新疆藁本挥发油的抑菌活性及组分分析

为了明确中药材新疆藁本挥发油对植物病原真菌的熏蒸抑制活性及分析其化学组分,为新疆藁本挥发油在农业上的应用提供参考依据。采用水蒸气蒸馏法提取新疆藁本挥发油,通过生长速率法测定其挥发油对小麦赤霉病菌、水稻胡麻斑病菌、草莓灰霉病菌和苹果炭疽病菌4种植物病原真菌的熏蒸抑制作用,并利用气质联用仪(GC-MS)分析新疆藁本挥发油的化学组分。结果表明,新疆藁本挥发油对供试的4种植物病原真菌均有强烈的熏蒸抑制作用,有效中浓度(EC_(50))分别为0.98、1.01、1.46、2.79μL/皿。GC-MS从新疆藁本挥发油中共检测到23个组分,鉴定出其中17个,占挥发油总量的99.796%,其主要组分为肉豆蔻醚(94.328%)、2-莰烯(3.018%)等。新疆藁本挥发油可作为抑制植物病原真菌的天然活性成分资源,开发利用。     

GC-MS联用分析三个品种杨梅树叶的挥发油组分

采用气相色谱-质谱联用技术对木叶、黑炭、东魁3个品种杨梅树叶中的挥发油进行分析比较.3种杨梅树叶挥发油中共检出14种相同成分,这些共有成分的相对含量分别占木叶梅叶、黑炭梅叶和东魁梅叶挥发油总相对含量的53. 3%、48. 4%、55. 15%.3种杨梅树叶挥发油中均舍有多种萜烯,对杨梅果实具有一定抗菌保鲜作用.东魁杨梅树叶挥发油萜烯含量最高,这可能是东魁杨梅果实保鲜期较长的原因;木叶杨梅叶含的特殊香味成分的含量较高,这可能是木叶梅果实香气最浓郁的原因.     

麻叶千里光挥发油抗病毒活性及成分分析

利用体外细胞病变效应(CPE)法,发现菊科千里光属植物麻叶千里光(Senecio cannabifoliusLess.)挥发油对呼吸道合胞病毒(RSV)和单纯疱疹病毒Ⅰ型(HSV-Ⅰ)致HeLa细胞病变有显著的抑制作用,能不同程度地延缓副流感病毒、柯萨奇病毒B3、腺病毒Ⅲ型和流感病毒致细胞病变作用。为进一步确定麻叶千里光挥发油抗病毒的活性成分,经气相色谱-质谱联用技术对其进行了成分分析。麻叶千里光挥发油得率0.22%(mL/100g),从中初步鉴定了26种化合物,占挥发油总量的88.47%,主要为正十六(烷)酸(27.01%)、胡萝卜次醇(13.73%)、9,12-十八碳二烯酸(9.99%)、α-蒎烯(9.28%)和β-蒎烯(5.58%)。在鉴定出的化合物中,萜烯占47.42%,脂肪酸类占37.61%,其它成分仅占3.44%,故提示麻叶千里光挥发油中高含量的萜烯和脂肪酸类可能与其抗病毒活性有关。     

喹啉-多胺衍生物的合成及其活性评价

设计合成了13个喹啉-多胺衍生物,产物结构均经1H NMR,ESI-MS和元素分析确认.采用噻唑蓝(MTT)法测试了化合物对连二亚硫酸钠损伤肾上腺嗜铬细胞瘤(PC12)细胞的抑制作用,结果表明所有目标化合物对PC12细胞损伤均有较好的抑制作用,部分化合物优于尼莫地平,其中化合物T6和T7的活性最强,10μmol/L浓度下损伤抑制率分别为28.04%和27.58%.     

紫罗兰花挥发油化学成分分析及其在卷烟加香中的评价

研究紫罗兰花挥发油的挥发性成分及其卷烟加香效果。采用同时蒸馏萃取法提取紫罗兰花挥发油,利用气相色谱—飞行时间质谱(GC-TOFMS)联用技术对其化学成分进行分离鉴定,采用峰面积归一化法计算各个组分相对含量,并将其加入卷烟中进行感官评吸。共鉴定了66个化合物,占检出化合物总量的79.03%,主要成分为2-β-蒎烯(13.28%)、3-蒈烯(10.16%)、(-)-异喇叭烯(4.80%)、β-波旁烯(4.53%)、斯巴醇(3.39%)和β-杜松烯(3.29%)等;评吸结果发现:适量浓度的紫罗兰挥发油能提高卷烟整体的协调性,提升卷烟的香气质和香气量,降低对口腔、鼻腔的刺激性,减少杂气,回味甜香,余味清爽。紫罗兰挥发油中化学成分丰富,主要为萜类及其含氧衍生物,其中,许多化合物具有芳香性和药用活性。     

兴安落叶松针叶挥发油的GC-MS和启发渐进式特征投影法分析

采用水蒸气蒸馏法提取兴安落叶松针叶挥发油,利用气相色谱.质谱(GC-MS)联用对挥发油进行成分测定,并对其重叠色谱峰采用启发渐进式特征投影(HELP)法进行分辨,得到各组分的纯色谱峰和质谱,然后采用峰面积归一化法确定各化合物的相对含量.共分离出110种化合物,鉴定了70种化合物,占挥发油总量的93.09%,其中单萜、倍半萜和二萜的含量分别为31.92%、53.29%和6.91%.     

碧桃花、叶、茎、果实挥发油成分及抗油脂氧化、抑菌作用

采用超临界CO₂萃取,应用气相色谱-质谱联用(GC-MS) 法鉴定碧桃花、叶、茎、果实挥发油中化学成分和相对质量浓度,共鉴定178个化合物。 其中花挥发油中主要成分有苯甲醛(11.42%)、α-金合欢烯(9.18%)、十六烷酸(8.03%)。叶挥发油中主要成分有:苯甲醛(14.72%)、二十五烷(9.85%)、二十八烷(8.29%)、二十三烷(5.14%)。 茎挥发油中主要成分有(Z)-3-己烯-1-醇(28.90%)、(E)-2-己烯醇(16.06%)、正己醇(6.86%)。 果实挥发油中主要成分有:苯甲醛(20.46%)、十六烷酸(5.84%)、苯甲醇(5.01%)。 在10~40 d贮藏期内,花、叶、茎、果实挥发油可明显降低花生油的过氧化值和酸值,其中以茎挥发油高剂量组降低作用最强。 花和茎挥发油具有较强的抑菌作用,其最小抑菌浓度(MIC)值在0.024~0.188 g/L范围内。     

4-二甲氨基黄酮衍生物的合成及其活性评价

设计合成了10个4-二甲氨基黄酮衍生物,产物结构均经1H NMR,ESI-MS和元素分析确认.采用噻唑蓝(MTT)法测试了化合物对HepG2(人肝癌细胞)的抑制作用,结果表明目标化合物在30μmol/L浓度下对HepG2细胞损伤均有一定的抑制作用,大部分化合物优于对照药物槲皮素,其中化合物5c,5e,5f和5j活性最强,抑制率分别为91.0%,90.1%,95.7%和92.1%,而且化合物5f在10μmol/L浓度下对HepG2的抑制率为93.1%,具有深入研究的价值.     

几种天然植物提取物对酪氨酸酶活性的抑制作用

选择合适的溶剂体系,用维生素C(Vc)作为阳性对照物,采用分光光度法测定了不同浓度的茶多酚、丹皮酚及金银花叶子总黄酮提取物(乙酸乙酯相)对酪氨酸酶活性的抑制作用.结果表明:采用1%丙三醇和1%吐温-80(体积比1∶1)混合液作溶剂可显著增加丹皮酚和金银花叶子总黄酮提取物在水中的溶解度;茶多酚、丹皮酚、金银花叶子总黄酮提取物对酪氨酸酶的活性都有一定的抑制作用,其抑制作用从强到弱依次为Vc、Vc∶丹皮酚=1∶2(质量比)、Vc∶丹皮酚=1∶1(质量比)、茶多酚、茶多酚∶丹皮酚=2∶1(质量比)、丹皮酚、金银花叶子总黄酮提取物.     

气相色谱-质谱技术分析红松松塔挥发性成分

采用水蒸气蒸馏法,对红松松塔挥发性成分进行提取和研究,最佳蒸馏时间5.5 h,挥发油提取率1.28%.利用气相色谱-质谱联用技术对提取的挥发油成分进行分析,共鉴定出32种化学成分,主要为单萜和倍半萜类化合物,其中相对含量较高的有α-蒎烯(44.258%)、D-柠檬烯(23.426%)、β-蒎烯(8.674%)、石竹烯(3.462%)、β-月桂烯(3.018%)等.研究结果表明红松松塔挥发油中富含α-蒎烯、D-柠檬烯、石竹烯等多种具有药理活性的成分.因此,红松松塔是一种具有较好前景的天然药用资源.     

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.