Zn(BH4)2还原L-脯氨酸制备L-脯氨醇的合成研究

用Zn(BH4)2还原L-脯氨酸制备了L-脯氨醇。最佳工艺条件是制备Zn(BH4)2的反应时间是20h,还原L-脯氨酸的反应时间是5h,水解温度是四氢呋喃的沸点温度。L-脯氨醇的产率为90%,光学纯度为97%,nD=1·506,αD= 30·1(C2·0,甲苯)。     

L-丙氨酸乙酯还原反应的研究

对L-丙氨酸乙酯的还原方法进行了研究．采用的还原剂有NaBH4,KBH4,KBH4复合还原剂,金属钠,BER树脂,铜铬氧化物．骨架镍等。NaBH4的还原效果优于KBH4。考察了NaBH4还原L-丙氨酸乙酯的影响因素,优化最佳工艺条件为n(NaBH4)：n(L-丙氨酸乙酯)投料比2：1,用水作溶剂,室温下反应4h,收率为84．7％。添加ZnCl2,AlCl3和LiCl能提高KBH4还原活性,其中ZnCl2的效果较好,收率可达60.2％。     

L-苯丙氨醇的制备

以L-苯丙氨酸为原料，经甲酯化后用硼氢化钠作还原剂，在加入氯化锂的条件下还原得到L-苯丙氨醇。还原反应的最佳条件为NaBH4和L-苯丙氨酸甲酯的物质的量比2：1，20℃反应4h，收率达到81％。     

一种改进的由氨基酸酯制备手性氨基醇的新方法

采用NaBH4/CeCl3作为还原体系,在无水甲醇溶剂中,将氨基酸甲酯还原为相应的手性氨基醇。以L-苯丙氨酸甲酯还原制备L-苯丙氨醇的反应为研究对象,考察了催化剂用量、反应温度及时间诸因素对产品收率的影响。结果表明:在n(L-苯丙氨酸甲酯)∶n(CeCl3)=1∶2、反应温度30℃、反应时间2 h的优化条件下,L-苯丙氨醇收率为90.3%。本法有操作简便,收率高等优点,该反应为制备手性氨基醇提供了一种新的有用的合成方法。     

L-天门冬氨酸螯合铜的合成研究及表征

以L-天门冬氨酸为原料,合成了L-广天门冬氨酸螯合铜,运用正交设计实验对影响L-天门冬氨酸螯合铜反应的条件进行研究,获得最佳反应条件：n(L-广天门冬氨酸)：n(氢氧化铜)=2．2：1,反应温度80℃,pH=6．0,反应时间2h,产率可达91．3％。采用有机溶剂沉淀法制备高纯度的L-天门冬氨酸螯合铜,用化学分析和红外光谱分析对其进行研究确认。     

手性拆分剂一水合-L-二苯甲酰酒石酸的合成工艺研究

以L-酒石酸、苯甲酰氯为起始原料,甲苯为溶剂,经过酯化、酐化和水解2步反应得到手性拆分剂一水合-L-苯甲酰酒石酸,并优化了工艺条件。结果表明,在n(L-酒石酸)∶n(苯甲酰氯)=1∶3.1、反应温度为120~125℃、反应时间3.5 h及酸酐水解体系为甲苯/水、n(酸酐)∶n(水)=1∶4、反应温度为100~105℃、水解时间3 h的反应条件下,目标化合物的总收率达84.1%,纯度大于99.5%。该方法反应收率高,后处理简便,污染少,工艺条件易于控制,适合工业生产。     

L-肉碱盐酸盐的制备研究

研究了用氯化L-肉碱腈水解制备L-肉碱盐酸盐的反应工艺,发现在较低反应温度,较长时间的条件下,可以避免脱水副反应,提高产物的产率和纯度。最佳反应条件为：以浓盐酸为水解试剂,反应温度60℃,反应时间8h。在此条件下,L-肉碱盐酸盐的产率为65．8％,光学纯度为99．2％。     

L-青霉胺的制备研究

研究了以D-青霉胺为原料经酰化、拆分、水解制得L-青霉胺的工艺过程。运用正交设计实验对影响乙酰-D、L-青霉胺反应的条件进行研究,以及讨论了水解时间、盐酸浓度对L-青霉胺的产率和光学纯度的影响。得出了最佳的酰化条件:n(D-青霉胺):n(乙酰氯)=1∶2,反应时间为5 h,反应温度为75°C;最佳的水解条件:盐酸浓度为15%,水解时间为2 h;总产率为30.3%,光学纯度为99.2%。     

L-天门冬氨基酸钼螯合物的合成研究

以L-天门冬氨基酸为原料合成制备L-天门冬氨基酸钼螯合物,运用正交设计实验对影响L-天门冬氨基酸螯合钼的条件进行研究,获得最佳反应条件：n(L-天门冬氨基酸)：n(MoO3)=5．5：1,反应温度T=75℃,反应酸度pH=8．0,反应时间t=2h。通过络合滴定,凯氏定氮法,红外光谱对产品进行分析确认。     

由天然左旋多巴合成左旋多巴醇的研究

从广西天然黎豆中提取得到的左旋多巴(Ⅰ)为原料,通过酯化反应得到左旋多巴乙酯(Ⅱ)。采用NaBH4-CeCl3、NaBH4-LiCl、NaBH4-CaCl2作为还原体系,在无水乙醇溶剂中,将左旋多巴乙酯(Ⅱ)还原为左旋多巴醇(Ⅲ)。结果表明,采用NaBH4-CeCl3作为还原体系,有产率高,速度快等优点。该反应中首次采用天然氨基酸合成氨基醇,并采用NaBH4-CeCl3作为还原体系这种新的还原方法。     

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.     

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.     

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。     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。     

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.     

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.     

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.