正交试验与响应面法优化微波提取地黄多糖工艺研究（英文）

为了获得微波提取地黄多糖的最佳条件,采用正交试验法和响应面法分别优化微波提取地黄多糖工艺,以地黄多糖得率为指标,采用微波提取地黄多糖,苯酚-硫酸法测定地黄多糖的含量,以微波提取时间、提取温度和料液比进行三因素分析,根据单因素试验结果设计正交试验和响应面试验,进一步优化微波提取地黄多糖工艺。微波提取地黄多糖工艺通过正交试验法优化的结果表明,最佳条件为微波提取时间150 s,提取温度80℃,料液比1 g∶10 mL,该条件下的地黄多糖得率为72.10%。响应面法优化微波提取地黄多糖工艺的结果表明,修正后的最佳工艺条件为微波提取时间137 s,提取温度89℃,料液比1 g∶8 mL,该条件下的地黄多糖得率为74.41%。经过两种优化方法的比较,响应面法适合优化微波提取地黄多糖工艺,能够有效提高地黄多糖得率。     

正交试验结合响应面法优化诃子多糖提取工艺

采用正交试验结合响应面法优化诃子多糖的提取工艺,以诃子多糖的提取率为指标,以固液比、提取温度、提取时间和提取次数为因素,正交试验初步筛选工艺参数,响应面法做进一步优化.结果表明,多糖提取的最佳工艺条件为固液比1∶28,提取温度69℃,提取时间1h,提取次数3次,各项指标相对误差均小于2%,应用响应面法可减少诃子多糖提取时间.     

秦岭龙胆中马钱苷酸提取工艺优化及抗氧化活性研究

对秦岭龙胆中马钱苷酸提取工艺进行优化,并对其抗氧化活性进行测定。利用单因素试验选取最佳因素水平,采用响应面法考察料液比、提取时间、超声频率对秦岭龙胆中马钱苷酸提取率影响。利用清除DPPH及ABTS自由基测定马钱苷酸的抗氧化活性。在分析各个因素的显著性和交互作用后,得到秦岭龙胆中马钱苷酸最佳提取工艺条件为：料液比1∶22、提取时间27 min、超声频率50 kHz,此工艺下的提取率达到0.352%,与预测值0.360%接近。马钱苷酸对DPPH及ABTS自由基均有一定的抗氧化能力,其抗氧化活性高于对照品BHT,且与浓度之间存在量效关系。本研究建立的模型可对秦岭龙胆中马前苷酸提取率进行分析和预测,可为秦岭龙胆的进一步开发和利用提供理论依据。     

正交试验与响应面法优化微波提取地黄多糖工艺研究

为了获得微波提取地黄多糖的最佳条件,采用正交试验法和响应面法分别优化微波提取地黄多糖工艺,以地黄多糖得率为指标,采用微波提取地黄多糖,苯酚-硫酸法测定地黄多糖的含量,以微波提取时间、提取温度和料液比进行三因素分析,根据单因素试验结果设计正交试验和响应面试验,进一步优化微波提取地黄多糖工艺.微波提取地黄多糖工艺通过正交试...     

响应面法优化菊花黄酮超声-微波辅助提取工艺及其抗氧化活性

以黄酮提取率为指标,采用单因素实验结合响应面法优化菊花黄酮的超声-微波辅助提取工艺,并研究了所提菊花黄酮的抗氧化活性.结果表明,菊花黄酮超声-微波辅助提取最佳工艺条件为:乙醇体积分数为76%,料液比为1∶52(g/mL),超声功率为200 W,超声时间为43min.在此工艺条件下,菊花黄酮提取率为10.623%.菊花黄酮对DPPH·和·OH清除能力明显强于BHT,表明菊花黄酮具有较强的抗氧化活性.     

瑶药肿瘤藤多酚提取工艺优化及其抗菌和抗氧化活性分析

为研究肿瘤藤多酚提取工艺及其抗菌和抗氧化活性,本研究采用超声波辅助提取法,确定了甲醇为肿瘤藤多酚最适提取溶剂,在单因素试验基础上通过响应面法优化肿瘤藤多酚的提取工艺,考察了甲醇体积分数、液料比、超声时间三个因素对肿瘤藤多酚提取量的影响。同时,使用总抗氧化试剂盒测定肿瘤藤多酚的抗氧化能力,以抑菌圈、MIC和MBC为指标,采用滤纸片法和连续稀释法研究其抑菌活性。结果表明：肿瘤藤多酚的最佳提取工艺为甲醇水溶液体积分数60%,料液比1∶63(g·mL^-1),超声提取时间88 min;提取量可达11.976±0.47 mg·g^-1。肿瘤藤多酚的抗氧化能力与VC相比,总抗氧化能力较强。且对金黄色葡萄球菌和大肠杆菌具有一定抑制作用,抑菌圈直径分别达到8.13±0.85、1.83±0.35 mm, MIC分别为11.1、3.7 mg·mL^-1,MBC不明显,表明肿瘤藤多酚具有一定的抗氧化和抑菌活性。本研究为肿瘤藤的开发与利用提供了依据。     

超声波法辅助提取‘凤丹’丹皮多糖工艺优化

使用超声波法辅助提取‘凤丹’丹皮中的多糖,对超声波功率、提取温度、提取时间作为三个因素进行试验,以多糖得率为响应面指标,设计响应面对超声波法辅助提取‘凤丹’丹皮多糖工艺进行优化。结果显示丹皮中的多糖的最优提取工艺条件组合为:超声波功率为87.0W,提取温度为43.0℃,提取时间为22.0min。实际测得的丹皮中的多糖的得率为(15.40±0.10)mg·g~(-1)。通过响应面实验与常规方法对比,超声波法对多糖提取有较好的辅助作用,能够提高多糖得率,为‘凤丹’丹皮的资源开发提供依据。     

木蹄多糖提取工艺研究

通过对木蹄多糖提取得率有影响的子实体粉末颗粒大小、料水比、提取温度和提取时间进行的单因素研究,其中对料水比、提取温度和提取时间3个因素采用应用响应面法进行了优化,确定了木蹄子实体多糖的最佳提取工艺条件：子实体粉末颗粒60目,料水比1：42．92,提取温度88．92℃,提取时间3．92h,多糖得率达到5．68％。     

响应面法优化蒙药瞿麦中总生物碱提取工艺研究

研究了响应面法优化蒙药瞿麦总生物碱的最佳提取工艺。采用紫外-可见分光光度法,以总生物碱含量作为评价指标,用Box-Behnken响应面设计考察各因素对其影响,对结果进行二项式拟合及响应曲面分析得到最佳提取工艺。结果表明:蒙药瞿麦中总生物碱的最佳提取工艺为超声温度53℃,料液比1∶31 g/mL,超声时间41 min,超声功率140 W。四因素影响顺序为料液比超声温度超声功率超声时间。此方法简便、快速、灵敏,结果准确可靠,优化后的提取工艺稳定可行,且具有提取率高、提取时间短等优点,对今后的科研工作有一定参考价值。     

响应面法优化苦槛蓝总生物碱提取工艺研究

结合单因素试验和响应面法优化苦槛蓝总生物碱的最佳提取工艺条件,并对其抑菌活性进行研究。以苦参碱为对照品,采用酸性染料比色法,以总生物碱含量为指标,分别考察乙醇体积分数、提取温度、提取时间和料液比4个因素对醇提法提取苦槛蓝总生物碱的影响,在此基础上通过Box-Behnken设计-响应面法确定最佳提取工艺,并进行验证。并检测其大肠杆菌和金黄色葡萄球菌的抑菌活性。苦槛蓝总生物碱的最佳提取工艺为:乙醇体积分数86.18%、提取温度75.42℃、提取时间2.622h、料液比0.080。验证实验下总生物碱提取率为(0.400 6±0.009 2)%,与模型结果接近。苦槛蓝提取物对大肠杆菌的抑菌直径达到33.17±0.53mm,金黄色葡萄球菌抑菌直径达到32.62±0.19mm。Box-Behnken设计响应面法能够有效地优化苦槛蓝总生物碱的提取工艺,并且苦槛蓝总生物碱提取物对大肠杆菌和金黄色葡萄球菌有明显的抑菌效果,这为苦槛蓝生物碱类化学成分的分离及其药理活性的深入研究提供了实验依据。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.