77316-40-6Relevant academic research and scientific papers
Synthesis of Flavonols via Pyrrolidine Catalysis: Origins of the Selectivity for Flavonol versus Aurone
Xiong, Wei,Wang, Xiaohong,Shen, Xianyan,Hu, Cuifang,Wang, Xin,Wang, Fei,Zhang, Guolin,Wang, Chun
supporting information, p. 13160 - 13176 (2020/11/23)
A novel synthetic method for flavonol from 2′-hydroxyl acetophenone and benzaldehyde promoted by pyrrolidine under an aerobic condition in water is established. This protocol was supported by efficient synthesis of 44 common examples and three natural products. The α, β-unsaturated iminium ion (enimine ion E) was proved to be the key intermediate in the reaction. H218O and 18O2 isotope tracking experiments demonstrated that both water and the aerobic atmosphere were necessary to ensure the transformation. The selectivity for flavonol or aurone was originated from solvent-triggered intermediates, which were determined by UV-visible spectra from isolated enimine. The phenol-iminium E-A is dominant in water and the ketoenamine intermediate E-B is prevalent in acetonitrile. In the presence of pyrrolidine and oxygen, E-A leads to flavonol through E-I, a zwitterionic-like phenoloxyl-iminium ion, following the key steps of cyclization and a [2 + 2] oxidation; E-B proceeds through path II, a radical process induced by photolysis of E-B with both pyrrolidine and oxygen, to afford aurone. Preliminary mechanistic studies are reported.
Antibacterial Activity of a New Flavone Glycoside from the Stems of Holmskioldia sanguinea Retz.
Yadava,Raghuvansi, Jyotsna
, p. 1815 - 1818 (2019/07/18)
A new flavone glycoside was isolated from ethanolic extract of stem parts of Holmskioldia sanguinea Retz. Its structure was characterized as 3,4′-dihydroxy-5,7-dimethoxyflavone-3-O-β-D-galactopyranosyl(1→4)-O-β-D-arabinopyranosyl-4′-O-α-L-rhamnopyranoside (1) by colour reactions, chemical degradation and spectroscopic analysis. Antibacterial activity of compound 1 was evaluated against various Gram positive and Gram negative bacteria showing a significant effects.
A 3 - hydroxy flavone and its derivatives of aqueous phase one-pot synthesis method (by machine translation)
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Paragraph 0060-0063; 0072-0076, (2019/02/25)
The invention belongs to the field of chemical synthesis, in particular to a 3 - hydroxy flavone and its derivatives of the one-pot synthesis method of the aqueous phase. The invention relates to 2 - hydroxy acetophenone and its derivatives with the benzaldehyde and its derivatives as the substrate of reaction, or 2 - hydroxy chalcone and its derivatives as the substrate of reaction, water or ethanol aqueous solution as the solvent, under the aerobic condition, 20 - 100 °C, reaction to obtain 3 - hydroxy flavone and its derivatives. The present invention provides a new reaction mechanism, has developed an efficient, convenient, wide adaptability of the substrate 3 - hydroxy flavone synthesis method; the invention also the use of the new method to synthesize a brand-new 3 - hydroxy flavone derivatives, in the health care field has important application value. (by machine translation)
Microwave assisted dealkylation of alkyl aryl ethers in ionic liquids
Chauhan, Shive M. S.,Jain, Nidhi
, p. 693 - 694 (2007/10/03)
Alkyl aryl ethers undergo selective dealkylation in 1-butyl pyridinium bromide and 1-butyl-3-methyl imidazolium bromide ionic liquids under microwave irradiation to give the corresponding phenols in high yields. The ionic liquids serve the dual purpose of solvent as well as reagent and allow easy isolation of products.
