首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 140 毫秒
1.
本文主要研究以1,1-二氯乙烯为主要原料,采用浓盐酸和浓硝酸混酸法,直接合成中间体1,1,1-三氯-2-硝基乙烷。通过正交实验确定了反应的最佳条件。  相似文献   

2.
BINOL类配体是一类重要的具有C2轴、不含手性中心的不对称联芳香化合物。文章将3-硝基-1-萘酸用亚硫酸铁还原成胺,并生成稳定的硫酸盐,之后重氮化,用沸腾的稀硫酸水解成酚,再成酯,最后用三氯化铁在水中偶联合成化合物2,2’-二羟基-1,1'-联二萘-4,4’-二羧酸。并探讨了各反应过程中的影响因素。  相似文献   

3.
以甲酸和氨基硫脲为原料成环制得2-氨基-1,3,4-噻二唑,再经重氮化直接得到2-溴-1,3,4-噻二唑,总收率为31%。  相似文献   

4.
2-巯基-5,7-二甲基-1,2,4-三唑并[1,5—α]嘧啶是合成三唑并嘧啶类衍生物的重要中间体。实验研究了以5-氨基-3-巯基-1,2,4-嘧啶为原料,与乙酰丙酮环合制备2-巯基-5,7-二甲基-1,2,4-三唑并[1,5-α]嘧啶的工艺条件,研究结果表明,在AMZ与乙酰丙酮物质的量比为1:1.1、反应温度为120℃、反应时间为10h时,2-巯基-5,7-二甲基-1,2,4-三唑并[1,5-α]嘧啶的收率达到80%。  相似文献   

5.
以无水氯化铝为催化剂,氯苯和氯乙酰氯为原料,氯化铝与氯乙酰氯的物质的量之比为1.3:1,在45℃条件下反应3-4h,生成2-氯-1-(4-氯苯基)乙酮,产率可达87%;然后再以2-氯-1-(4-氯苯基)乙酮和1,2,4-三唑为原料,用摩尔数为1,2,4-三氮唑3%的四丁基溴化铵为相转移催化剂,45℃下反应4~5h,可得到68%的4’-氯-2-(1H-1,2,4-三唑-1-基)苯乙酮。  相似文献   

6.
以5-氨基-2-巯基-1,3,4-噻二唑为原料,经过胺基酰基化、氯气氧化制得5-乙酰胺基-1,3,4-噻二唑-2-磺酰氯,化合物与N-甲基哌嗪、苯胺反应,合成两个未见报道的目标产物:5-乙酰胺基-1,3,4-噻二唑-2-(N-甲基哌嗪磺酰胺)和5-乙酰胺基-1,3,4-噻二唑-2-(磺酰苯胺).利用IR、H-NMR、LC-MS对目标产物进行表征.  相似文献   

7.
本文主要研究以1,1-二氯乙烯为主要原料,采用浓盐酸和浓硝酸混酸法,直接合成中间体1,1,1-三氯-2-硝基乙烷。通过正交实验确定了反应的最佳条件。  相似文献   

8.
1-甲基-2-硝基亚胺基-5-甲基-六氢化-1,3,5-三嗪的合成   总被引:1,自引:0,他引:1  
在无溶剂、微波辐射下,以N-甲基硝基胍、甲胺水溶液及甲醛为原料合成1-甲基-2-硝基亚胺基-5-甲基-六氢化-1,3,5-三嗪。对产物进行红外光谱、核磁共振分析和熔点测定。用均匀设计方法安排实验,对反应温度、反应时间及反应物用量等影响因素进行考察,回归方程进行优化,经实验验证得反应的最佳条件:反应温度55℃,反应时间50s,N-甲基硝基胍、甲醛、甲胺的摩尔比为1:2.3:2,收率达69.7%。  相似文献   

9.
以取代苯胺为起始原料,经重氮化、叠氮钠取代制得取代叠氮苯,然后在碱性条件下和乙酰乙酸乙酯脱水合环,生成取代三哗酸,。限与二氯亚砜反应得到酰氯,酰氯与碳酸铵研磨得酰胺。该方法反应产物甲.一,产率商,且避免了催化剂的使用,成本较低,反应周期短,效率较高,对环境友好,这为5一甲綦一卜芳摹-1,2,3-三唑-4-甲酸酰胺的合成提供了一种简便有效的方法。  相似文献   

10.
孙国香  王煜华  陆棋 《浙江化工》2004,35(2):13-14,3
以4个N-芳基-5-氨基-1,2,4-三唑-3-磺酰胺为原料,分别与4,4-二甲氧基-2-丁酮在碱性水溶液中环合,制得4个5-甲基-N-芳基-1,2,4-三唑[1,5-a]嘧啶-2-磺酰胺衍生物,并比较了4,4-二甲氧基-2-丁酮的合成路线,所有目标产物的结构均经IR和1HNMR谱验证.  相似文献   

11.
The E,Z, Z,Z, and Z,E geometric isomers of 3,13 octadecadien-1-ol acetate were used singly and in binary combinations to trap sesiids in Wisconsin cherry orchards. The Z,E isomer alone did not capture any sesiids. A synergistic effect, however, of Z,E onSynanthedon pictipes response to its pheromone E,Z was demonstrated for the first time. Strong inhibitory effects of the Z,Z isomer onS. pictipes response to E,Z, and of the E,Z isomer onS. scitula response to Z,Z, were found. As little as 0.5% of Z,Z in E,Z completely inhibited theS. pictipes response. This species' response was also reduced by 85% when Z,Z was evaporated at 4 points, each ca. 6 m from the pheromone trap. Consistencies and discrepancies of the data with relevant experimental results from other geographical areas are briefly discussed.Lepidoptera: Sesiidae (=Aegeriidae), the clearwing moths.Research supported by the College of Agriculture and Life Sciences, University of Wisconsin, Madison, and by the Wisconsin Red Tart Cherry Ind. Market. Order.  相似文献   

12.
Anaphylaxis is a severe, acute, life-threatening multisystem allergic reaction resulting from the release of a plethora of mediators from mast cells culminating in serious respiratory, cardiovascular and mucocutaneous manifestations that can be fatal. Medications, foods, latex, exercise, hormones (progesterone), and clonal mast cell disorders may be responsible. More recently, novel syndromes such as delayed reactions to red meat and hereditary alpha tryptasemia have been described. Anaphylaxis manifests as sudden onset urticaria, pruritus, flushing, erythema, angioedema (lips, tongue, airways, periphery), myocardial dysfunction (hypovolemia, distributive or mixed shock and arrhythmias), rhinitis, wheezing and stridor. Vomiting, diarrhea, scrotal edema, uterine cramps, vaginal bleeding, urinary incontinence, dizziness, seizures, confusion, and syncope may occur. The traditional (or classical) pathway is mediated via T cells, Th2 cytokines (such as IL-4 and 5), B cell production of IgE and subsequent crosslinking of the high affinity IgE receptor (FcεRI) on mast cells and basophils by IgE-antigen complexes, culminating in mast cell and basophil degranulation. Degranulation results in the release of preformed mediators (histamine, heparin, tryptase, chymase, carboxypeptidase, cathepsin G and tumor necrosis factor alpha (TNF-α), and of de novo synthesized ones such as lipid mediators (cysteinyl leukotrienes), platelet activating factor (PAF), cytokines and growth factors such as vascular endothelial growth factor (VEGF). Of these, histamine, tryptase, cathepsin G, TNF-α, LTC4, PAF and VEGF can increase vascular permeability. Recent data suggest that mast cell-derived histamine and PAF can activate nitric oxide production from endothelium and set into motion a signaling cascade that leads to dilatation of blood vessels and dysfunction of the endothelial barrier. The latter, characterized by the opening of adherens junctions, leads to increased capillary permeability and fluid extravasation. These changes contribute to airway edema, hypovolemia, and distributive shock, with potentially fatal consequences. In this review, besides mechanisms (endotypes) underlying IgE-mediated anaphylaxis, we also provide a brief overview of IgG-, complement-, contact system-, cytokine- and mast cell-mediated reactions that can result in phenotypes resembling IgE-mediated anaphylaxis. Such classifications can lead the way to precision medicine approaches to the management of this complex disease.  相似文献   

13.
Rheumatoid arthritis (RA) is a systemic autoimmune disease that primarily affects the joints. Organokines can produce beneficial or harmful effects in this condition. Among RA patients, organokines have been associated with increased inflammation and cartilage degradation due to augmented cytokines and metalloproteinases production, respectively. This study aimed to perform a review to investigate the role of adipokines, osteokines, myokines, and hepatokines on RA progression. PubMed, Embase, Google Scholar, and Cochrane were searched, and 18 studies were selected, comprising more than 17,000 RA patients. Changes in the pattern of organokines secretion were identified, and these could directly or indirectly contribute to aggravating RA, promoting articular alterations, and predicting the disease activity. In addition, organokines have been implicated in higher radiographic damage, immune dysregulation, and angiogenesis. These can also act as RA potent regulators of cells proliferation, differentiation, and apoptosis, controlling osteoclasts, chondrocytes, and fibroblasts as well as immune cells chemotaxis to RA sites. Although much is already known, much more is still unknown, principally about the roles of organokines in the occurrence of RA extra-articular manifestations.  相似文献   

14.
The primary sex pheromone of the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae), was found to include a series of straight-chain hydrocarbon dienes, all with the double bonds in the 9 and 19 positions and all with the (Z, Z) configuration. The major components, of 29, 31, 33, 35, and 37 carbon atoms, were synthesized. In the field and the greenhouse, the synthetic dienes were far above control levels in activity but, at least during the first hours of bioassay, were somewhat less active than the female-derived materials on a weight basis. In the field, a mixture of all five synthetic dienes, in the proportions found in the females, was more attractive than any single one, on a mole basis. In addition, (Z, Z)-9,19 dienes of 28, 30, 32, 34, 36, 38, and 39 carbons have been detected in females in minor amounts. The first five were bioassayed, and each was found to be similar in activity to the 35-carbon component when compared on a weight basis. The synthetic dienes, while active by themselves, were strongly synergized by two, more polar, Florisil fractions derived from females. Experimental design considerations are discussed.  相似文献   

15.
The degree of soil mining by agricultural production in Southern Mali is assessed by calculating nutrient balances: differences between the amount of plant nutrients exported from the cultivated fields, and those added to the fields. Export processes include extraction by crops, losses due to leaching, to erosion, and to volatilization and denitrification. Inputs include applications of fertilizer and manure, restitution of crop residues, nitrogen fixation, atmospheric deposition of nutrients in rain and dust, and enrichment by weathering of soil minerals. Nutrient balances are calculated for N, P, K, Ca, and Mg. Both pessimistic and optimistic estimates are given.The resulting figures indicate, even when the most optimistic estimates are used, large deficits for nitrogen, potassium and magnesium. For the region as a whole, the calculated deficits are -25 kg N/ha,-20 kg K/ha, and -5 kg Mg/ha. Further, acidification is to be expected, in particular in areas where cotton is grown. The deficits are caused by traditional cereal crops, but also by cotton and especially by groundnut. The latter two crops are fertilized, but insufficiently. It is important to note, that the negative figures are not automatic recommendations for application of a specific amount of additional fertilizer. For phosphorus and calcium the balance of the region as a whole appears to be about in equilibrium, but locally large variations may occur.Erosion and denitrification are important causes of nutrient loss, accounting respectively for 17 and 22% of total nitrogen exports. Atmospheric deposition and weathering of minerals in the soil are still important nutrient inputs that contribute as much as nutrients as organic and mineral fertilizer combined. Nutrient depletion is very large in comparison to the amount of fertilizer applied. Drastic options, such as doubling the application of fertilizer or manure, or halving erosion losses, even if feasible, would still not be enough to make up for the calculated deficits.The annual value of withdrawn nutrients, if related to prices of fertilizers, varies between 10,000 and 15,000 FCFA/ha (40-60 US $/ha). Since the estimated average gross margin from farming in this area is 34,000 FCFA/ha (123 US $/ha), soil mining appears to provide an amount equal to 40% of farmers' total income from agricultural activities.  相似文献   

16.
石翛然 《广东化工》2014,(12):191-191
唇膏经微波消解,石墨炉原子吸收光谱法测定样品中铅、锰、铬、镉的含量。在优化的仪器工作条件下,质量浓度分别在32.0、8.0、8.0、8.0 mg/L范围内呈良好的线性关系,检出限分别为4.2、3.5、2.3、2.5μg/L,测得回收率在98%~103%之间,精密度分别为4.1%、3.6%、3.9%、2.7%。  相似文献   

17.
明胶分子量分布测定和表征的研究进展(二)   总被引:2,自引:1,他引:2  
<正> 6.SDS—PAGE(十二烷基硫酸钠-聚丙烯 酰胺凝胶电泳)法 从1959年Raymond和1964年Davis用聚丙烯酰胺凝胶分离人血清蛋白成功后,聚丙烯酰胺凝胶电泳得到了广泛的发展,成为分离、分析蛋白质、核酸类生物  相似文献   

18.
王强 《中国陶瓷》2006,42(1):34-35
匋、陶、窑(窯)上古皆读成舌头音,意义又相通,实际为一个意义上先后产生的几个形体不同的字,先民以陶(匋)既称呼窑灶,又指窑灶出品之物,又指制作陶器;坏(坯)、瓶、瓬、瓿、甂、缶、钵、皿、杯(盃)、盆(瓫)均指窑灶所出之物或后世模仿窑灶出品之物,其字皆由重唇音演变而来,亦为同胞兄弟的同源词。  相似文献   

19.
纳米材料被誉为21世纪的新材料,广泛应用于化工、电子、国防、陶瓷等领域.传统的纳米材料制备方法面临粒径控制较困难、批次间重复性差,存在放大效应等不足.过程强化技术是化学工程学科的研究前沿和热点方向之一,旨在通过在生产过程中采用新工艺、新设备等手段,实现缩减操作单元、减小设备体积、提高生产能力及能量利用效率的目的,是实现...  相似文献   

20.
This feature article presents a state-of-the-art review on versatile shape memory polymer, i.e., polyurethane. It forms an important class of shape memory polymers. Several successful stimuli-responsive effects have been achieved in polyurethane such as electroactive, water-active, pH-sensitive, thermoresponsive, and photoactive effect. Various categories of stimuli-responsive polyurethanes are discussed here. Due to characteristic attributes, such as light weight, low cost, high strength, heat stability, fine shape deformability, and shape memory, polyurethane have found application in aerospace, textile industry, sensors, drug delivery systems, and other biomedical relevance. Future advancement is still needed in this field due to structural and industrial preferences.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号