Synthesis of Flavonols via Pyrrolidine Catalysis: Origins of the Selectivity for Flavonol versus Aurone
作者:Wei Xiong、Xiaohong Wang、Xianyan Shen、Cuifang Hu、Xin Wang、Fei Wang、Guolin Zhang、Chun Wang
DOI:10.1021/acs.joc.0c01869
日期:2020.10.16
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
建立了一种在水中好氧条件下由吡咯烷促进的2'-羟基苯乙酮和苯甲醛合成黄酮醇的新方法。该协议得到44个常见实例和三种天然产物的有效合成的支持。事实证明,α,β-不饱和亚胺离子(亚胺离子E)是反应的关键中间体。H 2 18 O和18 O 2同位素跟踪实验表明,水和好氧气氛对于确保转化都必不可少。黄酮醇或金酮的选择性源自溶剂触发的中间体,该中间体由分离的亚胺的紫外可见光谱确定。酚亚胺EA在水中占主导地位,酮烯胺中间体EB在乙腈中盛行。在环化和[2 + 2]氧化的关键步骤之后,在吡咯烷和氧的存在下,EA通过EI(两性离子样的酚氧基亚胺离子)通过EI生成黄酮醇。EB通过路径II进行,这是由EB与吡咯烷和氧气共同光解而引发的自由基过程,从而生成金酮。初步的机械研究报道。
Metal-free methodology for the preparation of sterically hindered alkynoylphenols and its application to the synthesis of flavones and aurones
作者:Cassandra Taylor、Yuri Bolshan
DOI:10.1016/j.tetlet.2015.05.097
日期:2015.7
A metal-free synthesis for the preparation of sterically demanding ortho-demethylated ynones from mixed anhydrides and potassium alkynyltrifluoroborate salts has been developed. The one-pot reaction proceeds rapidly in the presence of a Lewis acid without the exclusion of air and moisture. This method is advantageous in that it is operationally simple, proceeds under mild conditions, and has a broad
Two series of ten chalcones and ten aurones, where ferrocene replaces the C ring and with diverse substituents on the A ring were synthesized. The compounds were tested against two antibiotic-sensitive bacterial strains, E. coli ATCC 25922 and S. aureus ATCC 25923, and two antibiotic-resistant strains, S. aureus SA-1199B and S. epidermidis IPF896. The unsubstituted compound and those with methoxy substitution showed an inhibitory effect on all bacterial strains at minimum inhibitory concentrations ranging between 2 and 32 mg L−1. For four of these compounds, the effect was bactericidal, as opposed to bacteriostatic. The corresponding organic aurones did not show growth inhibition, underscoring the role of the ferrocene group. The methoxy-substituted aurones and the unsubstituted aurone also showed low micromolar (IC50) activity against MRC-5 non-tumoral lung cells and MDA-MB-231 breast cancer cells, suggesting non-specific toxicity.
作者:B. Cummins、D.M.X. Donnelly、J.F. Eades、H. Fletcher、F.O' Cinnéide、E.M. Philbin、J. Swirski、T.S. Wheeler、R.K. Wilson
DOI:10.1016/s0040-4020(01)98539-4
日期:1963.1
Discrepancies in published work on the alkaline peroxide oxidation of chalcones (AFO reaction) have been examined. It has been found that in addition to flavonols and aurones, 2-benzyl-2-hydroxydihydrobenzofuran-3-ones (IX), and 2-arylbenzofuran-3-carboxylic acids (XV), each new as regards this reaction, appear in the products. A mechanism for the production of these latter compounds is suggested.