Aliphatic Carboxylic Acid as Hydrogen-Bond Donor for Converting CO2 and Epoxide into Cyclic Carbonate under Mild Conditions

2021 ◽  
Author(s):  
Zheng Wang ◽  
Yajun Wang ◽  
Qianjie Xie ◽  
Zhiying Fan ◽  
Yehua Shen

The coupling of CO2 and epoxide is promising way to reduce atmospheric carbon by converting it into value-added cyclic carbonate. Pursuing efficient catalysts is highly attractive for the title reaction....

Author(s):  
Haibin Gou ◽  
Xifei Ma ◽  
Qian Su ◽  
Lei Liu ◽  
Ting Ying ◽  
...  

The development of metal-free, high effective and recyclable catalysts plays a pivotal role in transforming CO2 into high value-added products such as cyclic carbonates. In this paper, we have introduced...


Author(s):  
Thomas Gelbrich ◽  
Volker Kahlenberg ◽  
Verena Adamer ◽  
Sven Nerdinger ◽  
Ulrich J. Griesser

The title compound, 2-(3-cyano-4-isobutoxyphenyl)-4-methyl-1,3-thiazole-5-carboxylic acid ethanol monosolvate, C16H16N2O3S·C2H6O, (I), displays intermolecular O—H...O and O—H...N bonds in which the carboxyl group of the febuxostat molecule and the hydroxyl group of the ethanol molecule serve as hydrogen-bond donor sites. These interactions result in a helical hydrogen-bonded chain structure. The title structure is isostructural with a previously reported methanol analogue.


2019 ◽  
Vol 75 (9) ◽  
pp. 1228-1233
Author(s):  
Joanna Wojnarska ◽  
Katarzyna Ostrowska ◽  
Marlena Gryl ◽  
Katarzyna Marta Stadnicka

The carboxylic acid group is an example of a functional group which possess a good hydrogen-bond donor (–OH) and acceptor (C=O). For this reason, carboxylic acids have a tendency to self-assembly by the formation of hydrogen bonds between the donor and acceptor sites. We present here the crystal structure of N-tosyl-L-proline (TPOH) benzene hemisolvate {systematic name: (2S)-1-[(4-methylbenzene)sulfonyl]pyrrolidine-2-carboxylic acid benzene hemisolvate}, C12H15NO4S·0.5C6H6, (I), in which a cyclic R 2 2(8) hydrogen-bonded carboxylic acid dimer with a strong O—(1 \over 2H)...(1 \over 2H)—O hydrogen bond is observed. The compound was characterized by single-crystal X-ray diffraction and NMR spectroscopy, and crystallizes in the space group I2 with half a benzene molecule and one TPOH molecule in the asymmetric unit. The H atom of the carboxyl OH group is disordered over a twofold axis. An analysis of the intermolecular interactions using the noncovalent interaction (NCI) index showed that the TPOH molecules form dimers due to the strong O—(1 \over 2H)...(1 \over 2H)—O hydrogen bond, while the packing of the benzene solvent molecules is governed by weak dispersive interactions. A search of the Cambridge Structural Database revealed that the disordered dimeric motif observed in (I) was found previously only in six crystal structures.


2022 ◽  
Author(s):  
Ke Xiao ◽  
Yongxin Hu ◽  
Yongyong Wan ◽  
XinXin Li ◽  
Qin Nie ◽  
...  

Herein, we report a new glycosylation system for the highly efficient and stereoselective formation of glycosidic bonds using glycosyl N-phenyl trifluoroacetimidate (PTFAI) donors and a charged thiourea hydrogen-bond-donor catalyst. The...


2021 ◽  
Vol 7 (22) ◽  
pp. eabg0396
Author(s):  
Huan Wang ◽  
Yanfei Zhao ◽  
Fengtao Zhang ◽  
Zhengang Ke ◽  
Buxing Han ◽  
...  

Dehydrative cyclization of diols to O-heterocycles is attractive, but acid and/or metal-based catalysts are generally required. Here, we present a hydrogen-bond donor and acceptor cooperative catalysis strategy for the synthesis of O-heterocycles from diols in ionic liquids [ILs; e.g., 1-hydroxyethyl-3-methyl imidazolium trifluoromethanesulfonate ([HO-EtMIm][OTf])] under metal-free, acid-free, and mild conditions. [HO-EtMIm][OTf] is tolerant to a wide diol scope, shows performance even better than H2SO4, and affords a series of O-heterocycles including tetrahydrofurans, tetrahydropyrans, morpholines, dioxanes, and thioxane in high yields. Mechanism investigation indicates that the IL cation and anion serve as hydrogen-bond donor and acceptor, respectively, to activate the C─O and O─H bonds of alcohol via hydrogen bonds, which synergistically catalyze dehydrative cyclization of diols to O-heterocycles. Notably, the products could be spontaneously separated after reaction because of their immiscibility with the IL, and the IL could be recycled. This green strategy has great potential for application in industry.


2021 ◽  
pp. 1-8
Author(s):  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton

The crystal structure of tofacitinib dihydrogen citrate (tofacitinib citrate) has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Tofacitinib dihydrogen citrate crystallizes in space group P212121 (#19) with a = 5.91113(1), b = 12.93131(3), c = 30.43499(7) Å, V = 2326.411(6) Å3, and Z = 4. The crystal structure consists of corrugated layers perpendicular to the c-axis. Within the layers, cation⋯anion and anion⋯anion hydrogen bonds link the fragments into a two-dimensional network parallel to the ab-plane. Between the layers, there are only van der Waals contacts. A terminal carboxylic acid group in the citrate anion forms a strong charge-assisted hydrogen bond to the ionized central carboxylate group. The other carboxylic acid acts as a donor to the carbonyl group of the cation. The citrate hydroxy group forms an intramolecular charge-assisted hydrogen bond to the ionized central carboxylate. Two protonated nitrogen atoms in the cation act as donors to the ionized central carboxylate of the anion. These hydrogen bonds form a ring with the graph set symbol R2,2(8). The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).


2021 ◽  
Author(s):  
Guangyong Liu ◽  
Qian Wang ◽  
Dongxia Yan ◽  
Yaqin Zhang ◽  
Chenlu Wang ◽  
...  

Cleavage of aryl ether (Caryl-O) bonds is crucial for conversion and value-added utilization of lignin and its derivatives, but remains extremely challenging under mild conditions due to strong Caryl-O linkages....


Sign in / Sign up

Export Citation Format

Share Document