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排序方式: 共有164条查询结果,搜索用时 62 毫秒
1.
Peter?S.?Piispanen Bj?rn?Hedman Torbj?rn?NorinEmail author 《Journal of surfactants and detergents》2002,5(2):165-168
The syntheses of derivatives of dehydroabietic acid suitable for further manipulation into surfactants are presented. The
compounds are produced at very high yields and purity. They contain several different functional groups, e.g., carboxylic
acid, amine, ester, alcohol, and an aromatic group. The functional groups are useful as the linking unit to the hydrophilic
part in synthesizing surfactants. 相似文献
2.
3.
Alicja Wzorek Azusa Sato Józef Drabowicz Vadim A. Soloshonok 《Israel journal of chemistry》2016,56(11-12):977-989
This article is based on a review of literature devoted to the phenomenon of SDE via achiral chromatography since the appearance of the seminal work of Professor Emanuel Gil-Av. The discussed examples of chromatographic studies are related to amides derived from chiral amines and α- and β-amino acids. We discuss the observed SDE magnitude as a function of a compound's structure, and composition of eluent and stationary phases, providing some mechanistic considerations. Particular emphasis is given to the aspect of SDE via achiral chromatography as an emerging unconventional enantiomeric purification technique. 相似文献
4.
Dhananjay S. Rane Man M. Sharma 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1994,59(3):271-277
Some new strategies, such as the use of hydrotropes, surfactants, co-solvent, etc., were applied to the Hofmann reaction of fatty amides to obtain isocyanates, amines and carbamates. Additionally, some industrially important aromatic amines were synthesised. 相似文献
5.
6.
The less polar π‐surface of protein amide groups is exposed in many receptor binding sites, either as part of the backbone or in Gln/Asn side chains. Using quantum chemical calculations and Protein Data Bank (PDB) searches on model systems, we investigate the energetics and geometric preferences for the stacking on amide groups of a large number of heteroarenes that are relevant to medicinal chemistry. From this study, we discern that the stacking energy of an aromatic ligand substituent can be improved by: 1) orienting the fragment dipole vector such that it is aligned in an antiparallel fashion with the dipole of the interacting protein amide group, 2) increasing its dipole moment, and 3) decreasing its π‐electron density. These guidelines should be helpful to more rationally exploit this interaction type in future structure‐based drug design. 相似文献
7.
Maomin Fan Eileen N. Duesler Jerzy F. Janik Robert T. Paine 《Journal of Inorganic and Organometallic Polymers and Materials》2007,17(2):423-437
The transamination reactions between Ti(NMe2)4 and 1,3,4,5,6-pentamethyl-2-aminoborazine, (Me)3N3(Me)2B3(NH2), and diphenylamine (Ph2NH) and between [Zr(NMe2)4]2 and 1,3,4,5,6-pentamethyl-2-aminoborazine, aniline (PhNH2) and diphenylamine have been studied and the molecular product species have been isolated, spectroscopically characterized
and single crystal X-ray structure analyses completed. The results of these studies have been used to interpret the outcome
of reactions of Ti(NMe2)4 and Zr(NMe2)4 with borazinylamine preceramic polymers that, upon pyrolysis, produce TiN/BN, ZrN/BN and ZrH0.6N/BN composite powders.
The transamination reactivity of a two-point poly(borazinylamine) oligomer having terminal –NH2 amino groups with Ti(NMe2)4 and Zr(NMe2)4 has been used to obtain metallated preceramic oligomers that, upon pyrolysis, give TiN/BN and ZrN/ZrH0.6N/BN nanocomposites. Model reactions of 1,3,4,5,6-pentamethyl-2-amino borazine, aniline and Ph2NH2 with Ti(NMe2)4 and Zr(NMe2)4 are also described as models for the formation of the metallated oligomers. Molecular structure determinations for the metal
amides are presented.
We dedicate this paper to Professor Christopher W. Allen in recognition of his distinguished career and his accomplishments
in inorganic ring and polymer chemistry. 相似文献
8.
Sk.Md. Nasiruzzaman Pattubala A.N. Reddy Tae-Jeong Kim 《Inorganic chemistry communications》2009,12(10):964-968
Spontaneous reduction of copper(II) by a bis(ferrocenyl)pyridyl diamide ligand was observed which causes a novel intramolecular N-dealkylation as well as N-oxidation in air. Also observed was the unusual formation of vinyl ferrocene which was confirmed by HPLC and mass spectral techniques. Interestingly, the phenyl analogue of the pyridyl ligand does not show any such transformation. The absorption spectral and electrochemical properties were also reported. 相似文献
9.
Vittorio Pace Wolfgang Holzer Berit Olofsson 《Advanced Synthesis \u0026amp; Catalysis》2014,356(18):3697-3736
The nucleophilic addition of carbon nucleophiles to amides has traditionally been a difficult task, both due to reactivity and selectivity problems. When successful, these processes would represent straightforward routes towards carbonyl‐type or amine compounds, depending on the fate of the generated tetrahedral intermediate. The direct addition of nucleophiles to amides for the preparation of ketones has been studied and applied to the syntheses of several natural products. On the other hand, the addition of nucleophiles to amides to obtain substituted amines represented a major challenge, and only scattered applications on particular substrates have appeared. Initial improvements were based on the activation of amides by introduction of particular substituents, such as in N‐methoxy amides (Weinreb amides) or electron‐withdrawing groups able to increase the carbon nucleophilicity. Although these strategies facilitate the introduction of nucleophiles, chemoselectivity issues arise when additional electrophilic moieties (i.e., carbonyls) are present, thus decreasing the versatility of the methods. In recent years, important advancements towards fully chemoselective methods have been realized. The capture of tetrahedral intermediates with acids generates highly electrophilic iminium species able to undergo chemoselective additions of various nucleophiles, thus accessing substituted amines. Alternatively, the in situ generation of an iminium triflate ion allows highly chemoselective additions of nucleophiles, yielding amines, ketones or ketimines. Also thioamides can be used as precursors of ketones or α‐substituted amines. The success of the above methodologies is further showcased by the application in various syntheses of natural products or biologically active molecules.
10.
Synthesis and isolation of epoxy secondary amidesvia direct amidation ofVernonia galamensis seed oil
Kent A. A. Bryant Chukwuma P. Nwaonicha Mahmoud Hassan Melissa A. Anderson Folahan O. Ayorinde 《Journal of the American Oil Chemists' Society》1993,70(5):457-460
Vernonia galamensis oil, containing naturally epoxidized triglycerides, was reacted withn-butylamine,n-pentylamine andn-hexylamine to afford high yields of epoxidized secondary amides. Three reaction conditions were investigated: (i) reflux
with amines as solvents, (ii) reflux with hexane as the solvent and (iii) room temperature with the amines as solvents. Reactions
with amines as refluxing solvents were completed in 1–5 h, while those with hexane went to completion within 2 to 5 d. Room
temperature reactions were onlyca. 80% complete after several days. Reactivity was increased with higher amine homologs at both reflux and room temperature
reaction conditions. Isolated yields of epoxy-containing amides were about 80% with purity exceeding 96% in all cases. Spectroscopic
characterization of the previously unreported alkyl-vernolamides is provided. 相似文献