共查询到20条相似文献,搜索用时 703 毫秒
1.
1-甲基-2,4,5-三硝基咪唑(MTNI)的合成 总被引:1,自引:0,他引:1
以4-硝基咪唑为原料,经硝化、热重排、甲基化等反应合成1-甲基-2,4,5-三硝基咪唑(MTNI),总收率19.4%,纯度>98%,经红外光谱、核磁共振、元素分析等方法表征其结构。研究了反应温度、反应时间等因素对1-甲基-2,4-二硝基咪唑(MDNI)合成及收率的影响,得到了较优的工艺条件:n(2,4-二硝基咪唑)∶n(碘甲烷)=5∶9,反应温度40~45℃,反应时间8h。对硝化反应条件进行了研究,确定了适宜反应时间为1h,反应温度为95℃。 相似文献
2.
以冰乙酸为溶剂,以5-叔丁基-2-羟基苯甲醛和溴素为原料,合成了3-溴-5-叔丁基-2-羟基苯甲醛。考察了溶剂、反应温度、物料比、反应时间等对3-溴-5-叔丁基-2-羟基苯甲醛收率的影响,合成的优化工艺条件为:n(5-叔丁基-2-羟基苯甲醛)∶n(溴素)=1∶1.1,反应温度60℃,反应时间10 h,在此工艺下,收率可达到88.2%,产品经MS、1H NMR确认。 相似文献
3.
4.
5.
以3-甲氧基苯甲醛为原料,经亨利反应、还原硝基和双键、氨基保护、傅-克酰基化、脱甲基、环合、羰基还原等反应,合成目的产物6-2-氨丙基-2,3-二氢苯并呋喃。并对硝基和双键的还原反应、傅-克酰基化和脱甲基反应的工艺条件进行了优化,得出较佳工艺条件:(1) 还原反应:反应温度40 ℃,氢气压力4.0 MPa,Raney-Ni质量为化合物2的质量的8 %,产物收率为78.6 %;(2)合成化合物6的较佳工艺条件:反应温度45 ℃,n(氯乙酰氯):n(化合物4)=1.4:1,反应时间为6 h,产物的收率为68.8 %。 相似文献
6.
7.
利用pGEX-KG载体在大肠杆菌BL21(DE3)中重组表达了L-苏氨酸醛缩酶,以4-硝基苯甲醛、甘氨酸为底物酶法合成了L-4-硝基苯基丝氨酸,考察了反应温度、pH、底物摩尔比和甘氨酸浓度对酶活的影响。最佳转化条件为:反应温度45℃,pH=8.0,甘氨酸与4-硝基苯甲醛底物摩尔比5:1,底物甘氨酸最适浓度为500 mmol/L;0.1 g湿细胞菌体在10 mL反应体系中在最佳反应条件下反应24 h,底物4-硝基苯甲醛转化率为43%,产物L-4-硝基苯基丝氨酸达到9.72g/L,总收率为35%。 相似文献
8.
9.
10.
以3,4-二甲氧基苯甲醛为原料,在二氯亚砜作用下,一步反应合成得到目标产物2-氯-3,4-二甲氧基苯甲醛,其结构经1 HNMR和GC-MS确证。对影响目标产物收率的因素进行了考察,确定的最佳反应条件为:物料n(3,4-二甲氧基苯甲醛)∶n(二氯亚砜)=1∶1.3,反应溶剂为二氯甲烷,反应温度为-30℃,反应时间为16h。在此最佳反应条件下,目标产物的收率为63.4%。 相似文献
11.
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. 相似文献
12.
13.
J. R. Aldrich S. P. Carroll W. R. Lusby M. J. Thompson J. P. Kochansky R. M. Waters 《Journal of chemical ecology》1990,16(1):199-210
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. 相似文献
14.
15.
M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
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. 相似文献
16.
2008~2009年世界塑料工业进展 总被引:4,自引:1,他引:3
中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2010,38(3)
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。 相似文献
17.
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 总被引:15,自引:0,他引:15
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。 相似文献
18.
19.