536-75-4Relevant articles and documents
Scalable, Telescoped Hydrogenolysis-Enzymatic Decarboxylation Process for the Asymmetric Synthesis of (R)-α-Heteroaryl Propionic Acids
Blakemore, Caroline A.,France, Scott P.,Samp, Lacey,Nason, Deane M.,Yang, Eddie,Howard, Roger M.,Coffman, Karen J.,Yang, Qingyi,Smith, Aaron C.,Evrard, Edelweiss,Li, Wei,Dai, Linlin,Yang, Lixia,Chen, Zhiguang,Zhang, Qingli,He, Fangyan,Zhang, Jiesen
supporting information, p. 421 - 426 (2020/11/12)
Enantiopure α-aryl propionic acids are useful building blocks for pharmaceutical research and can be accessed enzymatically using arylmalonate decarboxylases (AMDases) from the corresponding malonic acids. However, the intrinsic instability of malonic acids is a major drawback to this approach in which spontaneous decarboxylation can occur, subsequently eroding enantioselectivity and giving rise to racemic products. This was particularly evident for a panel of N-heterocyclic propionic acids that we wished to access using the approach. Herein, we describe a process to overcome the spontaneous decarboxylation problem in which hydrogenolysis of the corresponding dibenzyl malonates was performed in a biphasic toluene-basic aqueous buffer mixture and telescoped into the subsequent AMDase step. This procedure enabled compounds to be accessed in high enantioselectivities and was successfully demonstrated on 120 g with high yield (76%) and ee (98%).
Chemoselective Hydrogenation of Olefins Using a Nanostructured Nickel Catalyst
Klarner, Mara,Bieger, Sandra,Drechsler, Markus,Kempe, Rhett
supporting information, p. 2157 - 2161 (2021/05/21)
The selective hydrogenation of functionalized olefins is of great importance in the chemical and pharmaceutical industry. Here, we report on a nanostructured nickel catalyst that enables the selective hydrogenation of purely aliphatic and functionalized olefins under mild conditions. The earth-abundant metal catalyst allows the selective hydrogenation of sterically protected olefins and further tolerates functional groups such as carbonyls, esters, ethers and nitriles. The characterization of our catalyst revealed the formation of surface oxidized metallic nickel nanoparticles stabilized by a N-doped carbon layer on the active carbon support.
Preparation method of 4-ethylpyridine
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Paragraph 0060; 0068-0069; 0070; 0078-0079; 0080; 0088-0089, (2019/04/10)
The invention relates to the technical field of organic synthesis, in particular to a preparation method of 4-ethylpyridine. The preparation method of the 4-ethylpyridine comprises the following stepsof: mixing ethyl 4-picolinate with sodium ethoxide, heating to 90 to 110 DEG C, then dropwise adding ethyl acetate, and carrying out claisen condensation reaction, thus obtaining ethyl 3-oxo-3-(4-pyridyl) propionate; mixing the ethyl 3-oxo-3-(4-pyridyl) propionate, dimethyl sulfoxide and water, and carrying out heating treatment, thus obtaining 4-acetylpyridine; cooling after mixing glycol with potassium hydroxide, adding hydrazine hydrate, rising the temperature to 60 to 80 DEG C, then mixing with the 4-acetylpyridine, and carrying out reduction reaction, thus obtaining the 4-ethylpyridine.The 4-ethylpyridine prepared through the preparation method provided by the invention is higher in yield and purity.
