769-85-7Relevant articles and documents
Red-Emissive Cell-Penetrating Polymer Dots Exhibiting Thermally Activated Delayed Fluorescence for Cellular Imaging
Algar, W. Russ,Christopherson, Cheyenne J.,Hudson, Zachary M.,Paisley, Nathan R.,Xiao, Zhujun
, p. 13342 - 13349 (2021)
Fluorescence imaging in living cells is key to understanding many biological processes, yet autofluorescence from the sample can lower sensitivity and hinder high-resolution imaging. Time-gated measurements using phosphorescent metal complexes can improve imaging, at the cost of potential toxicity from the use of heavy metals. Here, we describe orange/red-emitting polymer dots (Pdots) exhibiting thermally activated delayed fluorescence (TADF) for time-gated imaging. Inspired by the cell invasion mechanism of the HIV TAT protein, the Pdots were formed from block copolymers composed of a hydrophilic guanidine-rich block as a cell-penetrating peptide mimic, and a rigid organic semiconductor block to provide efficient delayed fluorescence. These all-organic polymer nanoparticles were shown to efficiently enter HeLa, CHO, and HepG2 cells within 30 min, with cell viabilities remaining high for Pdot concentrations up to 25 mg mL-1. Pdot quantum yields were as high as 0.17 in aerated water, with the Pdot structure effectively shielding the TADF emitters from quenching by oxygen. Colocalization experiments revealed that the Pdots primarily accumulate outside of lysosomes, minimizing lysosomal degradation. When used for fixed cellular imaging, Pdot-incubated cells showed high signal-to-background ratios compared to control samples with no Pdot exposure. Using time-resolved spectroscopy, the delayed emission of the TADF materials was effectively separated from that of both a biological serum and a secondary fluorescent dye.
New and facile synthesis of aminobicyclo[22.1]heptane-2-carboxylic acids
Kim, Taek-Soo,Seo, Seung-Yong,Shin, Dongyun
supporting information, p. 1243 - 1247 (2015/03/31)
Abstract A facile approach for the stereoselective synthesis of a- and b-2-aminobicyclo[2.2.1]heptane-2-carboxylic acid is described. Substrate-controlled α-carboxylation of norbonene monoester delivered the asymmetric diester intermediate with high diastereoselectivity (up to 35:1). Sequential chemoselective ester cleavage, Curtius rearrangement, and hydrolysis gave the a- and b-isomers of 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid, respectively.
Novel Potassium-Channel Openers: Preparation and Pharmacological Evaluation of Racemic and Optically Active N-(6-Amino-3-pyridyl)-N'-bicycloalkyl-N"-cyanoguanidine Derivatives
Eda, Masahiro,Takemoto, Tadahiro,Ono, Shin-ichiro,Okada, Takehiro,Kosaka, Keigo,et al.
, p. 1983 - 1990 (2007/10/02)
The previous paper reported on the synthesis and pharmacological evaluation of N-(6-amino-3-pyridyl)-N'-bicycloalkyl-N"-cyanoguanidine derivatives, from among which three compounds were selected as potent potassium-channel openers. In the present study, selected compounds were tested for antagonism of potassium-induced contraction of rat aorta, hypotensive activity in normotensive rats, and diuretic activity in spontaneously hypertensive rats. This led to further evaluation of compound (+/-)-10 and selection of (+)-N-(6-amino-3-pyridyl)-N'-hept-2-yl>-N"-cyanoguanidine ((+)-10) (AL0670) for development as an antihypertensive agent. Although AL0670 is regarded as a pinacidil-type K+-channel opener, it showed different pharmacological and conformational profiles from pinacidil.
