Copper‐Catalyzed C−S Coupling of Quaternary Ammonium Salts and Dialkylcarbamodithioic Acid Salts

Abstract

An efficient synthesis of (chiral) alkyl dialkylcarbamodithioates via a CuI-catalyzed CÀ S cross-coupling reaction of (chiral) quaternary ammonium salts and (chiral) dialkylcarbamodithioic acid salts has been developed. CÀ S coupling products were obtained with extremely high ee values and yields, with enantioenriched arylmethyl trimethylammonium triflates affording the inverse absolute configuration.

Multi-stimuli-responsive molecular fluorescent probes for bioapplications

“…2.1 Dual-stimuli-responsive probes activated by pH Due to the metabolism of diseased tissues, the surrounding microenvironments are different from those of normal tissues. [50][51][52] For example, in the tumor microenvironment, the pH value can be distinguished compared with that of normal tissues, 32,53 where the intracellular pH (47.4) is slightly higher than that of normal cells (B7.2) and the extracellular pH (B6.7-7.1) is lower than that of normal cells (B7.4). 54 Moreover, lysosomes, as one of the organelles in cells, have an acidic environment, which can be distinguished from other organelles.…”

“…55,56 Besides, abnormal intracellular pH values are closely related to various diseases. 32,57 In this part, the reported dual-responsive molecular probes that use pH as at least one of the stimuli are summarized. These probes usually use amine derivatives or esters as H + active sites, while another activatable site is designed for the other stimulus.…”

“…29,30 Probes that possess two or more activating biomarkers have been developed as an effective strategy to improve the imaging resolution and sensitivity both in vitro and in vivo. 12,[31][32][33][34] These multi-stimuli-responsive probes have achieved increasing development in recent years, and have been utilized for detecting biomarkers of various diseases, precisely by effectively decreasing the background signal from normal cells and tissues in vivo. [35][36][37][38][39][40][41] Recently, there have been some excellent reviews about molecular probes published from different aspects, such as molecular fluorescent probes based on two-photon excitation, 42 the bioimaging of intracellular enzymatic activities and transformations, 30,44 bioimaging for a specific bioactive species or microenvironment, [44][45][46] and probes for the imaging and therapy of specific diseases.…”

Synthesis of (Enantioenriched) Dibenzyl Thioethers and Disulfides via SN2 Nucleophilic Substitution of Quaternary Ammonium Salts

“…[19] As we can see that all of the above reported methods for formation of CÀ S bond via CÀ N cleavage adopt organosulfur compounds or their salts as the reactants. [20,21] And thus an idea came to us that we may try inorganosulfur compounds, [22,23] such as Na 2 S • 9H 2 O and Na 2 S 2 as nucleophiles to react with benzylic quaternary ammonium salts (Scheme 1, This work). And thus a class of C 2 symmetric (enantioenriched) dibenzylic thioethers and disulfides would be readily synthesized by this new approach.…”

“…As our on-going study on chiral organosulfur chemistry, [18][19][20][21] we wish to report our recent results on synthesis of C 2 symmetric dibenzyl thioethers and disulfides with Na 2 S • 9H 2 O and Na 2 S 2 as nucleophiles via S N 2 nucleophilic substitution. To the best of our knowledge, this transition metal-free reaction of benzylic trimethylammonium salts with inorganic sulfur component sodium sulfide nonahydrate and disodium disulfide for the synthesis of dibenzylic thioethers and disulfides has not been reported yet.…”