The Photophysics of Pyridine-Derivatizedortho-,meta-, andpara-Dibutylamino Cruciforms
摘要:
AbstractThe photophysical properties of a series of para‐substituted donor–acceptor cruciform fluorophores (p1–4) were investigated and compared with their meta and ortho isomers (m1–4 and o1–4). The structural variations were found to have a significant effect on the solvatochromism, fluorescence quantum yields (Φfl), fluorescence lifetimes (τfl), and response upon addition of trifluoroacetic acid. The observed spectral shifts in absorption and emission caused by protonation of the cruciforms make them promising candidates as chemosensors. Additional computational studies provided more insight into the electronic structure of the systems.
Unexpected Rearrangement of 2-Bromoaniline under Biphasic Alkylation Conditions
作者:Scott Barraza、Scott Denmark
DOI:10.1055/s-0036-1590882
日期:2017.12
benzyl bromide under ostensibly basic N-alkylation conditions resulted in migration of bromine from the 2- to the 4-aryl position. Herein we report our studies to elucidate the mechanism of this rearrangement with the objective of suppressing this unexpected outcome. We find that careful choice of reagents is critical, and that this behavior may be extrapolated to alkylation reactions of electron-rich
An efficient N-selective alkylation of primary aromatic amines in molten quaternary ammonium salts, as the solvent, under relatively mild and base-free conditions is presented. On the basis of the Kamlet–Taft parameters and the nucleophilicity of the IL (ionic liquid) anions, the influence of the ionic liquid was evaluated. This protocol was validated on a larger multigram scale and with the syntheses
介绍了在相对温和和无碱的条件下,以熔融季铵盐作为溶剂,伯芳胺的有效 N 选择性烷基化。在 Kamlet-Taft 参数和 IL(离子液体)阴离子的亲核性的基础上,评估了离子液体的影响。该协议在更大的多克规模上进行了验证,并与生物活性杂环(例如,1,4-苯并噻嗪和喹喔啉)和新的高效 MALDI 基质的合成有关。
Chemoselective synthesis of tertiary and secondary amines by reductive amination of aldehydes
A simple and efficient catalyst-free chemoselective reductive amination of primary amines and aldehydes to synthesis of tertiary and secondaryamines with borane complex was developed. Primary amines are converted into tertiary and secondaryamines in one pot reaction under mild condition with good functional group compatibility and It does not require any catalyst to participate in this reaction.