35480-25-2Relevant articles and documents
Synthesis, Characterisation, and Determination of Physical Properties of New Two-Protonic Acid Ionic Liquid and its Catalytic Application in the Esterification
Shahnavaz, Zohreh,Zaharani, Lia,Khaligh, Nader Ghaffari,Mihankhah, Taraneh,Johan, Mohd Rafie
, p. 165 - 172 (2020/10/26)
A new ionic liquid was synthesised, and its chemical structure was elucidated by FT-IR, 1D NMR, 2D NMR, and mass analyses. Some physical properties, thermal behaviour, and thermal stability of this ionic liquid were investigated. The formation of a two-protonic acid salt namely 4,4′-trimethylene-N,N′-dipiperidinium sulfate instead of 4,4′-trimethylene-N,N′-dipiperidinium hydrogensulfate was evidenced by NMR analyses. The catalytic activity of this ionic liquid was demonstrated in the esterification reaction of n-butanol and glacial acetic acid under different conditions. The desired acetate was obtained in 62-88 % yield without using a Dean-Stark apparatus under optimal conditions of 10 mol-% of the ionic liquid, an alcohol to glacial acetic acid mole ratio of 1.3: 1.0, a temperature of 75-100°C, and a reaction time of 4 h. α-Tocopherol (α-TCP), a highly efficient form of vitamin E, was also treated with glacial acetic acid in the presence of the ionic liquid, and O-acetyl-α-tocopherol (Ac-TCP) was obtained in 88.4 % yield. The separation of esters was conducted during workup without the utilisation of high-cost column chromatography. The residue and ionic liquid were used in subsequent runs after the extraction of desired products. The ionic liquid exhibited high catalytic activity even after five runs with no significant change in its chemical structure and catalytic efficiency.
Decarboxylative Acetoxylation of Aliphatic Carboxylic Acids
Senaweera, Sameera,Cartwright, Kaitie C.,Tunge, Jon A.
, p. 12553 - 12561 (2019/10/14)
Organic molecules bearing acetoxy moieties are important functionalities in natural products, drugs, and agricultural chemicals. Synthesis of such molecules via transition metal-catalyzed C-O bond formation can be achieved in the presence of a carefully chosen directing group to alleviate the challenges associated with regioselectivity. An alternative approach is to use ubiquitous carboxylic acids as starting materials and perform a decarboxylative coupling. Herein, we report conditions for a photocatalytic decarboxylative C-O bond formation reaction that provides rapid and facile access to the corresponding acetoxylated products. Mechanistic investigations suggest that the reaction operates via oxidation of the carboxylate followed by rapid decarboxylation and oxidation by Cu(OAc)2
Catalytic Cascade Access to Biaryl-2-Methyl Acetates from Pyruvate O-Arylmethyl Ketoximes via the Palladium-Catalyzed C(sp2)H Bond Arylation and C?O Bond Solvolysis
Shao, Ling-Yan,Xing, Li-Hao,Guo, Ying,Yu, Kun-Kun,Wang, Wei,Liu, Hong-Wei,Liao, Dao-Hua,Ji, Ya-Fei
supporting information, p. 2925 - 2937 (2018/08/17)
A catalytic cascade has been developed for the synthesis of biaryl-2-methyl acetates via a palladium-catalyzed ortho-C(sp2)?H bond arylation of pyruvate O-arylmethyl ketoximes with aryl iodides followed by a solvolysis, in which the pyruvic ketoxime ester as a new auxiliary is employed to direct the C(sp2)?H bond activation. The straightforward treatment of O-arylmethyl hydroxylamines and ethyl pyruvate with aryl iodides also provides the target products in a one-pot fashion. Furthermore, the new palladacycle intermediate is unambiguously confirmed by single-crystal X-ray diffraction analysis. A plausible reaction pathway is proposed for the Pd-catalyzed arylation-acetolysis sequence. (Figure presented.).
