海洋微藻培养液中二甲基硫与二甲基硫丙酸的同步分析

基于水体中二甲基硫(DMS)的固相微萃取-气相色谱-质谱联用分析方法,建立了海洋微藻培养液中DMS、溶解态二甲基硫丙酸(DMSPd)和颗粒态二甲基硫丙酸(DMSPp)的同步测定方法. 结果表明: 本方法在0.01～10.0 μg/L 范围内线性良好, 方法检出限10.6 pg , 加标回收率为(93.1±1.3)%; 相对误差范围小于5%.将4种微藻培养液高速离心,上层和下层溶液分别加固体NaCl后立即测定DMS,加NaOH 溶液反应12 h后测定DMS含量, 根据其数值的差值可得到各微藻培养液中DMS与DMSP的含量.检出结果与文献报道具有相似的结论:甲藻和定鞭藻是DMS(P)的重要生产者.其中颗石藻 (Pleurochrysis carterae)单位细胞DMSPp 的检出含量为(13.8±0.9)pg/cell.     

韭菜有机溶剂提取液的气相色谱-质谱分析及其对香蕉枯萎病菌的抑制作用研究

采用气相色谱-质谱法对韭菜茎和叶的石油醚、三氯甲烷、二氯甲烷、丙酮、乙酸乙酯有机溶剂提取液进行了检测.结果表明:有机溶剂提取液中有二甲基二硫、二甲基三硫、甲基甲烷硫代磺酸盐、二甲基酯硫磺酸、甲基2-丙烯基二硫及杂环等多种含硫化合物,另外还检出较复杂的3-乙烯基-1,2-二硫代杂环己-5-烯类物质.低温条件下,茎中石油醚...     

表面解吸常压化学电离质谱直接测定香辛蔬菜化学指纹

采用表面解吸常压化学电离质谱技术在无需样品预处理的前提下,对香辛蔬菜如韭菜、洋葱和大蒜的挥发性成分进行了快速检测,并对部分成分进行了二级串联质谱分析。 结果表明,韭菜叶片挥发性主要成分为2-甲基-2-戊烯、二甲基硫代亚磺酸酯、甲基烯丙基硫代亚磺酸酯等,其中二甲基硫代亚磺酸酯和甲基烯丙基硫代亚磺酸酯产生较强的M+H2O·+信号。 未切开的洋葱鳞茎挥发性成分质谱信号较弱,质谱图中主要是一些电晕放电产生的初始离子信号。 切开后的洋葱鳞茎挥发性成分质谱信号明显增强,主要是丙烯基次磺酸、丙基烯丙基硫代亚磺酸酯和二丙基硫代亚磺酸酯。 大蒜鳞茎挥发性成分主要是二烯丙基硫代亚磺酸酯。 切开后的大蒜鳞茎挥发性成分主要是丙烯基次磺酸。 实验对韭菜的二甲基硫代亚磺酸酯和甲基烯丙基硫代亚磺酸酯、洋葱的丙烯基次磺酸、大蒜的二烯丙基硫代亚磺酸酯进行了二级串联质谱分析。 表面解吸常压化学电离质谱技术无需样品预处理,分析速度快且对样品不造成破坏。     

反式硫代环磷酰基硫脲的合成及性质研究

采用反式２－异硫氰式－４－基基－５，５－二甲基－２－硫代－１，３，２－二氧磷杂环己烷与不同胺的加成反应合成了１３个的反式环状硫代磷酰基硫脲衍生物，生物活性初步测试表明，部分化合物具有杀菌及植物生长调节活性，本文首次报道了２－氯－苯基－５，５－二甲基－２－硫代－１，３，２－二氧磷杂环己烷与硫氰酸钾反应的立体化学。     

表面解吸常压化学电离质谱快速测定香辛蔬菜化学指纹

采用表面解吸常压化学电离质谱技术在无需样品预处理的前提下,对香辛蔬菜如韭菜、洋葱和大蒜的挥发性成分进行了快速检测,并对部分成分进行了二级串联质谱分析。结果表明,韭菜叶片挥发性主要成分为2-甲基-2-戊烯、二甲基硫代亚磺酸酯、甲基烯丙基硫代亚磺酸酯等,其中二甲基硫代亚磺酸酯和甲基烯丙基硫代亚磺酸酯产生较强的M+H2O.+信号。未切开的洋葱鳞茎挥发性成分质谱信号较弱,质谱图中主要是一些电晕放电产生的初始离子信号。切开后的洋葱鳞茎挥发性成分质谱信号明显增强,主要是丙烯基次磺酸、丙基烯丙基硫代亚磺酸酯和二丙基硫代亚磺酸酯。大蒜鳞茎挥发性成分主要是二烯丙基硫代亚磺酸酯。切开后的大蒜鳞茎挥发性成分主要是丙烯基次磺酸。实验对韭菜的二甲基硫代亚磺酸酯和甲基烯丙基硫代亚磺酸酯、洋葱的丙烯基次磺酸、大蒜的二烯丙基硫代亚磺酸酯进行了二级串联质谱分析。表面解吸常压化学电离质谱技术无需样品预处理,分析速度快且对样品不造成破坏。     

中国海洋天然产物合成研究新进展

海洋天然产物合成研究是海洋天然有机化学最活跃的研究领域之一。本文综述中国海洋天然产物合成研究的最新进展,包括海洋环肽、西松烷(烯)和西松烷型二萜内酯、喹啉酮衍生物和三丙酮胺以及柳珊瑚酸类似物等。     

海洋天然产物有机化学

本文阐述了海洋天然产物有机化学的迅猛发展、广阔的研究领域以及丰硕的研究成果;论述了海洋和陆地天然产物的差异,以及海洋天然产物的重大医药价值。     

含中氮茚环的二甲川菁的合成

硫代甲酰基中氮茚;碘化二甲基喹啉鎓盐;荧光;含中氮茚环的二甲川菁的合成     

海洋天然产物数据库的设计与建立

对海洋天然产物信息进行了分析，设计并建立了海洋天然产物数据库（Marine Natural Prod-ucts Database,MNPD），该数据库包含海洋天然产物的分子结构及其生物来源、生物活性、生物种类、物理化学参数和参考文献等信息，目前约有11,000条记录。     

Lycogarubin C和Lycogalic Acid A的全合成

Lycogarubin C和Lycogalic acid A是用于研究DNA拓扑异构酶I(Topo I)抑制剂的重要海洋天然产物.我们以叔丁基二甲硅基(TBS)保护的3-丁炔-1醇为起始原料,以二甲基1,2,4,5-四嗪-3,6-二羧酸酯与炔的杂/逆Diels-Alder反应为关键反应,经1,2-二嗪还原,Swern氧化,Fischer吲哚合成等八步反应实现了Lycogarubin C的全合成,再将Lycogarubin C以氢氧化钾处理得到Lycogalic acid A.     

Structure of the lycorinine alkaloid nobilisitine A

The structure 3 recently proposed, on the basis of computed NMR chemical shifts, for the natural product nobilisitine A has been synthesized from its C5-epimer (+)-clividine (4). The spectral data derived from compound 3 match those reported for the natural product.     

合成天然气水合物实验研究

天然气水合物(NGH)是天然气与水在低温高压条件下形成的笼形物,亦称可燃冰.在冻土带和海洋中已发现大量天然气水合物,是清洁燃料的后续天然资源,但开采技术尚不成熟.由于1m~3天然气水合物在常温下可释放约164m~3的天然气和0.8m~3的水,因此合成天然气水合物,可实现天然气的固态运输,更便于在天然气汽车上的储存.本文介绍天然气水合物的基本性质及其人工合成研究取得的进展.     

Stereochemical assignment of the fungal metabolite xestodecalactone A by total synthesis

The first synthesis of the macrocyclic natural product xestodecalactone A, a metabolite of a sponge-derived fungus, is described. By the use of methyl 5-hydroxyhexanoate in its R- or S-configured form, or as its racemate as the precursors, both enantiomers of xestodecalactone A as well as the racemic compound were obtained. Comparison of these synthetic products with the natural product by circular dichroism (CD) spectroscopy and by HPLC on a chiral phase revealed the natural product to have the (R)-configuration.     

Effect of natural clay components on sorption of Cs, Pu and Am by the clay

Sorption of Cs, Pu and Am on natural clay of complex composition was studied to better understand the sorption mechanisms. It was found that cesium sorption to natural clay was affected by its coatings and by the ionic strength of solution. The sorption of Pu and Am on the clay was compared with that on synthetic goethite, hematite and magnetite, representing components of the clay coatings. The sorption was quantitatively interpreted using models assuming ion exchange and/or complex formation on the “layer sites” and “edge sites” of the clay and its coatings. Constants characterizing properties of the sites and sorption equilibria were determined.     

Thermal analysis of mumiyo, the legendary folk remedy from the Himalaya region

Mumiyo is a natural product found mainly in the high mountain ranges of the Himalayas and in some other regions, too. It has been well known as an expensive remedy for a number of diseases for thousands of years. It disappeared completely from the Western medicine and pharmacology, but was frequently used in the former Soviet Union. The present paper concentrates on physical, chemical and microbiological properties of mumiyo, investigated by means of thermal analysis, flow microcalorimetry, capillary electrophoresis, scanning electron microscopy, determination of its natural radioactivity and conventional bioassays with bacteria and fungi. The paper shows that mumiyo is a complex mixture of effective pharmacological substances that acts as a natural bacteriostatic or even bactericidal agent.     

Characterization of kinetics and products of the Baeyer-Villiger oxygenase MtmOIV, the key enzyme of the biosynthetic pathway toward the natural product anticancer drug mithramycin from Streptomyces argillaceus

MtmOIV, the key oxygenase of the mithramycin biosynthetic pathway in Streptomyces argillaceus, was proven to act initially as Baeyer-Villiger monooxygenase, but may also catalyze various follow-up reaction steps. The reaction of the overexpressed pure His6-tagged enzyme with its substrate premithramycin B was studied. Various intermediates and products were isolated and physicochemically characterized, several of them being previously unknown compounds. This is the first example in which a bacterial enzyme was unequivocally proven to act as Baeyer-Villigerase with its natural substrate, that is, in its natural context.     

Electrochemically synthesized polymer of the plant substance embelin (2,5-dihydroxy-3-undecyl-1,4-benzoquinone)

Among the possible new materials for microelectronics, quinones have a number of significant advantages. Similarly, polymers with quinone functionality possess biodegradability. Because natural polymers are promising candidates for functional materials for the future, we have initiated studies on the polymers of natural products. In the present study, a natural quinone (a plant substance) extracted from Embelier libes distributed in the Kerala state of India was electrochemically polymerized and its properties were investigated. The redox activity, electrical conductivity, and biodegradability are discussed.     

天然蛋白质的模拟酶特性研究及应用

本文评述了天然蛋白质作为模拟酶的研究及生物活性物质分析中的应用进展。引用参考文献76篇。     

Mitsunobu Reaction: A Powerful Tool for the Synthesis of Natural Products: A Review

The Mitsunobu reaction plays a vital part in organic chemistry due to its wide synthetic applications. It is considered as a significant reaction for the interconversion of one functional group (alcohol) to another (ester) in the presence of oxidizing agents (azodicarboxylates) and reducing agents (phosphines). It is a renowned stereoselective reaction which inverts the stereochemical configuration of end products. One of the most important applications of the Mitsunobu reaction is its role in the synthesis of natural products. This review article will focus on the contribution of the Mitsunobu reaction towards the total synthesis of natural products, highlighting their biological potential during recent years.     

De novo synthesis of natural products via the asymmetric hydration of polyenes

For the last ten years our group has been working toward the development of an asymmetric hydration approach to polyketide natural products based on the regioselective hydration of di- and tri-enoates. Key to the success of this approach is the recognition that both high regiocontrol and asymmetric induction could be obtained by the use of a Sharpless asymmetric dihydroxylation reaction. Herein we describe the development of the method and its application to natural product total synthesis.