Reaction of carbodiimides with α-Br(Cl)-aryl acetic acids produces N,N′-substituted 5-arylhydantoins under very mild conditions and high yields. When the carbodiimides are generated in situ by Staudinger reaction, the process becomes a one-pot, three-component sequential synthesis of libraries of differently substituted 5-arylhydantoins.
Cyclic RGD peptide analogs as antiplatelet antithrombotics
作者:Peter L. Barker、Sherron Bullens、Stuart Bunting、Daniel J. Burdick、Kathryn S. Chan、Tracy Deisher、Charles Eigenbrot、Thomas R. Gadek、Robin Gantzos
DOI:10.1021/jm00089a014
日期:1992.5
(RGD), a common structural element of many integrin ligands, into cyclicpeptides produced a series of peptides of the general structure BrAc-(AA1)-RGD-Cys-OH, which were prepared by solid-phasepeptidesynthesis. Cyclization was accomplished by reaction of the N-terminal bromoacetyl group with the cysteine sulfhydryl at pH 8 at high dilution, resulting in thioether-bridged cyclicpeptides [cyclo-S-Ac-(AA1)-RGD-Cys-OH]
A metal-free and mild approach to 1,3,4-oxadiazol-2(3<i>H</i>)-ones <i>via</i> oxidative C–C bond cleavage using molecular oxygen
作者:Bumhee Lim、Seunggun Park、Jae Hyun Park、Jongsik Gam、Sanghee Kim、Jung Woon Yang、Jeeyeon Lee
DOI:10.1039/c7ob03188b
日期:——
A mild metal-free approach to 1,3,4-oxadiazol-2(3H)-ones via 1,3,4-oxadiazin-5(6H)-ones is described. This novel transformation, promoted by the electron-withdrawing p-substituents on the phenyl group at the α-carbonyl position, features a tandem reaction consisting of oxidative hydroxylation and C–C bond cleavage using molecular oxygen. The method utilizes K2CO3 in CH3CN without any oxidants, transition
Previously we described a series of 5-acylaminobenzophenones with considerable antimalarial activity. Unfortunately, most compounds also displayed high cytotoxicity resulting in low selectivity towards malaria parasites. Through the replacement of the 5-acylamino moiety by simple chlorine and further modifications of the 2-acylamino residue we could obtain inhibitors with improved selectivity towards malaria parasites combined with an acceptable reduction of antimalarial activity. (c) 2011 Elsevier Masson SAS. All rights reserved.