24666-05-5Relevant academic research and scientific papers
Metal-Free O-Selective Direct Acylation of Amino Alcohols Through Pseudo-Intramolecular Process
Yokoyama, Soichi,Shibauchi, Hiroshi,Asahara, Haruyasu,Nishiwaki, Nagatoshi
supporting information, p. 1125 - 1133 (2019/02/01)
Efficient α-aryl-β-keto ester acylation of amine accompanied by the elimination of ethyl phenylacetate was achieved owing to the pseudo-intramolecular process. The eliminated ethyl phenylacetate could be recycled by conversion into an α-aryl-β-keto ester upon treatment with an acyl chloride in the presence of lithium bis(trimethylsilyl)amide, by which the atom economy considerably increased. Acylation using an α-aryl-β-keto ester is highly sensitive to the bulkiness of the nucleophile, which facilitated the regioselective-acylation of the less hindered amino group in diamine without protecting the other. The transacylation of α-aryl-β-keto ester with N-alkylamino alcohol resulted in chemoselective O-acylation without protecting the amino group because the hydroxy group was attracted to the reaction site of the keto ester by forming an ammonium salt. Transacylation was demonstrated to be a practically useful tool for organic synthesis because this protocol can be conducted under mild conditions with simple manipulations in the absence of any additives such as metal catalyst and base.
Catalytic removal of tert-butyldimethylsilyl (TBS) ether by PVP-I
Ke, Yanxiong,Lu, Guangying,Ren, Jiangmeng,Wang, Di,Zeng, Bu-Bing
, (2019/09/06)
A mild, efficient and rapid protocol the deprotection of alcoholic TBDMS ethers using PVP-1 as catalyst in methanol, the procedure of deprotection of various TBDMS ethers were found to be very convenient, easy work-up, high yielding.
A facile synthesis of 2,4-disubstituted thiazoles using MnO2
Yu, Yan-Bo,Chen, Hong-Liang,Wang, Li-Yi,Chen, Xin-Zheng,Fu, Bin
scheme or table, p. 4858 - 4865 (2010/04/05)
Structurally diverse thiazoles with electron-donating and electron-withdrawing groups were conveniently synthesized through manganese dioxide (MnO2) oxidation of the corresponding thiazolines. The effect of substitution at the 2- and 4-positions was investigated. The desired thiazoles with aryl or vinyl substitutions at the 2- or 4-position can be obtained in good to excellent yields.
Osmylated macroporous resins: Safe, highly efficient and recyclable catalysts for asymmetric aminohydroxylation of olefins
Jo, Cheon Hee,Han, Sien-Ho,Yang, Jung Woon,Roh, Eun Joo,Shin, Ueon-Sang,Song, Choong Eui
, p. 1312 - 1313 (2007/10/03)
Osmylated macroporous resins displayed excellent catalytic performances in the asymmetric aminohydroxylation of olefins and, moreover, these resins were easily recovered and reused without any significant decrease in catalytic efficiencies.
Bromination of Alkenes in Acetonitrile. A Rate and Product Study
Bellucci, Giuseppe,Bianchini, Roberto,Chiappe, Cinzia
, p. 3067 - 3073 (2007/10/02)
The reaction of simple alkenes and aryl alkenes with molecular bromine in damp MeCN occurred with solvent incorporation to give 2-bromo-1-(N-acetylamino)alkanes, 2-methyloxazolines, 2-acetoxyalkylamine hydrobromides, and 2-(N-acetylamino) alcohols.These products arose by the transformation of initially formed 2-bromo-1-(N-acetylamino)alkanes obtained by MeCN attack on bromonium or bromocarbonium ions to give nitrilium tribromide salts.These reacted with water to give 2-bromo-1-(N-acetylamino)alkanes.The kinetic profile of the reaction showed a very fast initial reaction of the alkene and Br2 to yield the nitrilium tribromide, followed by a much slower reaction of Br3(1-) with the alkene.The incorporation of MeCN was Markovnikov and stereospecifically anti.The degree to which incorporation of solvent occurred depended upon the alkene structure and the initial reagent concentrations.A rationalization for the observed chemoselectivity and its dependence on the reaction conditions is offered.
