黄酮化合物的合成研究进展

黄酮化合物是一类具有多种生物活性的天然产物,其经典的合成方法主要为查耳酮路线和β-丙二酮路线.近年来出现了许多新技术、新方法.本文介绍了2'-羟基查尔酮的氧化关环法、黄烷酮氧化法、改进的Baker-Venkataraman法及其他合成黄酮化合物的方法.     

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。     

苯并咪唑类化合物催化合成的研究进展

苯并咪唑类化合物在医药、农药等方面具有广泛的应用,因此这类化合物合成的新方法备受关注.从合成苯并咪唑类化合物的不同的原料出发,综述了近年来催化合成苯并咪唑化合物的研究新进展.     

黄酮类化合物研究(Ⅷ)——7-取代黄酮及2'''',4-二羟基-3-甲氧基-4''''-取代查尔酮的合成

3,4′,7-三羟基黄酮和3,3′,4′,7-四羟基黄酮是中草药舒冠通糖浆的主要成份,该药对冠心病、心绞痛、胸闷有一定疗效。为系统研究黄酮类化合物的构效关系,我们在前文基础上又合成了5个新的4′-羟基-7-取代黄酮及5个3′-甲氧基-4′-羟基-7-取代黄酮。在此过程中,又合成了4个新的2′,4-二羟基-3-甲氧基-4′-取代查尔酮。其合成路线如下:     

亚胺基吡咯酮类化合物的合成

建立了合成吡咯酮类化合物的新方法,该方法以1,1-烯二胺类化合物(1)和顺丁烯二酸酐(2)为原料,以三乙胺为碱在1,4-二氧六环溶剂中,加热回流,简洁、快速地合成了一系列亚胺类吡咯酮类化合物.产率68%~90%.该方法具有原料易得,操作简单,合成路线简洁等特点.     

8-取代黄酮的合成及生理活性研究

设计合成了8-黄酮甲基氮芥和6种8-黄酮甲基多聚异戊二烯胺类化合物, 产物结构经¹H NMR, MS及元素分析确证. 合成的7个化合物与氮芥类抗肿瘤药物美法仑一起对白血病细胞(K562)、中国仓鼠卵巢细胞(CHO)、黑色素瘤细胞(B16)等3种肿瘤细胞进行了初步的体外生理活性测试. 结果表明, 对3种受测细胞, 8-黄酮甲基氮芥的体外活性均与美法仑接近; N,N-二(8-黄酮甲基)香叶基胺则表现出比美法仑更高的体外抗肿瘤活性.     

2-取代苯并噻唑的合成进展

综述了近十年来2-取代苯并噻唑合成方法的研究成果. 近年来, 无溶剂合成、固相合成、微波促进合成、离子液体为介质的合成以及Pd, Cu, Mn, Sc等新试剂的催化合成都已成为合成此类化合物的有效新方法. 特别是这些新方法的联合使用引起了人们的广泛关注.     

末端羟基炔烃的合成 II. 4-烃基-3-丁炔-1-醇的合成

报道一种以四氢呋喃为起始原料, 合成4-烃基-3-丁炔-1-醇的新方法. 该法完全避免了传统乙炔路线所必须的低温、液氨等苛刻的条件. 鉴于这种炔烃可容易地经还原制得高纯度的指定构型的烯烃, 而许多天然产物如香料(叶醇)、昆虫信息素等都具有这一结构, 因此这一路线为合成这类化合物提供了一个简便、实用的方法.     

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.     

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.     

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．     

Intramolecular excited-state proton-transfer studies on flavones in different environments

The absorption and fluorescence spectra of some biologically active flavones have been studied as a function of the acidity (pH/H0) of the solution. Dissociation constants have been determined for the ground and first excited singlet states. The results are compared with those obtained from Forster-Weller calculations. The acidity constants obtained by fluorimetric titration method are in complete agreement (in most of the systems) with ground state data indicating a excited state deactivation prior to prototropic equilibration. Compared to umbelliferones, flavones are only weakly fluorescent in alkaline solution. This behaviour is explained by the small energy difference between the singlet excited state and triplet excited state giving rise to more efficient intersystem crossing. Most of the flavones studied here undergo adiabatic photodissociation in the singlet excited state indicating the formation of an exciplex or a phototautomer.     

HPLC separation of flavonols, flavones and oxidized flavonols with UV-, DAD-, electrochemical and ESI-ion trap MS detection

The cation-induced or electrochemical oxidation of flavonols has been reported to yield 2-(hydroxybenzoyl)-2-hydroxy-3(2H)-benzofuranone. Two new gradient reversed phase HPLC methods are presented which allow the determination of those oxidized flavonols simultaneously with flavonols and flavones. UV and electrochemical detection are used because of their high sensitivity. Qualitative detection together with quantification of all compounds is achieved with photodiode-array detection. An electrospray ionization ion trap mass spectrometric method is presented for unique identification of the benzofuranones after HPLC separation.     

HPLC separation of flavonols, flavones and oxidized flavonols with UV-, DAD-, electrochemical and ESI-ion trap MS detection

The cation-induced or electrochemical oxidation of flavonols has been reported to yield 2-(hydroxybenzoyl)-2-hydroxy-3(2H)-benzofuranones. Two new gradient reversed phase HPLC methods are presented which allow the determination of those oxidized flavonols simultaneously with flavonols and flavones. UV and electrochemical detection are used because of their high sensitivity. Qualitative detection together with quantification of all compounds is achieved with photodiode-array detection. An electrospray ionization ion trap mass spectrometric method is presented for unique identification of the benzofuranones after HPLC separation.     

Synthesis of a Range of Polyhydroxy 8-Aryl Flavones

The 8-iodo flavones formed by cyclization of benzyl-protected chalcones with iodine in dimethyl sulfoxide have been transformed by a Suzuki coupling reaction into a variety of 8-aryl derivatives. Deprotection with boron tribromide has generated a family of new 8-aryl flavones containing four to eight hydroxyl groups.     

Formal total synthesis of stigmatellin A

An efficient and stereoselective approach for the formal total synthesis of Stigmatellin A has been described. The key steps involved in this synthesis are desymmetrization of the bicyclic olefin to introduce two methyl and two hydroxyl chiral centers, Friedel Crafts acylation, regioselective demethylation, Baker-Venkataraman rearrangement and Grubbs cross metathesis.     

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.