首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   73篇
  免费   4篇
  国内免费   3篇
化学   77篇
数学   1篇
物理学   2篇
  2021年   2篇
  2020年   5篇
  2019年   3篇
  2018年   2篇
  2017年   4篇
  2016年   5篇
  2015年   4篇
  2014年   10篇
  2013年   21篇
  2012年   4篇
  2011年   7篇
  2010年   6篇
  2009年   3篇
  2006年   1篇
  2001年   2篇
  1992年   1篇
排序方式: 共有80条查询结果,搜索用时 296 毫秒
41.
Using MgO nanoparticle as a recyclable and efficient catalyst, multicomponent reaction of 2-Naphthol, aldehyde derivatives, 4-hydroxycoumarin has led to the synthesis of novel 7-Aryl-6H,7H- benzo[f]chromeno[4,3-b]chromen-6-one derivatives. This study aimed to examine the antimicrobial and antioxidant effects of the synthetic compound in order to reach some benefits, including the synthesis of new derivatives with biological properties, shorter time, high yields, and concordance with green chemistry.  相似文献   
42.
The highly reactive 1∶1 intermediate produced in the reaction of aryl isocyanides and acetylenic esters was trapped by the α‐dicarbonyl compounds to yield γ‐spiroiminolactone derivatives in good yields.  相似文献   
43.
The reactive 1∶1 intermediate generated by the addition of alkyl and aryl isocyanides to dialkyl acetylenedicarboxylate was trapped by 2,7‐dinitrofloren‐9‐one and floren‐9‐one to yield iminolactones in good yields.  相似文献   
44.

Stable crystalline phosphorus ylides were obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and di-tert-butyl acetylendicarboxylate, in the presence of antron, dimedone, indandion, and 3,5-dimethylbarbituric acid. These stable ylides exist in a solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group.  相似文献   
45.
Abstract

For the first time, α-aminophosphonates were obtained by a simple and efficient one-pot method from the reaction between aldehyde, aniline, and triphenyl phosphite in the presence of acetic acid as a catalyst and solvent at room temperature.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

GRAPHICAL ABSTRACT  相似文献   
46.
47.
In this work, a new, green and beneficial nanomagnetic catalyst was easily fabricated using sulfuric acid as an acidic group on Fe3O4 nanoparticles coated with tris (hydroxymethyl) aminomethane (THAM). The synthesized catalyst was characterized by FT-IR, TGA/DTG, XRD, TEM, EDS, VSM, and SEM analyses. Next, its catalytic activity was studied for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives. This catalyst has advantages such as high catalytic activity, non-toxicity, easy separation from the reaction mixture using an external magnet and reuses for several times without significantly reducing in its catalytic activity.  相似文献   
48.
49.
Stable crystalline phosphorus ylides and 1,4-diionic organophosphorus compounds were obtained in good to excellent yields from the 1:1:1 addition reaction between triphenylphosphine, dialkyl acetylenedicarboxylates and β-dicarbonyl or heterocyclic compounds, such as diethyl malonate, acetyl acetone, 1,3-diphenyl propane-1,3-dione, 1,3-dimethylbarbituric acid, meldrum’s acid, 2-benzoxazolinone, benzotirazole, and 2-thiazoline-2-thiol in the presence of sodium dodecyl sulfate as a surfactant in water. Green synthesis, mild conditions, decreasing timescale of reaction, low cost, and easy workup are the main advantages of this method.  相似文献   
50.
α‐Amino phosphonates were obtained in a one‐pot, simple, and efficient method from the reaction between aldehyde, aniline, trialkyl phosphite, and silica sulfuric acid as a catalyst in acetonitrile at room temperature. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:316–318, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20543  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