共查询到20条相似文献，搜索用时 78 毫秒
1.
利用3-氯4-氰基5-异噻唑肼与各种芳基异氰酸酯反应,合成了未见文献报道的1-(3-氯4-氰基5-异噻坐氨基)3-芳基脲,产物经元素分析、核磁共振和红外光谱表征。研究表明反应与芳基异氰酸酯上苯环所连的取代基有关,吸电子基有利于反应速度的提高,这与此反应属亲核加成反应机理是一致的。企图利用荒基异硫氰酸酯与3-氯4-氰基5-异噻唑肼反应合成类似结构的芳基硫脲未获成功。 相似文献
2.
林春 《鞍山师范学院学报》1996,(4)
乙基、丙基、丁基、苯基和苄基卤化镁等Grignard试剂与具有三亲电中心的肉桂酰基烯酮环二硫代缩酮类化合物2反应,生成选择性共轭加成产物3,为合成含复杂烃基的a-氧代烯酮环二硫代缩酮提供了一条新的途径.该反应体现了2中的环二硫缩酮基对反应的调控作用. 相似文献
3.
晏志军 《西安文理学院学报》2001,16(3):52-54
用3、4;9、10-二苯并-5、8、16-三氧杂-1、12-二亚胺环十七烷(L1)同过渡金属卤化物作用得到了1-(2′-甲酰基苯基)-4-[2′-(7-氨基-2-亚胺-5-氧杂庚基)苯基]-1、4-二氧杂丁烷(L2)的配合物.用红外分析、元索分析等手段进行了初步表征. 相似文献
4.
杨芝萍 《Journal of Zhangzhou Technical Institute》2005,7(2):1-4
2,6-二氯-4-三氟甲基苯胺经重氮化后与2,3-二氰基丙酸酯反应合成了1-(2,6-二氯-4-三氟甲基苯基)-3-氰基-5-氨基吡唑(1),1与乙酸酐、顺丁烯二酸酐、苯甲酰氯反应,得到1的乙酰胺2a、顺丁烯酰亚胺2b和苯甲酰胺2c.通过元素分析,红外光谱,核磁共振氢谱,核磁共振碳谱,质谱等手段对其结构进行了表征. 相似文献
5.
以无水乙醇作溶剂,采用氨基磺酸作催化剂,脲、乙酰丙酮和对二甲氨基苯甲醛在搅拌加热条件下回流反应3 h,合成了6-甲基-4-(4-二甲氨基)苯基-5-乙酰基-3,4-二氢嘧啶-2(1H)-酮,产率76.6%. 相似文献
6.
朱彬 《黔南民族师范学院学报》2002,22(6):11-13
报道了 8 -喹啉偶氮显色剂 7-(8-喹啉偶氮 ) -8-羟基萘 -1 -氨基 -3 ,6-二磺酸 (7-QAH)的合成。研究了其与Co(Ⅱ )的显色反应。在pH4.7的缓冲体系中 ,试剂与Co(Ⅱ )形成绿色配合物 ,其最大吸收波长位于 648nm ,表观摩尔吸光系数为 3 .6× 1 0 4L·mol-1·cm-1,钴量在 0～ 1 2 μg/ 2 5mL范围内符合比尔定律。 相似文献
7.
报道了α-硫羰基硫代甲酰胺与亚磷酸三甲酯的反应。研究结果表明在乙醚溶剂和室温时生成2，2，4，5－四取代－1，3－二硫杂环戊烯－4的衍生物；在二甲苯溶剂和90－100℃反应时主要生成1，2－二胺基硫代甲酰基－1，2－二芳基乙烯；而在二甲苯溶剂中间流反应时则生成2，5－二胺基－3，4－二芳基噻吩衍生物。 相似文献
8.
对苯二酚和间苯二酚1分别与氯化苄反应生成单醚2,2与9-氯甲基蒽反应生成含有苯环和蒽环的9-(苯基氧甲基)蒽3,3在光照下发生裂解和重排,最后生成蒽环和蒽环间的光致环加成产物bip1anene 4和lepidopterene 5. 相似文献
9.
徐晓舟 《赤峰学院学报(自然科学版)》2013,(11):3-5
以间苯二甲酸为原料,硝化、酯化及还原得到5-氨基间苯二甲酸乙酯,再与8-羟基喹啉反应生成偶氮化合物,利用溴代十六烷取代得到烷基化合物,最后与己二胺发生取代反应合成了5-[8-(十六烷氧基)喹啉偶氮]-1,3-苯二甲酰二己二胺,利用IR、UV-vis和1H NMR对中间体及目标产物结构进行表征. 相似文献
10.
以2-氨基苯腈为起始原料,制备靶向抗肿瘤药物拉帕替尼重要中间体N-(3-氯-4-(3-氟苄氧基)苯基)-6-溴喹唑啉-4-胺。2-氯-4硝基苯酚和间氟苄氯通过Williamson缩合在Zn/NH4Cl还原体系下制备3-氯-4-(3-氟苯甲氧基)苯胺; 2-氨基苯氰通过碘代反应制备2-氨基-5碘苯腈; 2-氨基-5碘苯腈在DMF-DME体系下进行胺-醛缩合得到N'-(4-碘-2-氰基苯基)-N,N-二甲基甲酰胺; N'-(4-碘-2-氰基苯基)-N,N-二甲基甲酰胺与3-氯-4-(3-氟苯甲氧基)苯胺经Dimroth重排得到目标产物;通过熔点测定、LC-MS、1H-NMR确定产物。为提高碘化效率,对3种碘化体系进行评价,其中NH_2I/H_2O_2碘化体系虽反应耗时较长,但产物转化率和选择性较为理想,反应90 h,2-氨基苯腈转化率63%,选择性91. 2%,较为符合绿色化学的要求。 相似文献
11.
罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
12.
邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
13.
Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
14.
Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
18.
Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 相似文献
19.
陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
20.
YANGShiguo 《重庆大学学报(英文版)》2004,3(1):86-88
The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex. 相似文献