25522-33-2Relevant articles and documents
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.
Specific Residues Expand the Substrate Scope and Enhance the Regioselectivity of a Plant O-Methyltransferase
Tang, Qingyun,Bornscheuer, Uwe T.,Pavlidis, Ioannis V.
, p. 3227 - 3233 (2019/07/04)
An isoeugenol 4-O-methyltransferase (IeOMT), isolated from the plant Clarkia breweri, can be engineered to a caffeic acid 3-O-methyltransferase (CaOMT) by replacing three consecutive residues. Here we further investigated functions of these residues by constructing the triple mutant T133M/A134N/T135Q as well as single mutants of each residue. Phenolics with different chain lengths and different functional groups were investigated. The variant T133M improves the enzymatic activities against all tested substrates by providing beneficial interactions to residues which directly interact with the substrate. Mutant A134N significantly enhanced the regioselectivity. It is meta-selective or even specific against most of the tested substrates but para-specific towards 3,4-dihydroxybenzoic acid. The triple mutant T133M/A134N/T135Q benefits from these two mutations, which not only expand the substrate scope but also enhance the regioselectivity of IeOMT. On the basis of our work, regiospecific methylated phenolics can be produced in high purity by different IeOMT variants.
Synthesis and biological evaluation of novel neoflavonoid derivatives as potential antidiabetic agents
Wang, Bing,Li, Na,Liu, Teng,Sun, Jie,Wang, Xiaojing
, p. 34448 - 34460 (2017/07/22)
Various substituted neoflavonoid derivatives were synthesized using sulfated montmorillonite K-10 as a catalyst. This method is environmental friendly, sustainable and economical, convenient in isolation and purification processes, with little byproducts, using earth-abundant catalysts and has relatively high yield. Those neoflavonoid derivatives were screened for antioxidant, a-glucosidase inhibitory, aldose reductase 2 (ALR2) inhibitory and advanced glycation end-product formation inhibitory effects. Most compounds exhibited significant antioxidant and advanced glycation end-product (AGE) formation inhibitory activities. It was interesting to note that out of thirty compounds, 8k and 8l were found to have greater ALR2 inhibitory activity than the standard drug quercetin. The pharmacological studies suggested neoflavonoid with adjacent 7,8-dihydroxy groups were more effective in inhibiting ALR2. Antidiabetic activity studies had shown that compounds 8l and 8m were equipotent to the standard drug glibenclamide in vivo. In summary, the target compound 8l provided a potential drug design concept for the development of therapeutic or prophylactic agents of diabetes and diabetes complications.
