An efficient one-pot protocol for the synthesis of (E)-nitroalkenes by reaction of aldehydes and nitroalkanes in the presence of polymer-bound triphenylphosphine, iodine and imidazole is described. Although the reaction works with similar efficiency with triphenylphosphine and its polymer-bound version, easy removal of the unwanted polymer-bound triphenylphosphine oxide and its recovery as triphenylphosphine provide the edge for practical application of the method. (C) 2013 Elsevier Ltd. All rights reserved.
d-Mannitol-derived novel chiral thioureas: Synthesis and application in asymmetric Henry reactions
作者:Miaoxi Liu、Nan Ji、Li Wang、Peng Liu、Wei He
DOI:10.1016/j.tetlet.2018.01.082
日期:2018.3
Five novel thioureas have been obtained through multi-step reactions from d-Mannitol as starting material and applied as catalysts in the asymmetric Henry reaction. Using catalyst 7a, (1S,2R)-2-nitro-1-phenylpropan-1-ol containing two chiral centers was obtained in high yield and with high selectivity (up to 95% yield, 87% ee, 91:9 dr). This catalyst also retained activity in the presence of water
Antimitotic agents. Alterations at the 2,3-positions of ethyl (5-amino-1,2-dihydropyrido[3,4-b]pyrazin-7-yl)carbamates
作者:Carroll Temple、Gregory A. Rener、Robert N. Comber、William R. Waud
DOI:10.1021/jm00115a005
日期:1991.11
with alpha-amino ketone oximes gave 4-[(2-oxoethyl)amino]pyridine oximes 3, which were reductively cyclized to give a series of ethyl (1,2-dihydro-pyrido[3,4-b]pyrazin-7-yl)carbamates (6). In another approach, alpha-nitro ketones, alpha-oximino ketones, and alpha-nitro alcohols were reduced to give alpha-amino alcohols, which were reacted with 2 to give 4-[(2-hydroxyethyl)amino]pyridines (5). Oxidation
Synthesis of unsaturated silyl nitronates via the silylation of conjugated nitroalkenes
作者:Elizaveta A. Khotyantseva、Andrey A. Tabolin、Roman A. Novikov、Yulia V. Nelyubina、Sema L. Ioffe
DOI:10.1016/j.tetlet.2018.07.011
日期:2018.8
A new method for the synthesis of conjugated silyl nitronates from nitroalkenes is described. The procedure has wide substrate scope and is compatible with in situ generation of the substrates from 2-nitroalcohols or 2-chloro-nitroalkanes. A cascade transformation to give 3,4,5,6-tetrahydropyridine N-oxide derivatives was disclosed.