反式-5-甲氧基-3-苯乙烯基吲哚的合成

报道了新化合物反式-5-甲氧基-3-苯乙烯基吲哚的合成方法。氯化苄和三苯基膦在氯仿中回流得到氯化苄基三苯基(1),然后与5-甲氧基吲哚-3-甲醛通过Wittig反应生成目标产物,产物的结构经IR、1HNMR和MS得到确证,纯度99.3%。     

5-甲氧基-2,3-二甲基-1H-吲哚的合成

以5-甲氧基-2-甲基-1H-吲哚为原料,先后经Vilsmeier-Haack反应和还原反应制得标题化合物。5-甲氧基-2-甲基-1H-吲哚与DMF/POCl3反应生成5-甲氧基-2-甲基-1H-吲哚-3-甲醛,该中间体在氰基硼氢化钠/冰醋酸的催化下还原、脱水生成标题化合物,其结构经~1HNMR、~(13)CNMR、MS表征。该合成方法具有原料廉价易得、操作简便易控、反应条件温和、收率高等优点。标题化合物是一种重要的有机合成中间体,广泛用于医药领域。     

褪黑激素(Melatonin)合成的研究

以吲哚为起始原料，经4步反应合成了褪黑激素(MLT)，吲哚I在甲醇中羟基化得到5-羟基吲哚(Ⅱ)(7l％)，Ⅱ与2-氯乙胺在乙酸乙酯中进行胺乙基化反应得到5-羟基色胺(Ⅲ)(73％)，Ⅲ与硫酸二甲酯在甲苯中对羟基进行醚化，得到5-甲氧基色胺(Ⅳ)(78％)，Ⅳ经乙酰化得到产物MLT，收率80％。     

阿比朵尔合成曼尼希反应工艺研究

采用6-溴-5-羟基-1-甲基-2-苯硫甲基吲哚-3-羧酸乙酯为原料,经曼尼希反应合成盐酸阿比朵尔。最佳合成工艺参数为:n(6-溴-5-羟基-1-甲基-2-苯硫甲基吲哚-3-羧酸乙酯)∶n(二甲胺)=1∶3,n(二甲胺):n(甲醛)=2.2∶1,反应时间2 h,反应温度65℃。在此条件下,收率为83%以上,纯度为99.0%以上。     

6-溴-2-溴甲基-5-羟基-1-甲基吲哚-3-羧酸乙酯的合成工艺研究

采用5-乙酰氧基-1,2-二甲基吲哚-3-羧酸乙酯和溴素为原料,于四氯化碳中,在过氧化苯甲酰催化下,合成6-溴-2-溴甲基-5-羟基-1-甲基吲哚-3-羧酸乙酯,HPLC进行跟踪检测。采用正交设计研究确定了最佳合成工艺参数为:物料比1为n(5-乙酰氧基-1,2-二甲基吲哚-3-羧酸乙酯)∶n(四氯化碳)=1∶18.3,物料比2为n(5-乙酰氧基-1,2-二甲基吲哚-3-羧酸乙酯)∶n(溴素)=1∶2.84,反应时间5 h,反应温度45℃。在最佳条件下收率为84.6%,纯度为98%以上,达到了优化的目的。     

5-甲氧基吲哚的合成

介绍了5-甲氧基吲哚在药物合成中的重要用途,叙述了5-甲氧基吲哚的主要合成方法,采用了以吲哚为原料,经2-磺酸钠-1-乙酰基-二氢吲哚半水合物和5-溴吲哚中间体的合成路线,合成了标题化合物5-甲氧基吲哚。产品进行了纯化和结构鉴定。产品纯度达98%以上,反应总收率50%以上。     

褪黑素合成及环化机理研究

以邻苯二甲酰亚胺钾盐为起始原料,经五步反应合成了褪黑素,鉴定了产物结构,合成收率达35.6%,纯度99.1%。对中间产物2-羧乙酯基-3-(2-邻苯二甲酰亚胺乙基)-5-甲氧基-吲哚的环化反应过程进行了机理研究,为最佳工艺条件的确定提供了理论依据。     

吲哚洛尔的合成及结构分析

4-羟基吲哚、环氧氯丙烷在氢氧化钠的乙醇溶液中反应生成中间体1-(1H-吲哚-4-氧基)-3-氯-2-丙醇,然后中间体与异丙胺反应,合成出了目标产物吲哚洛尔{1-(1H-吲哚-4-氧基)-3-[(1-甲基乙基)氨基]-2-丙醇}。通过~1H NMR、~(13)C NMR、IR对合成的吲哚洛尔进行表征,结果表明与理论结构一致。     

K2CO3促进3-亚烷基氧化吲哚与1-硝基丙烷选择性Michael加成及加成-消除反应

报道了一种K_2CO_3促进的3-亚烷基氧化吲哚与1-硝基丙烷选择性Michael加成及加成-消除反应。3-亚烷基氧化吲哚N-取代基对产物具有控制作用,无取代的3-亚烷基氧化吲哚与1-硝基丙烷反应生成加成产物,N-保护基的3-亚烷基氧化吲哚与1-硝基丙烷反应则生成单一构型的加成-消除产物。确定最佳的合成条件为:溶剂为甲苯,碱为K_2CO_3,室温,n(3-亚烷基氧化吲哚)∶n(1-硝基丙烷)∶n(K_2CO_3)为1.0∶1.0∶1.0。该反应在室温下反应数小时得到两类不同的3-取代氧化吲哚衍生物,合成方法具有简单高效、条件温和、底物适用范围广等优点。     

9H-吲哚[4,5-b]并嘧啶类衍生物的合成研究

7-甲(乙)基吲哚酮(1a,1b)与制备好的Vilsmeier-Haack试剂反应合成2-氯-3-甲酰基-7-甲(乙)基吲哚(2a,2b)和2-氯-3-乙酰基-7-甲(乙)基吲哚(3a,3b);将2a,2b,3a,3b N甲基化得4a-4b,5a-5b,再将以上化合物与硝酸胍反应,以良好的收率合成吲哚并嘧啶类化合物(6a-6b,7a-7b),在此基础上探究与氨基胍反应尝试得到闭环化合物。以上制备过程具有反应条件温和、后处理简单等优点,为制备吲哚并嘧啶类化合物提供了简单方法。     

The antioxidant capacity of complex mixtures by kinetic analysis of crocin bleaching inhibition

The capability of a compound or of a mixture of compounds to quench peroxyl radicals was measured by analyzing the kinetics of the competition of a parallel reaction where peroxyl radicals bleach the carotenoid crocin. This kinetic approach, originally described for the analysis of antioxidants reacting with hydroxyl radicals in water, was modified by both decreasing the polarity of the solvent, thus allowing the analysis of lipophilic compounds, and by substituting a source of peroxyl radicals for the hydroxyl radical generating system. Single compounds as well as complex mixtures were analyzed by kinetic data processing. Overall antioxidant capacity, relative to that of α-tocopherol or of its soluble analog Trolox C, was calculated. As examples of the use of this test, the antioxidant capacities of a crude rosemary extract, Maillard reaction products, and virgin olive oils were measured.     

Aromatic Products from Reaction of Lignin Model Compounds with UV-Alkaline Peroxide

A series of guaiacyl and syringyl lignin model compounds and their methylated analogues were reacted with alkaline hydrogen peroxide while irradiating with UV light at 254 nm. The aromatic products obtained were investigated by gas chromatography-mass spectrometry (GC-MS). Guaiacol, syringol and veratrol gave no detectable aromatic products. However, syringol methyl ether gave small amounts of aromatic products, resulting from ring substitution and methoxyl displacement by hydroxyl radicals. Reaction of vanillin and syringaldehyde gave the Dakin reaction products, methoxy-1,4-hydroquinones, while reaction of their methyl ethers yielded benzoic acids. Acetoguaiacone, acetosyringone and their methyl ethers afforded several hydroxylated aromatic products, but no aromatic products were identified in the reaction mixtures from guaiacylpropane and syringylpropane. In contrast, veratrylpropane gave a mixture from which 17 aromatic hydroxylated compounds were identified. It is concluded that for phenolic lignin model compounds, particularly those possessing electron-donating aromatic ring substituents, ring-cleavage reactions involving superoxide radical anions are dominant, whereas for non-phenolic lignin models, hydroxylation reactions through attack of hydroxyl radicals prevail.     

丝素蛋白酶解多肽的抗氧化性研究

文章以广西宜州废蚕丝为原料,探讨了丝素蛋白酶法水解产物的抗氧化活性.结果显示,丝素蛋白溶液在酶解3.5小时,对二苯代苦味酰基（DPPH·）和羟基自由基（·OH）的清除率达最佳,分别为35.24％和60.59％;对超氧自由基（O2-·）的清除率在4小时达到最佳,为25.37％.丝素蛋白的酶解产物具有良好的抗氧化活性.     

荧光法测定镧银二氧化钛无机纳米复合材料中的羟基自由基

目的 为了增进TiO2光催化材料的实用性,使其在药学、生物学、医学以及免疫学等领域可以广泛应用,采用掺杂稀土元素镧,提高其光催化性能.方法 应用苯基荧光酮荧光法,通过测定苯基荧光酮反应前后的荧光变化,间接地测定自由基的产生,找到体系的最佳实验条件,方法简单,测定快捷,灵敏度高,无需昂贵的仪器,可作为一种筛选抗氧化剂的方法,研究稀土元素掺杂二氧化钛所产生的羟基自由基.结果 合成出了具有优异抗菌活性和光学活性的新型纳米抗菌剂,苯基荧光酮荧光法测定出La-Ag-TiO2体系中产生的羟基.结论 双元素掺杂的样品的荧光强度在一定条件下低于单元素掺杂的样品,由此可知,双元素掺杂的样品产生的羟基自由基多于单元素掺杂,且镧的掺杂促进了羟基自由基的产生,降低了样品的荧光强度.     

大孔吸附树脂分离纯化猪毛菜总黄酮及其抗氧化活性

采用不同大孔吸附树脂分离纯化猪毛菜总黄酮,并对纯化后的总黄酮进行体外抗氧化活性测试。通过考察影响树脂静态和动态吸附与洗脱的主要因素,确定猪毛菜总黄酮分离纯化优化工艺条件。静态吸附实验表明,AB-8树脂分离纯化效果较好,并且吸附符合Langmuir和Freundlich方程。动态吸附和解吸的最佳工艺条件为:上样液质量浓度1.25 g/L、p H=4.5、上样流速2 m L/min、上样量2.5 BV(BV指树脂柱内装载树脂的体积)、洗脱剂为体积分数80%的乙醇溶液、洗脱流速1.0 m L/min,洗脱剂用量4 BV。所得洗脱液中黄酮质量分数从纯化前10.20%增加到纯化后51.89%,回收率为84.43%。体外实验表明,纯化后的黄酮可以清除羟自由基和超氧阴离子自由基,并有较好的还原力。纯化后的黄酮可以作为一种潜在的天然抗氧化剂。     

The antioxidant properties of lycopene concentrate extracted from tomato paste

Lycopene concentrate (LC) containing 50 wt% lycopene was extracted from tomato paste. The antioxidant properties of LC were evaluated by means of chemiluminescence in four models. The four models were superoxide anions generated from pyrogallol autoxidation, hydroxyl radicals from Fenton reaction, singlet oxygens from OH⁻−NaClO−H₂O₂, and lipid peroxidation from 2,2′-azobis(2-amidinopropane)dihydrochloride-induced γ-linolenic acid. LC was an effective scavenger toward superoxide anions, hydroxyl radicals, and singlet oxygens, and also it could effectively reduce lipid peroxidation. The 50% efficient concentrations (EC₅₀) toward superoxide anions, hydroxyl radicals, lipid peroxidation and singlet oxygen were 0.75, 0.05, 0.1, and 1 mg/mL, respectively. In addition, changes of antioxidant behaviors with time were investigated. The time requirements of LC for effectively scavenging superoxide anions, hydroxyl radicals, and inhibiting lipid peroxidation were not higher than 6, 6, and 18 s, respectively.     

Is Measuring OH. Radical Scavenging a Reasonable Measurement of Antioxidant Properties?

The measurement of the hydroxyl radical scavenging properties of a compound is not indicative on its antioxidant properties in vivo. To get such information one has to elucidate the mechanism of its reaction with typical secondary radicals, mainly typical RO₂^. radicals and to some degree with R^. radicals. Elucidation of the mechanisms of reaction is essential before a conclusion regarding the antioxidant properties can be derived. One should remember that in vivo even vitamins C and E might act as pro-oxidants.     

Inhibition of 2,2′-azobis(2,4-dimethylvaleronitrile)-induced lipid peroxidation by sesaminols

We found that sesaminols, a mixture of sesaminol and its stereoisomers, are potent inhibitors of the oxidation of low-density lipoprotein induced by 2,2′-azobis(2,4-dimethylvaleronitrile). Although sesaminols strongly inhibit lipid peroxidation related to their ability to scavenge free radicals, their antioxidant effects have not been investigated. To confirm the involvement of the phenolic moiety in the sesaminol structure in antioxidant activity, sesaminols were reacted with 2,2′-azobis(2,4-dimethylvaleronitrile). The reaction products were isolated by high-performance liquid chromatography and found to have a 1-cyano-1,3-dimethyl-butyl-peroxyl group in their structures. These chemical structures suggest that the sesaminols reacted with the alkylperoxyl radicals to form four major reaction products that are stereoisomers of each other, although the stereochemistry of each isomer has not yet been confirmed. Further instrumental analyses of the reaction products may increase our understanding of the antioxidant activity of sesaminols.     

芳基二氢萘类木脂素的不对称合成研究进展

天然木脂素是由含酚羟基的苯丙素类化合物在生物酶催化下,通过氧化偶联反应而形成的。因此,以氧化偶联反应为关键步骤来仿生合成各类木脂素是最常用也是最快捷的合成途径。文章将就如何利用氧化偶联反应,在生物体外进行简单快捷的构建芳基萘类木脂素的基本骨架结构展开相关论述。     

Optimization of microwave-assisted enzymatic extraction of polyphenols from waste peanut shells and evaluation of its antioxidant and antibacterial activities in vitro

A microwave-assisted enzymatic extraction (MAEE) method was developed and optimized to enhance the polyphenols extraction yield from waste peanut shells. The optimum conditions were as follows: irradiation time 2.6 min, amount of cellulase 0.81 wt.%, a pH of 5.5, and incubation at 66 °C for 2.0 h. Under these conditions, the extraction yield of total polyphenols could reach 1.75 ± 0.06%, which was higher than other extraction methods including heat-refluxing extraction, ultrasonic-assisted extraction and enzyme-assisted extraction. The structural changes of the plant material after different extractions observed by scanning electron microscopy provided visual evidence of the disruption effect. Moreover, the crude extract was then purified by NKA-9 resin, the polyphenols content in the purified extract increased to 62.73%. The antioxidant activities of the crude and purified polyphenols extract were evaluated by DPPH and hydroxyl radicals, reducing power and β-carotene bleaching test. The antibacterial activities of purified extract were also tested using Oxford cup method. The results indicated that the MAEE method was efficient and environment-friendly, and the polyphenols have significant antioxidant and antibacterial activities, which can be used as a source of potential antioxidant and preservative.