黄酮化合物的合成新方法

黄酮类化合物具有广泛而重要的生物活性和药理作用,其化学合成研究受到普遍重视.经典的合成方法主要是查耳酮路线和β-丙二酮路线.近年来有很多新技术、新方法在黄酮化合物合成中得到了巧妙的应用.对近年来出现的新的改进的Baker-Venkataraman法、催化羰基化闭环法以及其他合成黄酮化合物的新方法作了介绍.     

黄酮-6-羧酸类化合物的合成、表征和抑菌活性

通过查尔酮路线合成了6种黄酮-6-羧酸化合物,采用I2/DMSO为氧化剂通过微波辐射合成了其中3种黄酮羧酸.所有化合物的结构通过NMR,IR和元素分析方法进行了表征,并采用X射线单晶衍射法进一步测定了黄酮-6,4'-二羧酸的晶体结构.初步生物活性试验结果表明,6种化合物对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌均有一定的抑制作用.     

黄酮醇类化合物的合成研究进展

黄酮醇即3-羟基黄酮,是一类独特的黄酮化合物,广泛存在于植物界中,具有许多重要的生物活性和药理作用,其化学合成研究一直备受关注.综述了黄酮醇骨架的4种主要合成方法:Auwers法,查尔酮氧化关环即Algar-Flynn-Oyamada(AFO)反应,Baker-Venkataraman法,黄酮DMDO(3,3-二甲基双环氧乙烷)氧化法;并对多羟基黄酮醇的区域选择性甲基化、异戊烯基化和糖苷化等衍生化方法进行了概述.     

B-失碳-3,5-环谷甾烷-6-羟基-6-甲酸及B-失碳-3,5-环谷甾烷-6-酮的合成

油菜甾醇内酯(brassinolide,1)是从油菜花粉中分离到的一种新型高效植物生长激素.自1979年确定其结构以来,一些实验室先后成功地进行了合成.尽管这些合成路线各有特点,但在B环内酯的建立上,大都采用了Baeyer-Villiger方法氧化6-酮化合物的路线;该方法在生成预期的B-高6-酮-7-氧化合物的同时,得到了约15％的7-酮-6-氧化合物异构体.     

柚皮苷半合成生物活性黄酮醇和橙酮类化合物研究

以柚皮苷为原料,经过糖苷水解、脱氢、苄基保护、O-甲基化、过氧丙酮(DMDO)氧化或阿尔格-弗林-大山田(Algar-Flynn-Oyamada)反应和脱苄基保护等反应步骤,半合成了山萘酚(1,Kaemferol),5,7,4’-三甲氧基黄酮醇(2)、3,5-二羟基-7,4’-二甲氧基黄酮醇(3),鼠李柠檬素(4,Rhamnocitrin)等4种天然黄酮醇类和4,6,4’-三羟基二氢橙酮(5)、4-羟基-6,4’-二甲氧基二氢橙酮(6)两种新的橙酮类化合物.重点探讨了过氧丙酮(DMDO)直接氧化黄酮制备黄酮醇和Algar-Flynn-Oyamada反应制备橙酮的合成方法,改进优化了反应条件.所有合成化合物的结构已通过1H NMR,MS和IR等波谱方法进行了确认.该合成途径原料易得,工艺简便,收率较高,具有较高的应用价值.     

黄酮化合物的合成——推荐一个大学有机化学实验

以苯酚为原料,采用Baker-Venkataraman重排法合成黄酮化合物2-苯基苯并吡喃酮。实验内容包括成酯反应、Fries重排、Claisen缩合,实验操作包括水蒸气蒸馏、减压蒸馏、重结晶、熔点测定、薄层色谱、红外光谱和核磁共振图谱的解析等。该实验合成路线成熟,产物收率高,产品易于纯化。     

黄酮苷的合成研究进展

黄酮苷广泛存在于自然界植物,具有广泛的药理活性和潜在的药用价值,其合成方法值得研究,对2014年至2018年黄酮苷的合成进行综述.黄酮苷的合成主要包括化学合成和生物合成两大类,而化学合成又分为全合成和半合成,其中全合成主要有β-丙二酮酸化关环法(Baker-Venkataraman,BK-VK法)和查尔酮氧化关环法(Algar-FlynnOyamada, AFO法)两种经典方法;半合成是以芦丁、槲皮素、山萘酚、柚皮素等天然黄酮为原料.黄酮氧苷的化学合成目前常用的方法有三种:Koening-Knorr法、相转移催化法、糖基三氯乙酰亚胺酯法.黄酮碳苷的糖苷链的连接主要是通过O→C重排法.酶催化生物合成法目前常用的酶是糖基转移酶和糖苷合酶这两种酶.     

双环吡咯酮类化合物的简便合成

建立了一锅法合成双环吡咯酮化合物的方法.该方法以杂环烯酮缩胺1为合成砌块,在1,4-二氧六环溶剂中,三乙胺作碱,与乙二醛在50℃下反应,一步法关环合成了双环吡咯酮类化合物3a~3i.该方法具有合成路线简洁、后处理简单、原料易得、产率高和操作简便等优点.     

3-羟基-6-O-甲基红霉素的氧化

3-酮基-红霉素化合物是合成酮内酯化合物的关键中间体,由相应的3-羟基红霉素化合物氧化得到.本文对3-羟基-6-O-甲基红霉素(Ⅱ)生成3-酮基化合物(Ⅴ)的氧化反应进行了研究.Ⅱ经乙酰化、碳酸酯化保护后,采用五氧化二磷(P2O5)和乙酸酐(Ac2O)作为活化剂的二甲基亚砜法对其氧化.结果表明,两者在室温下,即能将保护后的Ⅱ转化为目标化合物Ⅴ.Ⅴ的得率分别为85.8%和78.3%.这两种氧化方法成本低、安全性好、环境友好并容易操作,具有规模化生产的前景.     

Dess-Martin氧化剂制备方法的改进

Dess-Martin氧化剂是非常重要的氧化剂,在有机合成化学中常被用于将羟基化合物氧化为醛或酮.Dess-Martin氧化剂的制备需要严格的无水无氧操作,介绍了以邻碘苯甲酸为原料合成Dess-Martin氧化剂的新方法和实验室合成路线的探索与改进.     

Synthesis and properties of 3-acyl-γ-pyrones, a novel class of flavones and chromones

Using modified Baker-Venkataraman reaction a novel class of 3-acyl flavones and chromones have been synthesised. Reaction mechanism for their formation have been elucidated. The properties of 3-acyl flavonoids indicate them to be precursors for the synthesis of flavones.     

黄酮类化合物合成的研究进展

黄酮是一类具有抗炎,抗菌,抗病毒等作用的化合物．本文综述了黄酮类化合物的重要合成方法及其最新发展．     

First total synthesis of topopyrone C

The first synthesis of topopyrone C, a natural compound and inhibitor of Topoisomerase I, has been carried out by Marschalk alkylation of 1-hydroxy-3,6,8-trimethoxyanthraquinone, followed by a Baker-Venkataraman chain elongation and an acid-catalyzed cyclization for the construction of the pyrone ring.     

Judicious application of allyl protecting groups for the synthesis of 2-morpholin-4-yl-4-oxo-4H-chromen-8-yl triflate, a key precursor of DNA-dependent protein kinase inhibitors

[Structure: see text] 2-morpholin-4-yl-4-oxo-4H-chromen-8-yl 2,2,2-trifluoromethanesulfonate is a key intermediate for the synthesis of the DNA-dependent protein kinase (DNA-PK) inhibitor 8-dibenzothiophen-4-yl-2-morpholin-4-yl-chromen-4-one (NU7441). Two improved methods for the synthesis of this triflate have been developed: (A) in 35% overall yield, through modification of the published route, and (B) in 15% overall yield, by a new route employing a Baker-Venkataraman rearrangement to enable generation of the chromenone scaffold. Both syntheses depend on the judicious use of allyl protecting groups.     

(+)-Apollineanin: a new flavanone from Tephrosia apollinea

Chemical investigation of the leaves of Tephrosia apollinea has yielded a new flavanone named (+)-apollineanin, together with two known flavones: (-)-semiglabrin and (-)-semiglabrinol. The structure of the new compound was determined on the basis of mass, 1D and 2D NMR spectroscopies including NOE difference spectroscopy. The absolute stereochemistry of (+)-apollineanin was determined by Mosher ester methodology and from CD data.     

基于浊点提取悬铃木球叶中黄酮化合物的研究

采用微波辅助浊点提取悬铃木球叶中的黄酮类化合物。在单因素试验的基础上,0.6%吐温-80的乙醇溶液作为浊点萃取剂,通过响应面法优化确立悬铃木黄酮类化合物的最佳提取工艺条件：微波功率410 W,提取时间7 min,液料比49:1 mL?g_^-1,实际测得黄酮平均得率1.480 mg?g_^-1。并对黄酮类化合物进行了分离纯化,得到2个化合物,经理化常数测定和波谱解析鉴定,化合物1为3,5,7-三羟基黄酮,分子式为C₁₅H₁₀O₅;化合物2为山奈酚,分子式为C₁₅H₁₀O₆。     

Myeloperoxidase inhibitory and radical scavenging activities of flavones from Pterogyne nitens

Two new flavone glucosides, nitensosides A and B (1, 2), together with four known compounds, sorbifolin (3), sorbifolin 6-O-beta-glucopyranoside (4), pedalitin (5), and pedalitin 6-O-beta-glucopyranoside (6) were isolated from Pterogyne nitens. Their structures were elucidated from 1D and 2D NMR analysis, as well as by high resolution mass spectrometry. All the isolated flavones were evaluated for their myeloperoxidase (MPO) inhibitory activity. The most active compound, pedalitin, exhibited IC50 value of 3.75 nM on MPO. Additionally, the radical-scavenging capacity of flavones 1-6 was evaluated towards ABTS and DPPH radicals and compared to standard compounds quercetin and Trolox.     

Phytochemical constituents from dietary plant Citrus hystrix

Chemical investigation of the fruit peel of dietary plant Citrus hystrix offered two new flavones 5,6,4′-trihydroxypyranoflavone I and 5,4′-dimethyl-6-prenylpyranoflavone XIII besides 11 known compounds. The structures of all compounds were elucidated with the aid of suitable analytical methods like 1D, 2D-NMR, mass and single crystal X-ray analysis. An X-ray crystal study of compound II was done for the first time and the compounds I–VI, XI and XII are hitherto not reported from this plant. Biological studies revealed that compound I found to have a good antidiabetic and antiacetylcholinesterase activities meanwhile compounds II, III and V showed a significant free radical scavenging ability as well as antioxidant capacity. In addition, compounds I, IV, V and VI showed cytotoxicity against U87, A549 and MCF-7 cells. Overall, the new compound I showed valuable bioactive properties. Due to insufficient quantity of compound XIII, biological studies were not done.     

Facile Synthesis of 5-Hydroxy-2-（2-phenylethyl）chromone

5-Hydroxy-2-(2-phenylethyl)chromone(1) was synthesized from 2,6-dihydroxyacetophenone(7) obtained via four-steps resorcinol-reacting with phenylpropionic acid,the procedures involved are Baker-Venkataraman rearrangement and cyclization which are easy to conduct,the overall yield is 32%.