DOI Listing |
J Org Chem
January 2025
Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia.
Configurational differences in monosaccharides determine the products and selectivity of the transesterification reaction with lipase-B (CAL-B). The β-anomers of peresterified pyranose monosaccharides tend to yield anomeric deprotection products, while the α-anomers preferentially react at the sixth or fourth position. CAL-B differentiates between enantiomers, either reacting more rapidly with d-enantiomers of monosaccharides or having a different selectivity based on the enantiomer.
View Article and Find Full Text PDFRSC Adv
January 2025
Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology Gokiso-cho, Showa-ku Nagoya Aichi Japan 466-8555
We recently proposed a concept of self-transformation from thermoplastic polyesters into vitrimers intermolecular bond exchange as the cross-linking reaction. Key was the use of polyesters bearing hydroxyl side groups, which were cross-linked without additional cross-linkers through intermolecular transesterification in the presence of a suitable catalyst. In our previous study, a linear polyester was synthesized as the starting polymer by reacting dithiol monomers containing ester bonds (2-SH) with diepoxy monomers (2-epoxy) a thiol-epoxy reaction, generating hydroxyl side groups along the polyester chain.
View Article and Find Full Text PDFHeliyon
December 2024
The Petroleum and Petrochemical College, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand.
Glycerol, a by-product of biodiesel production through transesterification, presents an opportunity for biodiesel industries to transform surplus glycerol into high-value chemical products. This study focuses on the development of a series of propyl sulfonic acid functionalized (PrSOH) SBA-15 catalysts, synthesized by direct synthesis of 3-mercaptopropyltrimethoxysilane (MPTMS) and tetraethoxysilane (TEOS) in an acidic medium. The catalysts were evaluated for acetylation of glycerol with acetic acid under conditions optimized through response surface methodology.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Johor Bharu, Malaysia.
As the demand for sustainable energy sources intensifies, biodiesel emerges as a compelling renewable alternative to petroleum-based fuels. Leveraging waste cooking oil (WCO) as a feedstock not only offers an environmentally friendly fuel source but also addresses waste disposal issues. However, biodiesel production from WCO faces challenges, particularly due to its high free fatty acid (FFA) content, which can hinder efficient conversion and lead to soap formation in traditional alkaline-catalysed processes.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, U.K.
The catalytic competency of the ribosome in extant protein biosynthesis is thought to arise primarily from two sources: an ability to precisely juxtapose the termini of two key substrates─3'-aminoacyl and -acyl-aminoacyl tRNAs─and an ability to ease direct transpeptidation by their desolvation and encapsulation. In the absence of ribosomal, or enzymatic, protection, however, these activated alkyl esters undergo efficient hydrolysis, while significant entropic barriers serve to hamper their intermolecular cross-aminolysis in bulk water. Given that the spontaneous emergence of a catalyst of comparable size and sophistication to the ribosome in a prebiotic RNA world would appear implausible, it is thus natural to ask how appreciable peptide formation could have occurred with such substrates in bulk water without the aid of advanced ribozymatic catalysis.
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