93-97-0Relevant articles and documents
The effect of microwave irradiation on carbodiimide-mediated esterifications on solid support
Stadler, Alexander,Kappe, C.Oliver
, p. 3915 - 3920 (2001)
The esterification of a polymer-supported alcohol (PS Wang resin) with benzoic acid was investigated using microwave irradiation. Activation of the carboxylic acid was carried out using diisopropylcarbodiimide, either via the O-acylisourea or symmetrical anhydride protocols. In the microwave-assisted solid-phase coupling using the O-acylisourea method the main product of the reaction was 1-benzoyl-1,3-diisopropylurea, formed by rearrangement of the thermolabile isourea intermediate. On the other hand, significant rate enhancements were observed for the coupling of benzoic anhydride to Wang resin using microwave flash heating in 1-methyl-2-pyrrolidone as solvent. Reaction times were reduced from 2 to 3 days using conventional conditions, to 10 min by microwave dielectric heating.
-
Gerrard,Thrush
, p. 2117,2119 (1959)
-
Multifunctional amphiphilic carbonaceous microcapsules catalyze water/oil biphasic reactions
Tan, Hongyi,Zhang, Peng,Wang, Lei,Yang, Dang,Zhou, Kebin
, p. 11903 - 11905 (2011)
Multifunctional amphiphilic hollow carbonaceous spheres assembled into Pickering emulsions exhibit reversible pH-dependent phase-transfer behavior and can efficiently catalyze water/oil biphasic reactions, facilitating the recycling of the catalysts and separation of the products.
Rh(I)-Catalyzed Direct C6?H Arylation of 2-Pyridones with Aryl Carboxylic Acids
Fan, Qinghua,Pan, Yixiao,Walsh, Patrick J.,Xu, Jianbin,Xu, Lijin,Xu, Xin,Yu, Zexin,Zhao, Haoqiang
supporting information, p. 3995 - 4001 (2021/07/02)
A Rh(I)-catalyzed C6-selective C?H arylation of 2-pyridones with inexpensive, readily available, safe and structurally diverse aryl carboxylic acids with the aid of a pyridine directing group is developed. This decarbonylative arylation protocol features an easy-to-handle catalytic system, and is amenable to diversely substituted 2-pyridones and aryl carboxylic acids. It allows access to a wide range of C6-arylated 2-pyridones, including those that are difficult to prepare using conventional C?H arylation processes. The method tolerates various electron-neutral, electron-rich and electron-deficient functional groups, and affords the products in 41–91% yields. (Figure presented.).
Size-Induced Inversion of Selectivity in the Acylation of 1,2-Diols
Mayr, Stefanie,Zipse, Hendrik
supporting information, p. 18084 - 18092 (2021/12/02)
Relative rates for the Lewis base-catalyzed acylation of aryl-substituted 1,2-diols with anhydrides differing in size have been determined by turnover-limited competition experiments and absolute kinetics measurements. Depending on the structure of the anhydride reagent, the secondary hydroxyl group of the 1,2-diol reacts faster than the primary one. This preference towards the secondary hydroxyl group is boosted in the second acylation step from the monoesters to the diester through size and additional steric effects. In absolute terms the first acylation step is found to be up to 35 times faster than the second one for the primary alcohols due to neighboring group effects.