As a renewable source, fructose is of great significance in biomass conversion and in the food industry. Currently, there are many limitations to the enzymatic method of fructose preparation used in industry. In this study, the combination of CaCl2 and Et3N is introduced for the glucose–fructose isomerization in methanol, and the reagents are not promoting this reaction independently. Various factors that influence the reaction were tested and up to 77.8% fructose yield was obtained with Et3N and CaCl2 as reagents in methanol at 65 °C. It is observed that the ternary complex formed by Et3N, CaCl2 and monosaccharide, could promote the reaction in the direction of the formation of fructose, by shifting the equilibrium of the glucose to fructose isomerization. After the reaction, the fructose-complex precipitates as this complex has lower solubility in methanol. The fructose-complex was separated from reaction mixture and processed further to obtain high-purity fructose in 44.8% isolated yield. Moreover, the filtrate containing solvent and reagents obtained in the separation process can easily be recycled. The process of the isomerization reaction was found to involve intramolecular hydride shift and enediol intermediate mechanism at the same time, and the former is the major pathway.
A novel fully biocatalytic system for regio- and enantioselective hydroamination of 4-hydroxystyrenes to useful and valuable chiral amines in good yields and excellent ee.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Controllable synthesis of 3-thiolated pyrroles or pyrrolines was achieved by tuning the reaction solvents, allowing the efficient construction of bisthiolated BODIPY.
Switchable ortho/ipso-cyclization of N-arylpropynamides induced with N-sulfanylsuccinimides as general sulfur reagents is reported. In the presence of MeOH, para-fluoro N-arylpropynamides exclusively undergo the ipso-cyclization to give 3-sulfenyl azaspiro[4,5]trienones. Two kinds of bioactive heterocycles, benzothieno-[3,2-b]quinoline and -[2,3-c]quinolone, have been directly and efficiently prepared from the corresponding sulfenylated products.
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