Expedient synthesis of bisabolenol stink bug pheromones via stereodefined cyclohex-2-enones

We recently synthesized all stereoisomers of 1,10-bisaboladien-3-ol and 10,11-epoxy-1-bisabolen-3-ol, including three stink bug pheromones, via a rhodium-catalyzed asymmetric addition of trimethylaluminum to diastereomeric mixtures of cyclohex-2-enones. However, yields of trans isomers were low, and scaling reactions using expensive catalysts were cumbersome. Now we describe a new synthesis of bisabolenol stink bug pheromones via (S)- and (R)-4-((R)-6-methylhept-5-en-2-yl)cyclohex-2-enones prepared by enantioselective Michael additions of methyl vinyl ketone to (S)- and (R)-citronellals and lithium hydroxide monohydrate-catalyzed stereoselective cyclizations of intermediate ketoaldehydes. Addition of methyllithium to these enones provided cis- and trans-1,10-bisaboladien-3-ols, which were separated by chromatography on silica and further converted to 10,11-epoxy-1-bisabolen-3-ols. Thus, we developed more convenient syntheses of pheromones of the rice stink bug, the harlequin bug, and brown marmorated stink bug.     

A Simple and Short Synthesis of Z-6-Heneicosen-11-One and Z-1,6-Heneicosen-11-One,The Sex Pheromones of Douglas-Fir Tussock Moth

Z-6-Heneicosen-11-one (1) and Z-1,6-Heneicosen-11-one (2) are the sex pheromones of the Douglas-Fir Tussock moth, ‘Orgyia Pseudo Sugata’, isolated^1,2 in 1975 and 1978 respectively. In contrast with other lepidopterous pheromones, which are unsaturated C₁₂-C₁₄ primary alcohols or acetates, these were found to be C₂₁ ketones. The Douglas-Fir Tussock moth is a severe defoliator of the Fir forest; consequently, considerable interest attends the synthesis of these two pheromones. A number of syntheses of these two pheromones have been reported3 amongst which is one of our synthesis using N,N-dimethyl acetone 4 hydrazone as key intermediate.     

动物信息素分离检测方法的研究进展

动物信息素由体内腺体分泌,广泛存在于动物的汗液、尿液和唾液中.信息素的分泌与动物的新陈代谢状态密切相关,在不同新陈代谢状态或生理状态下,动物分泌的信息素具有不同的特征,反映了个体非常重要的生物信息.本文简单介绍了动物信息素及其重要性,综述了动物信息素的样本预处理方法和分离分析方法,并对它未来的发展方向进行了展望.     

Design of pheromone releasing nanofibers for plant protection

Plants tend to attract diseases quite similar to human beings. Pesticides tend to be used to control such diseases. An alternative route, at least as far as damages from insects is concerned, envisions the application of pheromones. These cause a disorientation of male insects so that they are no longer able to locate the females, which finally gives rise to suppression of reproduction. The approach considered in this paper is based on the release of pheromones from polymer carriers, in particular, from nanofibers webs as obtained by electrospinning. These may be distributed across the field quite similar to spider webs. The pheromones are required to be incorporated in sufficiently high concentrations in the nanofibers via electrospinning and to be released from the nanofibers for a sufficiently long time expanding over several weeks to months. Polyamide 6 as well as cellulose acetate was used as a polymer carrier in the investigations reported in this contribution. Studies reveal that fluid pheromones can, in fact, be incorporated in the nanofibers to more than 33 wt%. They may undergo a nanoscalar phase separation within the fibers during electrospinning. Furthermore, thermogravimetric studies revealed via in vitro release studies that the pheromones are released from the nanofibers in a nearly linear fashion over a period covering many weeks. Copyright © 2009 John Wiley & Sons, Ltd.     

Characterization of Mass Spectra of Isomeric Dodecenols

The components of some insect sex pheromones are aliphatic long-chain unsaturated acetates, alcohols and aldehydes. For example, some isomers of dodecenols are the main components of sex pheromones of some noctuid moths (Δ7), olethreutine species (Δ8 and Δ9)¹ and so on. Identification of the structure, especially the position of the double bond, is a very important job. GC-MS is a good method to analyze the ng quantity of sample, which is the level of nature sex pheromones. However, the double bond of straight olefinic components has a strong tendency to migrate along the carbon chain prior to fragmentation under electron impact ionization conditions. So the spectra of isomers are very similar and difficult to be identified by the normal mass spectrometry. In this paper, we develop a new method to identify the isomers of dodecenol based on the sum of the intensity ratios of pairs of fragments.     

昆虫信息素缓释技术的研究进展

昆虫信息素是一类由昆虫个体释放于体外来调节或诱发同种其它个体行为与反应的化学物质。 近年来,应用昆虫信息素防治虫害是当前有机农业绿色防控的新技术之一。 与传统农药防治虫害相比,信息素具有高效、无毒、不产生抗药性以及对天敌无害的特点。 此外,昆虫信息素通常易降解且挥发性高。 因此,基于信息素的缓释技术引起了科研工作者的广泛关注,是涵盖化学、材料与农业的新兴交叉学科。 通过某种特定的方法或技术使昆虫信息素缓慢控制释放,既能有效防治虫害,减少农药使用,提升环境生态水平,同时也能促进区域环境化学品总量与农业成本的降低。 本文详细综述了昆虫信息素缓释技术的最新研究进展并对发展前景进行了展望。     

红收获蚁信息素的鉴定

利用色谱－质谱联机技术，在红收获蚁P.barbatus和P.maricopa的毒腺体样品中检测到召引信息素甲基吡嗪（MP）、2，5－二吡嗪（DMP）、3－乙基－2，5－二甲基吡嗪（EDMP）、和三甲基吡嗪（TMP）。利用特征离子色谱技术，在P.barbatus样品中还检测到了含6个碳原子侧链烃基的吡嗪X。根据吡嗪X的质谱图推测其结构为3－仲丁基－2，5－二甲基吡嗪（BDMP）。P.barbatus中DMP，TMP和EDMP的平均相对百分比分别为60.71、26.49、12.80；标准偏差分别为6.91、4.92、5.11;P.maricopa中平均相对百分比和标准偏差分别为47.48、20.35、32.17和15.05、4.05、15.44。     

东北草甸棕壤的零电荷点和界面酸-碱反应特征平衡常数

分别采用电势滴定(Potentiometric titration)法, 质量滴定(Mass titration)法和惰性电解质滴定(Inert electrolyte titration)法测定了荷结构负电荷的东北草甸棕壤的零净电荷点(PZNC), 研究表明荷结构负电荷的土壤依然存在与电解质浓度无关的零净电荷点, 三种方法的实验结果分别为2.9, 5.0和3.3. 相比较而言, 电势滴定法和惰性电解质滴定法的结果相近, 而质量滴定法的结果偏高. 对文献中推算表面质子活性位密度(N_s)的方法进行了改进, 得到东北草甸棕壤样品的N_s为2.5 mmol•g^－1. 根据实验测定的pH_PZNC, N_s和结构电荷密度(σ_st)值直接计算得出东北草甸棕壤样品的界面反应特征平衡常数即1-pK模型中的pK, 2-pK模型中pK_a1^int和pK_a2^int, 分别为3.37, 2.42和4.32, 与文献报道的沉积物和蒙脱土的值相吻合.     

用于昆虫外激素研究的微量顶空收集及热解吸气相色谱进样方法初探

描述了一个结合项空气流收集与无溶剂热解吸气相色谱进样的方法。用填充PorapskQ的微量注射器作为吸附管进行气流收集。将收集物不经溶剂洗脱直接进行热解吸进样。用人工合成的昆虫外激素化合物反-7-十二碳单烯乙酸酯（E-7-DA）及顺-5,反-7-十二碳二烯乙酸酯（Z-5,E-7-DDA）测定了方法的回收率,初步探索了运用于昆虫外激素分析的可行性,并讨论了提高回收率的途径。     

褐煤树脂中游离酸的化学组成与结构特征

对云南潦浒、寻甸、吉林舒兰褐煤树脂中游离酸的化学组成及结构特征进行了对比研究。结果显示,潦浒和寻甸游离树脂酸主要是由云 氢松香酸组成,其它三环二萜酸,如松脂酸、三达松脂酸、氢化松香酸、松香酸以及五环三萜酸均有分布,但含量低。正构烷酸Ｃ１２￣Ｃ２８也存在着分布,且集中在Ｃ１６、Ｃ１８和Ｃ２０上,低碳数支链烷酸也被检出。因此,去氢松香酸是潦浒寻甸游离树脂酸的特征代表物,与此相反,舒半游离树脂酸则主要     

Recent progress in the chemistry and chemical biology of microbial signaling molecules: quorum-sensing pheromones and microbial hormones

Communication among microorganisms is mediated by secretion and detection of microbial signaling molecules such as quorum-sensing pheromones and microbial hormones. The molecules elicit the regulation of important genes necessary for microbial survival and often play important roles in interspecies or even inter-kingdom communication. Recent progress in the study of the signaling molecules has enabled us to eavesdrop on microbial conversations to gain insight on their intercellular communication system. This review summarizes the recent advances in the chemistry and chemical biology of these important microbial signaling molecules: acyl-homoserine lactones (AHLs), AI-2, CAI-1 related α-hydroxy ketones (AHKs), ComX pheromones, diffusible signal factors (DSFs), diffusible extracellular factor (DF), and Phytophthora mating hormones.     

Pheromones, attractants and other chemical cues of aquatic organisms and amphibians

This review covers the subject of pheromones, attractants and other chemical cues of aquatic invertebrates, fishes and amphibians (including salamanders and anurans). Major topics include the sex pheromones of gastropods, salamanders and a giant tree frog, and the conspecific attraction of sperm to ova of some of the organisms and animals described in this review.     

不同煤阶热解半焦的FT-Raman光谱研究

在热天平上采用慢速升温制备了褐煤、高挥发分烟煤和低挥发分烟煤的半焦。采用FT-Raman光谱对半焦进行了分析。半焦800cm^-1至1800cm^-1的Raman光谱可分解为10个谱带,以表征高度无序炭材料中的典型结构。光谱和谱带的强度比都可用来描述半焦的结构特征。在600℃低温热解时,三种煤半焦的结构差异明显。随热解温度升至800℃或900℃,这种差别消失。褐煤中可交换的钠离子影响热解过程中的成焦反应。     

Characterization of victorian soft brown coal wood by microscopic techniques and Curie-Point pyrolysis combined with gas chromatography-mass spectrometry

Pyrolysis combined with gas chromatography-mass spectrometry is used in an attempt to distinguish lignins derived from an angiosperm and a gymnosperm on the basis of their pyrolysis products. The study is extended to examine the pyrolysis products of Australian soft brown coal woods that have undergone varying degrees of gelification during the soft brown coal stage of coalification. Comparison of the lignin and brown coal pyrograms shows that the brown coals may be derived from gymnosperms, which is in agreement with the results of previous microscopic studies. Poorly gelified brown coals are also shown to contain significant amounts of furan-type products which are not present in the gelified soft brown coal woods. No systematic variation was observed in the distribution of methoxy compounds and the macroscopically and microscopically defined degree of gelification. Finally pyrolysis of low rank vitrinites shows a relative lack of substituted phenols in their pyrograms, but a relative increase in concentration of substituted polycyclic aromatics, compared with highly gelified brown coals.     

Synthesis of heterocyclic bioregulators and semiochemicals

Chemistry and biology of oxygen heterocycles as insect pheromones are reviewed referring to exo-brevicomin, disparlure, japonilure and olean. Synthesis of koninginin A, a microbial metabolite, is discussed. Two azetidine alkaloids, penaresidin A and penazetidine A, were synthesized.     

Novel photochromism of differently-linked bis-benzopyrans

The unique photochromic bis-chromene 5 incorporates the structural attributes of both 3 and 4 . UV-vis irradiation of 5 leads to a dark brown colour, which is formed by mixing the purple and red colours observed for the photolysates of 3 and 4 , respectively.     

Recent results in insect pheromone chemistry

Pheromones are substances which are secreted to the outside by an animal, especially an insect, and received by a second individual of the same species, in which they release a specific reaction, for example, a definite behavior or developmental process. The name is derived from the Greek pherein (to bear, transmit) and hormon (impel, excite). Pheromones include, inter alia, sex attractants, warning substances, and “aggregation pheromones”. Many of these substances are effective at very low concentration. The insect pheromones are predominantly derivatives of long-chain, slightly branched hydrocarbons.     

钯催化脱羰反应研究及若干昆虫性信息素的合成

综述了基于钯催化脱羰端烯化反应的若干昆虫性信息素的合成     

昆虫性信息素的固相合成

本综述阐明昆虫性信息素固相合成的最新成就。C.C.Leznoff 开创了昆虫性信息素的固相合成,并合成了一系列信息素。他以二醇为原料,以聚合物三苯甲基氯为保护剂。陈德恒等将保护剂改成聚合物三苯甲基氯硅烷,产率比前人有所提高。陈家威等大大改进了前两人的线路,简化了步骤,只抓住关键的一步进行固相合成,总产率比前人提高得更多。     

Dynamic instability at liquid/vapor interface far from equilibrium

Attempt has been made to elucidate the mechanism of electric potential oscillations at oil-aqueous solution interface involving adsorption at oil-vapor interface on a semi-theoretical basis. The mechanism stipulates adsorption of ammonia, amines and pheromones at the liquid-vapor interface followed by transfer of ions through membrane-aqueous solution interface and subsequent interaction of ammonium (amine) ions and carbocations from pheromones with diffusing halide ions from the bulk. Relationship of the above mechanism with sensing mechanism of smell by olfactory nerves has also been pointed out.