Novel Aromatic Polyimides Derived from 5′-t-Butyl-2′-pivaloylimino-3,4,3′′,4′′-m-terphenyltetracarboxylic Dianhydride with Potential Application on Gas Separation Processes
摘要:
A new family of polyimides having two bulky groups in the central ring of a m-terphenyl moiety has been obtained. These polyimides have been synthesized by reaction of four commercial diamines with the electrophilic monomer, 5'-t-butyl-2'-pivaloylimino-3,4,3 '',4 ''-m-terphenyltetracarboxylic acid dianhydride (PTPDA). This monomer has been obtained by a modern C-H-activated arylation method with good yield and purity. The attained polymers showed T, values ranging from 300 to 430 degrees C, thermal stability > 500 degrees C, and excellent solubility in a broad range of solvents, including tetrahydrofuran. Despite having an amide group, uptake of water was low and comparable to that of classical aromatic polyimides. Mechanical properties of polymer Films were good enough to permit the use of these polyimides oil gas separation applications Ell high pressures. Films obtained by casting offered it good balance of permeability and permselectivity with values close to the Robeson upper-bound, in particular for the O-2/N-2 gas pair.
General rhodium-catalyzed oxidative cross-coupling reactions between anilines: synthesis of unsymmetrical 2,2′-diaminobiaryls
作者:Yang Shi、Jiahui Liu、Yudong Yang、Jingsong You
DOI:10.1039/c9cc01733j
日期:——
cross-coupling reactions. Furthermore, this Cp*-free catalytic reaction tolerates a range of functional groups and requires only a low molar ratio of coupling partners. These features expedite the synthesis of unsymmetrical2,2′-diaminobiaryls.
We report the first introduction of 2-bromo-3,3,3-trifluoropropene (BTP) by directed C–H bond functionalization. The developed method gives straightforward access to α-(trifluoromethyl)styrene derivatives without prior prefunctionalization of the substrates. This palladium-catalysed transformation was applied to a broad range of substrates, and the corresponding trifluoromethylated products were obtained
Oxidative C−H/C−H Cross-Coupling Reactions between <i>N</i>
-Acylanilines and Benzamides Enabled by a Cp*-Free RhCl<sub>3</sub>
/TFA Catalytic System
作者:Yang Shi、Luoqiang Zhang、Jingbo Lan、Min Zhang、Fulin Zhou、Wenlong Wei、Jingsong You
DOI:10.1002/anie.201804528
日期:2018.7.16
oxidative C−H/C−H cross‐coupling reaction between an N‐acylaniline and a benzamide has been accomplished for the first time. This process constitutes a step‐economic and highly efficient pathway to 2‐amino‐2′‐carboxybiaryl scaffolds from readily available substrates. A Cp*‐free RhCl3/TFA catalytic system was developed to replace the [Cp*RhCl2]2/AgSbF6 system generally used in oxidative C−H/C−H cross‐coupling
This invention provides compounds of formula (I):
wherein R
1a
, R
1b
, R
1c
, R
1d
, R
2a
, R
2b
, X
1
, X
2
, and G have values as described in the specification, useful as inhibitors of HDAC6. The invention also provides pharmaceutical compositions comprising the compounds of the invention and methods of using the compositions in the treatment of proliferative, inflammatory, infectious, neurological or cardiovascular diseases or disorders.
Transition-metal-free mono- or dinitration of protected anilines
作者:Enrui Dai、Yongrui Dong、Rui Kong、Guangzhang Liu、Ying Dong、Qiong Wu、Deqiang Liang、Yinhai Ma
DOI:10.1080/00397911.2020.1752730
日期:2020.6.2
Abstract An amide-assisted arene nitration is presented, and both mono- and dinitration of protected anilines could be effected by using NaNO2 and NaNO3 as the mono- and bisnitrating agents, respectively. This divergent synthesis is transition-metal- and acid-free, and features a broad substrate scope, low cost, and ortho–para selectivity. Graphical Abstract