621-59-0Relevant articles and documents
One-Pot Biocatalytic In Vivo Methylation-Hydroamination of Bioderived Lignin Monomers to Generate a Key Precursor to L-DOPA
Birmingham, William R.,Galman, James L.,Parmeggiani, Fabio,Seibt, Lisa,Turner, Nicholas J.
, (2022/01/13)
Electron-rich phenolic substrates can be derived from the depolymerisation of lignin feedstocks. Direct biotransformations of the hydroxycinnamic acid monomers obtained can be exploited to produce high-value chemicals, such as α-amino acids, however the reaction is often hampered by the chemical autooxidation in alkaline or harsh reaction media. Regioselective O-methyltransferases (OMTs) are ubiquitous enzymes in natural secondary metabolic pathways utilising an expensive co-substrate S-adenosyl-l-methionine (SAM) as the methylating reagent altering the physicochemical properties of the hydroxycinnamic acids. In this study, we engineered an OMT to accept a variety of electron-rich phenolic substrates, modified a commercial E. coli strain BL21 (DE3) to regenerate SAM in vivo, and combined it with an engineered ammonia lyase to partake in a one-pot, two whole cell enzyme cascade to produce the l-DOPA precursor l-veratrylglycine from lignin-derived ferulic acid.
Method for synthesizing isovanillin
-
Paragraph 0019; 0031-0039; 0041-0051, (2021/07/31)
The invention provides a method for synthesizing isovanillin, and belongs to the technical field of chemical engineering. The method for synthesizing isovanillin comprises the steps of (1) conducting a methylation reaction, specifically, adding ethyl vanillin, dimethyl sulfoxide, Pd (OAc) 2 and a sodium hydroxide solution into a reaction kettle, carrying out oxygen replacement, controlling the oxygen pressure at 0.2 MPa, reacting at the temperature of 100 DEG C for 6 hours, ending the reaction, and filtering and separating the reaction liquid to obtain an oil-phase intermediate; (2) conducting a hydrolysis reaction, specifically, adding the oil-phase intermediate, a SO4/ZrOTiO2 catalyst and water into the reaction kettle, reacting at the temperature of 65 DEG C, and ending the reaction; carrying out suction filtration on the reaction liquid, dissolving a filter cake with 2000g of ethanol, carrying out heat preservation stirring at the temperature of 60 DEG C for 2-6 hours, and carrying out suction filtration; cooling the filtrate to 0 DEG C, preserving heat and stirring for 2-6 hours, and performing suction filtration to obtain a wet product; and drying the obtained solid in vacuum until the weight is constant to obtain the isovanillin.
Regioselectivity of Cobalamin-Dependent Methyltransferase Can Be Tuned by Reaction Conditions and Substrate
Pompei, Simona,Grimm, Christopher,Farnberger, Judith E.,Schober, Lukas,Kroutil, Wolfgang
, p. 5977 - 5983 (2020/10/06)
Regioselective reactions represent a significant challenge for organic chemistry. Here the regioselective methylation of a single hydroxy group of 4-substituted catechols was investigated employing the cobalamin-dependent methyltransferase from Desulfitobacterium hafniense. Catechols substituted in position four were methylated either in meta- or para-position to the substituent depending whether the substituent was polar or apolar. While the biocatalytic cobalamin dependent methylation was meta-selective with 4-substituted catechols bearing hydrophilic groups, it was para-selective for hydrophobic substituents. Furthermore, the presence of water miscible co-solvents had a clear improving influence, whereby THF turned out to enable the formation of a single regioisomer in selected cases. Finally, it was found that also the pH led to an enhancement of regioselectivity for the cases investigated.