维生素D3合成新工艺的初步设想

维生素D3在医药及临床上有许多重要的应用，其目前都是由7-脱氢胆固醇通过光照反应而得。综述了7-脱氢胆固醇的制备方法，包括两种化学法——溴化／脱溴化氢法和氧化还原消除法。由胆固醇的生物合成全过程，综述采用生物化学法合成7-脱氢胆固醇的研究，提出几种生物法合成7-脱氢胆固醇的构想：①角鲨烯或是羊毛甾醇酶法转化；②麦角固醇生产菌的改造或是采用基因工程的方法；③胆固醇经脱氢酶脱氢转化；④动物细胞培养。     

胆固醇制备7-脱氢胆固醇的研究进展

7-脱氢胆固醇作为制备维生素D_3及其衍生物的关键中间体,主要通过胆固醇烯丙位取代消除反应来合成。综述了7-脱氢胆固醇几种代表性的合成方法,并对合成方法进行了分析总结。     

生物合成7-脱氢胆甾醇酵母底盘的初探

7-脱氢胆甾醇是生产维生素D₃的关键前体,目前利用化学合成和生物转化生产7-脱氢胆甾醇的方法无法适应大规模工业生产的需要,合成生物学的出现为次级代谢物的异源合成提供了新的选择,酿酒酵母和解脂酵母都是适用于工业生产的底盘生物。在酿酒酵母中,麦角固醇合成途径会抑制7-脱氢胆甾醇的合成,通过敲除麦角固醇合成途径上的非必需基因erg5并引入人源的C24还原酶基因dhcr24,可以实现在酿酒酵母中生产7-脱氢胆甾醇,摇瓶发酵产量为2.62 mg·L^-1。解脂酵母中7-脱氢胆甾醇的合成不受麦角固醇的影响,通过将人源的dhcr24基因整合到基因组rDNA位点上,7-脱氢胆甾醇的产量最高达到27.91 mg·L^-1。为寻找适合于异源表达甾醇类次级代谢物的酵母底盘提供了可供借鉴的研究方法,具有一定的指导意义。     

甲酸甲酯合成技术新进展

综述甲醇羰基化法、甲醇脱氢法、合成气直接合成法3种甲酸甲酯合成技术最近几年的开发研究情况。     

我国甲酸甲酯合成技术新进展

综述甲醇羰基化法、甲醇脱氢法、合成气直接合成法三种甲酸甲酯 ( MF)合成技术最近几年的开发研究情况。     

3-羟基丙酸的绿色合成法

3-羟基丙酸是一种重要的化工产品,既可以作为精细化工中间体,也可以合成高聚物。综述采用微生物发酵法和化学转化法制备3-羟基丙酸的研究进展,着重介绍化学转化法,通过比较认为化学转化法更具竞争力,具有广阔的发展前景。     

甲酸甲酯合成技术新进展

综述甲醇羰基化法、甲醇脱氢法、合成气直接合成法３ 种甲酸甲酯（ＭＦ）合成技术最近几年的开发研究情况。     

2-乙基己酸及其铅盐与锡盐的制备

一、前言 2-乙基己酸又称异辛酸,它的盐类是涂料的催干剂,也是聚氨酯树脂与硅橡胶的重要催化剂。关于2-乙基己酸及其盐类的合成方法,作者已发表文献综述。中国科学院化学所用高锰酸钾氧化法合成了2-乙基己酸及其锡盐,南开大学以硝酸氧化法合成了异辛酸并进行了扩大试验,我们采用2-乙基己醇与氢氧化钠为原料,以氧化镉为催化剂的催化脱氢氧化法成功地合     

甲酸甲酯合成技术新进展

综述甲醇羧基化法、甲醇脱氢法、合成气直接合成法3种甲酸甲酯（MF）合成技术最近几年的开发研究情况。     

25-羟基胆固醇的合成方法

正本发明公开了一种25-羟基胆固醇的合成方法。方法如下:以24-脱氢胆固醇衍生物为原料,在有机溶剂中与含羟基试剂在催化作用下进行加成反应,水解反应产物,分离得到25-羟基胆固醇。本发明采用水、甲酸、乙酸、丙酸、丁酸、苯甲酸、对甲基苯甲酸等含羟基试剂代替现有技术中常用的毒性试剂如Cr试剂、Hg试剂和多氟化丙酮。本发明原料易得,对环境影响小。手术及后处理方便。该方法反应     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、环氧树脂、不饱和聚酯树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍。