2-(对甲基苯基)-3-(对硝基苯基)-5-(2,4-二磺酸苯基)-2H-四唑单钠盐的合成与表征

以苯甲醛-2,4-二磺酸钠为原料,经与对硝基苯肼反应生成苯甲醛-2,4-二磺酸钠对硝基苯腙后与对甲苯胺重氮盐偶合生成甲臜中间体,再用氯气氧化得到标题化合物,其结构经UV、IR、1HNMR确证.     

基于间苯二酚合成2,4-二甲氧基苯甲醛

以间苯二酚为原料通过Vilsmeier醛基化和甲基化两步反应合成2,4-二甲氧基苯甲醛。比较了醛基化和甲基化的先后顺序对目标化合物收率的影响。方法一以三氯氧磷和N,N-二甲基甲酰胺(DMF)先行醛基化制备2,4-二羟基苯甲醛(收率70.4%),再以硫酸二甲酯甲基化制得目标化合物(收率4.5%)。方法二先以硫酸二甲酯或甲基碘甲基化,制备间苯二甲醚(收率分别为79.7%和30.7%),再用三氯氧磷和N-甲基甲酰苯胺(替代DMF)醛基化,以50.7%的收率得到2,4-二甲氧基苯甲醛,先甲基化再酯基化方法简便易控,目标化合物结构经1H NMR确定。     

2,4-二磺酸基苯甲醛含量的测定

本文介绍了一种测定2,4-二磺酸基苯甲醛含量的方法.2,4-二磺酸基苯甲醛与亚硫酸氢钠加成反应生成4-(羟基磺酸基甲基)苯-1,3-二磺酸,再与碳酸氢钠共热释放出亚硫酸氢钠,然后用碘量法测亚硫酸氢钠含量,从而分析2,4-二磺酸基苯甲醛的含量.     

N-2,4-二羟基苯甲醛甘氨酸-水合铜(Ⅱ)的合成

<正> N-2,4-二羟基苯甲醛甘氨酸在分析化学中可作为显色剂和络合剂,N-2,4-二羟基苯甲醛甘氨酸-水合铜在化学工业上可用于一些金属的防腐剂、还可作为抗病毒剂、抗霉菌剂。近来发现具有显著抗癌活性。吴自慎等采用直接合成方法,就是将2,4-二羟基苯甲醛、甘氨酸,铜(Ⅱ)离子直     

间二甲苯羰基化合成2,4-二甲基苯甲醛的反应机理研究

分析了间二甲苯和CO为原料羰基化合成2,4-二甲基苯甲醛的产物组成,指出在无水AlCl3的催化作用下,间二甲苯容易异构化为邻二甲苯和对二甲苯,同时,苯环上甲基的脱落和重排是羰基化产物众多,2,4-二甲基苯甲醛和3,5-二甲基苯甲醛含量最多的根本原因,并据此提出了该反应的机理.     

新型衍生化试剂1-[5-(1-(4-甲基)哌嗪基-2,4-二硝基)苯基]肼的合成及其衍生化性能

以1,5-二氟-2,4-二硝基苯为起始原料合成了标题化合物,利用IR、1HNMR及LC-ESI-MS对标题化合物进行了表征。其在0.025 mol/L HCl溶液中,40℃条件下,与对甲氧基苯甲醛反应20 min,所生成的腙衍生物用反相高效液相色谱法进行分离检测。     

嘧啶衍生物的研究5-苯基偶氮嘧啶化合物的合成

报道了十一种5-苯基偶氮嘧啶化合物的合成。由2,4-二氨基-6-羟基嘧啶、2-甲基-4-氨基-6-羟基嘧啶、胞嘧啶和芳香伯胺的衍生物及对氨基苯甲醛缩氨基硫脲的重氮盐,在醋酸和氢氧化钠溶液中偶氮化而制得。迄今为止,其中十种化合物尚未见文献报道。     

新的5-对羟基苄亚甲基-2-硫代-2,4-咪唑啉二酮苯磺酸酯的合成

以4-羟基苯甲醛和2-硫代乙内酰脲为原料高收率的合成了5-对羟基苄亚甲基-2-硫代-2,4-咪唑啉二酮,再将它与取代苯磺酰氯反应合成了标题化合物,它们的结构经1~HNMR、~(13)CNMR和元素分析确证.     

肉桂酰香豆素-7-酚酯的合成及其荧光性能

以2,4-二羟基苯甲醛为起始原料经过Knoevehgel反应、内酯化反应和酰化反应合成肉桂酰香豆素-7-酚酯。使用HNMR、红外、紫外可见光谱对所合成的催化剂进行表征,并对所合成的化合物进行荧光测试,测试结果表明所合成化合物荧光的λ_（max）位于406 nm。     

木糖醇醛类化合物对聚乙烯结晶结构及性能的影响

分别以木糖醇与对甲基苯甲醛、3,4-二甲基苯甲醛、对乙基苯甲醛为合成原料,利用缩醛反应机理,合成了3种不同的木糖醇醛类化合物,包括1,3-2,4-二亚(对甲基)苄基木糖醇(MDBX)、1,3-2,4-二亚(对乙基)苄基木糖醇(EDBX)、二(3,4-二甲基二苄叉)木糖醇(DMDBX).使用溶液沉淀法制备含有0.3%(质量分数)DMDBX、EDBX、MDBX的聚乙烯(PE)粉末样品.采用X衍射仪、红外光谱仪、偏光显微镜、差示扫描量热仪研究样品的结晶结构和结晶性质.结果表明该类木糖醇醛化合物能够促进PE的异相成核,减小PE球晶尺寸,提高PE结晶度,可以作为PE的结晶成核剂.根据Avrami模型,采用Kissinger方程计算了动力学数据.该类成核剂能提高PE的结晶速率,降低活化能.DMDBX成核结晶效果最明显,EDBX其次,MDBX最小.     

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.     

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.     

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。