The reaction of a series of electron-deficient isoindolium-based allenes with sulfhydryl compounds has been studied, leading to the formation of isoindolium-based vinyl sulfides. The vinyl sulfides generated could be readily converted into the corresponding indanones and amines upon heating at 30-70 °C with good yields up to 61 %. The thermal cleavage reaction of vinyl sulfides was further studied for developing temperature-sensitive systems.
View Article and Find Full Text PDFFluorogenic labeling has received considerable attention as a result of the high demand in chemical biology and synthetic biology applications. Herein, we develop a new strategy for fluorescent turn-on ligation targeting alkyne- and quinoline-linked peptides and proteins (λ of 515 nm and up to Φ of 0.20) using the [Cp*RhCl] catalyst.
View Article and Find Full Text PDFFormaldehyde is an abundant contaminant in food and environments causing various diseases. Thus, the development of fast, simple, and selective formaldehyde detection is of great interest. Herein, novel quinolizinium-based fluorescent probes were designed based on a 2-aza-Cope rearrangement reaction and showed high selectivity to formaldehyde by fluorescence emission shift.
View Article and Find Full Text PDFA series of quinolizinium-based fluorescent reagents were prepared by visible light-mediated gold-catalyzed -difunctionalization between quinolinium diazonium salts and electron-deficient alkyne-linked phenylethynyl trimethylsilanes. The electron-deficient alkynyl group of the quinolizinium-based fluorescent reagents underwent nucleophilic addition reaction with the sulfhydryl group on cysteine-containing peptides and proteins. The quinolizinium-based fluorescent reagents were found to function as highly selective reagents for the modification of cysteine-containing peptides and proteins with good to excellent conversions (up to 99%).
View Article and Find Full Text PDFSelective modification of the N-terminus of peptides and proteins is a promising strategy for single site modification methods. Here we report N-terminal selective modification of peptides and proteins by using 2-ethynylbenzaldehydes (2-EBA) for the production of well-defined bioconjugates. After reaction screening with a series of 2-EBA, excellent N-terminal selectivity is achieved by the reaction in slightly acidic phosphate-buffered saline using 2-EBA with electron-donating substituents.
View Article and Find Full Text PDFAlkyne is a useful functionality incorporated in proteins for site-selective bioconjugation reactions. Although effective bioconjugation reactions such as copper(I)-catalyzed and/or copper-free 1,3-dipolar cycloadditions of alkynes and azides are the most common approaches, the development of new alkyne-based bioconjugation reactions is still an ongoing interest in chemical biology. In this work, a new approach has been developed for selective modification of alkyne-linked peptides and proteins through the formation of arylacetylenes by a cross-coupling reaction of 6-membered ring cyclometalated gold(III) (C^N) complexes (HC^N = 2-arylpyridines) with terminal alkynes.
View Article and Find Full Text PDFSingle-site multifunctionalization of glycans is of importance in biological studies considering its crucial role in mediating biological events and human diseases. In this paper, a novel approach for multifunctional labelling of glycans has been developed featuring the use of fluorescence resonance energy transfer-based (FRET-based) probes for fluorescent labelling of glycans through a gold(III)-mediated three-component coupling reaction. Oxidation of glycans into aldehydes followed by the A -coupling reaction with FRET-based probes resulted in the single-site formation of fluorescent propargylamine products.
View Article and Find Full Text PDFModular assembly of cyclometalated gold(III) complexes by choosing appropriate bidentate C,N-donor ligands and ancillary ligands for chemoselective cysteine modification of peptides and proteins via C-S bond-forming reductive elimination has been achieved.
View Article and Find Full Text PDFStable bis-cyclometallated gold(III) complexes were developed as efficient catalysts for organic transformation reactions by using two strategies: (1) construction of distorted square planar gold(III) complexes and (2) dual catalysis by gold(III) complexes and silver salts.
View Article and Find Full Text PDFA site-specific and efficient method for N-terminal modification of peptides using oxone for selective oxidation of N-terminal α-amino groups of peptides to oximes followed by transoximation with O-substituted hydroxylamines has been developed.
View Article and Find Full Text PDFChem Commun (Camb)
April 2012
An efficient gold-catalyzed amide synthesis from aldehydes and amines in aqueous medium under mild reaction conditions has been developed.
View Article and Find Full Text PDFAn efficient approach for modular assembly of multifunctional bioconjugates from oligosaccharides, peptides and proteins with fluorescent probes/affinity tags based on Morita-Baylis-Hillman (MBH) reaction in aqueous medium has been developed.
View Article and Find Full Text PDFAn efficient modular approach for single-site incorporation of two independent functionalities (amines and alkynes) into aldehyde-containing oligosaccharides concurrently by using a one-pot gold-mediated three-component coupling reaction in aqueous medium under mild conditions has been developed.
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