全文获取类型
收费全文 | 144篇 |
免费 | 2篇 |
国内免费 | 9篇 |
专业分类
化学 | 150篇 |
晶体学 | 2篇 |
物理学 | 3篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 9篇 |
2019年 | 4篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 2篇 |
2015年 | 6篇 |
2014年 | 10篇 |
2013年 | 10篇 |
2012年 | 6篇 |
2011年 | 10篇 |
2010年 | 4篇 |
2009年 | 12篇 |
2008年 | 11篇 |
2007年 | 8篇 |
2006年 | 7篇 |
2005年 | 10篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1989年 | 1篇 |
排序方式: 共有155条查询结果,搜索用时 15 毫秒
31.
Hydrogen isotope exchange (HIE) is a versatile method for the introduction of deuterium to organic compounds. Herein, regioselective deuteration of sulfonamides is achieved by palladium-Catalyzed HIE reaction. By using amino acid as weakly coordination-directing auxiliary, a variety of sulfonamides are efficiently deuterated at the ortho-position. Placing competing directing groups on the aromatic ring does not affect the site-selectivity. 相似文献
32.
Benigno Macías Isabel García María V. Villa Joaquín Borrs Alfonso Castieiras Francisca Sanz 《无机化学与普通化学杂志》2003,629(2):255-260
Sulfonamides obtained by reaction of 8‐aminoquinoline with benzenesulfonyl, toluene‐4‐sulfonyl and naphthalene‐2‐sulfonyl chlorides have been used to synthetize coordination compounds with ZnII with a ZnL2 composition. Determination of the crystal structures for the resulting complexes by X‐ray diffraction shows a distorted tetrahedral environment for the Zn2+ ions, sulfonamides acting as bidentate ligands through the nitrogen atoms from the sulfonamidate and quinoline groups. FT‐IR, 1H and 13C NMR and mass spectra of these compounds are also discussed. 相似文献
33.
David C. Johnson II 《Tetrahedron letters》2004,45(46):8483-8487
The benzyl groups of β-hydroxy-N-benzyl sulfonamides are labile toward hydrogenolysis-unlike N-benzyl sulfonamides lacking the β-hydroxy moiety. We find that N-acyl-N-benzyl sulfonamides undergo hydrogenolysis under very mild conditions. Based upon these observations, we developed a reversible safety-catch method using tert-butoxycarbonyl moieties to activate N-benzyl sulfonamides toward hydrogenolysis. We also explored the utility of the safety-catch activation method for other nitrogen-based functionality such as N-benzyl carboxamides, imides, and related functionality. 相似文献
34.
Tetsuya Tsujihara Sayaka Endo Tsunayoshi Takehara Takeyuki Suzuki Satoru Tamura Tomikazu Kawano 《Tetrahedron letters》2018,59(25):2450-2453
The synthesis of helically chiral [6]helicene-based sulfonic acid and sulfonamide from enantiomerically pure 1-acetylthio-5,6,9,10-tetrahydro[6]helicene is reported. The first helically chiral disulfonimides were developed as a synthetic application of [6]helicene-based sulfonamide. This new class of organocatalysts was tested in an asymmetric Mukaiyama aldol reaction to obtain up to quantitative yields and enantioselectivities up to 24%. 相似文献
35.
A computational study at the density functional theory level was performed on bioactive and model sulfonamides with the aim of determining the factors affecting the acidity of the sulfonamido group. The effects of introducing different substituents at either the para-aryl or the N1-sulfonamide positions were independently analyzed. A linear correlation was found between sulfonamide acidity and the Hammett constants or charge of the SO2 group of substituents at the para-aryl position. Most N1-substituents were taken from bacteriostatic sulfonamide structures and presented a more complex behavior, possibly due to a conjugation of steric and electronic factors. In the latter situation, sulfonamide acidity and the charge of the SO2 group were not linearly correlated. Interestingly, the acidity of the sulfonamido group was found to be correlated with the reactivity of sulfa drugs towards acylating agents. The implications for the design of suitable sulfonamide prodrugs are discussed. 相似文献
36.
37.
Bromination of alkynes using sodium bromide in the presence of sodium perborate provides a convenient and safe method for generating vicinal dibromoalkenes. 相似文献
38.
39.
Oluwabusola Edetanlen-Elliot 《Tetrahedron letters》2007,48(50):8926-8929
2,4,6-Trichlorophenyl vinyl sulfonate smoothly undergoes intermolecular radical addition under mild initiation conditions mediated by tributyltin hydride and 1-ethylpiperidine hypophosphite (EPHP) to generate a range of functionalised alkyl sulfonamide precursors. This methodology can be used to prepare bifunctional pentafluorophenyl/2,4,6-trichlorophenyl sulfonates in good yields. 相似文献
40.
液相色谱串联质谱法测定猪肉和猪肝中9种磺胺类药物的残留 总被引:1,自引:0,他引:1
建立了高效液相色谱-串联质谱法(HPLC/MS/MS)同时测定猪肉及猪肝中9种磺胺类药物残留的检测方法.样品经10%的Na2SO4溶液和乙腈-氯仿(10:1)提取,乙腈饱和正己烷去脂,使用乙二胺-N-丙基硅烷(PSA)和十八烷基键合相硅胶(ODS C18-N)两种基质分散净化剂净化,采用LC-MS/MS多反应监测(MRM)正离子模式测定,内标法定量.9种磺胺检出限为0.1 ~0.8 μg/kg,在5,10,20μg/kg 3个浓度添加水平,回收率为74.1% ~ 115.8%,相对标准偏差均小于6.2%(n=6). 相似文献