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1.
2-巯基苯并咪唑经溴化反应得到2-溴苯并咪唑.然后与ω-溴代苯乙酮发生亲核取代反应,进一步得到中间体.最后通过Cu(Ⅰ)催化偶联关环得到产物2-苯基噁唑[3,2-a]苯并咪唑.化合物的结构通过1HNMR,13CNMR得到了证实.初步考察了溶剂、碱、配体对Cu(Ⅰ)催化偶联关环得到产物2-苯基噁唑[3,2-a]苯并咪唑反应的影响.  相似文献   

2.
以3-氨基吡啶为原料,通过溴化、亲核取代反应合成中间体6-溴-2-甲氧基-3-氨基吡啶,最后经重氮化反应合成了目标产物6-溴-3-氟-2-甲氧基吡啶,产物结构经过了核磁、液质表征.研究了溴化工艺、溶剂以及甲醇钠对产物收率的影响.结果表明:采用的路线溴化反应后处理无需柱层析或重结晶,收率高;第二步反应优化了溶剂,收率提高到90.1%.  相似文献   

3.
2-巯基苯并咪唑经溴化反应得到2-溴苯并咪唑,然后与ω-溴代苯乙酮发生亲核取代反应进一步得到中间体,最后通过Cu(I)催化偶联关环得到产物2-苯基噁唑[3, 2-a]苯并咪唑。化合物的结构通过1HNMR,13CNMR得到了证实。在本文中,我们也初步考察了溶剂、碱、配体对Cu(I)催化偶联关环得到产物2-苯基噁唑[3, 2-a]苯并咪唑反应的影响。  相似文献   

4.
研究优化了普拉格雷(化合物1)的制备工艺,以4,5,6,7-四氢噻吩并[3,2-C]吡啶盐酸盐为原料通过氨基的三苯基保护、噻吩环的氧化、脱三苯基保护成盐得到2-氧-2,4,5,6,7,7a-六氢噻吩并[3,2-C]吡啶盐酸盐(化合物 2),以环丙基-2-氟苄基酮为原料溴代得到α-环丙基羰基-2-氟苄基溴(化合物 3),化合物2与化合物3在碱性条件下发生亲核取代反应后,不经后处理直接进行乙酰化,一锅法得到普拉格雷,收率60%(以化合物 2 计),高于文献收率(30%),化合物通过质谱(MS-ESI),氢谱(1H NMR)确证.  相似文献   

5.
以D-阿拉伯糖为原料,一锅多步反应得到关键中间体D-阿拉伯糖烯糖(1)。烯糖(1)经亲电加成和酯水解两步反应得到D-2-脱氧核糖(3),总体产率达到64.0%;以烯糖(1)为原料经过亲电加成,酯水解,磺酰化,亲核取代,水解等五步反应合成L-2-脱氧核糖(8),总收率为42.2%,两产物结构均由旋光,NMR和MS确证。  相似文献   

6.
以2-甲基-3-硝基苯酚(I)为原料,先后经过加氢还原、乙酰化、亲核取代、关环及胺解反应,合成了4-苄氧基-1H-吲唑(VI),总的收率为76.3%,所得目标化合物采用FTIR、1H NMR及ESI-MS进行结构表征.研究了4-苄氧基-1-乙酰基-吲唑(Ⅴ)的合成工艺,结果表明,当亚硝酸异戊酯与N-(3-苄氧基-2-甲基苯基)乙酰胺(Ⅳ)的体积比为1.6∶1,反应温度为90℃,反应时间为16 h时,收率可达87.1%.该合成方法具有操作简单、收率高的优势.  相似文献   

7.
以对二氯苯为起始原料,经过乙酰基化、醚化、过氧乙酸氧化、水解得到5-氯-2-(4-氯-苯氧基)-苯酚,改良后的工艺使终产品收率达32.9%,醚化反应改用氢氧化钾代替碳酸钾与对氯苯酚反应制备亲核试剂,均三甲苯代替二甲苯为溶剂,醚化产物收率达到69.2%。氧化反应使用乙酸酐与过氧化氢(w=0.30)反应制备氧化剂,乙酸为溶剂,氧化反应收率达到72.7%。  相似文献   

8.
以醋酸去氢表雄酮为原料,经C17保护,C16溴代,C15和C16间脱溴化氢及C17脱保护4步反应法合成了3β-乙酰氧基雄甾-5,15-二烯-17-酮.探讨了影响缩酮化反应、溴代反应、消除反应及去保护反应的主要因素,测试了各步产物的物理常数,并用高效液相色谱,红外光谱,质谱,氢核磁共振等对产物进行了表征.研究结果表明:缩酮化反应中催化剂对甲苯磺酸与甾体的量比为0.066时比较适宜,过量会产生油状物;溴代反应中,溴化试剂C5H5N·HBr·Br2的性能优于Br2的性能;溴代反应中间体偕二溴代物中,脱溴试剂NaI的性能优于KI的性能,KI的性能优于Zn粉的性能;消除反应中反应速度与叔丁醇钾的用量成正比,溶剂二甲亚砜优于二甲苯;升高温度不利于去保护反应的进行.上述4步反应的收率分别为93.4%,81.8%,88.8%和96.7%,总收率为65. 6%.  相似文献   

9.
利用3-溴苯硫酚和2-溴-1,1-二-甲氧基乙烷为起始原料,经过SN2亲核取代和分子内环化两步反应合成了4-溴苯并[b]噻吩.通过对溶剂、温度、反应时间、多聚磷酸(PPA)用量等影响反应收率的主要因素的考察,得到了合成目标化合物的较佳反应条件.第一步较优条件:选择DMF作为溶剂,反应温度35~45℃;第二步较优条件:100mL氯苯作溶剂情况下,PPA投料量20 g,反应温度110℃.实验结果表明,该反应条件温和,后处理简单,并且目标产物的收率(64.2%)令人满意.产物的结构通过IR,GC-MS和1HNMR进行了确证.  相似文献   

10.
为了拓展菲环化合物的合成方法,利用Suzuki反应、Wittig反应和氮杂环丙烷化反应3步合成了一类新型的联苯取代磺酰基氮丙啶.在三氟甲磺酸催化下,联苯取代磺酰基氨丙啶并未发生分子内亲核开环反应,取而代之的是反应体系中微量的水极容易地与氮丙啶发生开环,继而在酸促进下重排和芳构化,最终得到菲环产物.以2-([1,1′-联苯]-2-yl)-1-对甲苯磺酰基氮丙啶为底物进行反应条件优化,筛选出最佳的反应条件为:三氟甲磺酸(0.2 mmol),溶剂DCE(10 mL),H_2O(0.2 mmol),氮丙啶5(0.2 mmol),室温条件下反应1 h.在此条件下,拓展了这一反应的底物范围,成功合成了9种菲环化合物,产率为33%~65%.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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