73018-10-7Relevant academic research and scientific papers
Highly uniform self-assembled monolayers of silver nanospheres for the sensitive and quantitative detection of glutathione by SERS
Chen, Yi,Huang, Feixiang,Jiang, Cailing,Jiang, Li
supporting information, p. 10436 - 10445 (2021/08/09)
The homeostasis and imbalance of glutathione (GSH), an important antioxidant in organisms, are one of the key signals that reflect the health of organisms. In this paper, a novel SERS sensing platform based on Ag film@Si that self-assembled using silver nanospheres was proposed, which was used for the highly sensitive and selective detection of GSH. With the aid of an oil/water/oil three-phase system, the nano-silver film was self-assembled and finally deposited on silicon wafers. The heterobifunctional crosslinking agentN-succinimidyl-3-(2-pyridyldithio)propionate (SPDP), which contains pyridine rings and disulfide bonds, was involved in the exchange reaction between the sulfhydryl groups and disulfide bonds. With the addition of GSH, the breakage of disulfide bonds was promoted, thereby enhancing the SERS signal of SPDP. GSH can be detected sensitively by detecting the changes in the SPDP signal. The detection limit of GSH is 10 nM, and the method is still highly stable when the external environment is serum or other more complex environments.
Integrated preparation method of 2-mercaptopyridine and 2, 2 '-pyridinium sulfide
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Paragraph 0037-0045, (2021/09/15)
The invention discloses an integrated preparation method of 2-mercaptopyridine and 2, 2 '-pyridinium sulfide, which comprises the steps of adding sulfur, sodium sulfide and a composite catalyst into water serving as a solvent, and uniformly stirring under a heating condition until the sulfur, the sodium sulfide and the composite catalyst are all dissolved; then adding 2-halogenated pyridine, and reacting for 20-30 hours at a reflux temperature, wherein the composite catalytic system is prepared by adding a cocatalyst with the same weight as cesium acetate into cesium acetate; after the reaction is finished, cooling the reaction liquid to the room temperature, then conducting extraction to respectively obtain extraction liquid and raffinate reaction liquid, and enabling the extraction liquid and the raffinate reaction liquid to be subjected to aftertreatment respectively to obtain 2, 2 '-pyridinium sulfide and 2-mercaptopyridine. The method can obtain two main products at the same time, and generation of by-products is reduced.
Washington Red (WR) dyes and their imaging applications
Chen, Wei,Xian, Ming
, p. 149 - 163 (2020/06/08)
Near-infrared (NIR) fluorescent dyes with optimum photophysical properties are highly useful for bioimaging in living systems, but such dyes are still rare. Recently, our laboratory developed a unique class of NIR fluorescent dyes with high quantum yields and large Stokes shifts. These dyes, named as Washington Red (WR), were found to be useful scaffolds to develop NIR fluorescent imaging probes upon easy modifications on their phenolic hydroxyl group. In this chapter, we provide a comprehensive summary of this work, including the design and synthesis of WR dyes, their photophysical properties studies, and applications in developing NIR probes to image H2S in cells. The detailed experimental protocols are described.
Promoting Effect of Crystal Water Leading to Catalyst-Free Synthesis of Heteroaryl Thioether from Heteroaryl Chloride, Sodium Thiosulfate Pentahydrate, and Alcohol
Ma, Xiantao,Yu, Jing,Yan, Ran,Yan, Mengli,Xu, Qing
supporting information, p. 11294 - 11300 (2019/09/12)
It is observed the crystal water in sodium thiosulfate pentahydrate (Na2S2O3·5H2O) can promote its multicomponent reaction with heteroaryl chlorides and alcohols, providing a facile, green, and specific synthesis of unsymmetrical heteroaryl thioethers via one-step formation of two C-S bonds under catalyst-, additive-, and solvent-free conditions. Mechanistic studies suggest that the crystal water in Na2S2O3·5H2O is crucial in generating the key thiol intermediates and byproduct NaHSO4, which then catalyzes the dehydrative substitution of alcohols with thiols to afford thioethers.
Copper-Catalyzed Direct Synthesis of Aryl Thiols from Aryl Iodides Using Sodium Sulfide Aided by Catalytic 1,2-Ethanedithiol
Xue, Hongyu,Jing, Bing,Liu, Shasha,Chae, Junghyun,Liu, Yajun
, p. 2272 - 2276 (2017/10/06)
A copper-catalyzed direct and effective synthesis of aryl thiols from aryl iodides using readily available Na 2 S·9H 2 O and 1,2-ethanedithiol was described. A variety of aryl thiols were readily obtained in yields of 76-99%. In this protocol, Na 2 S·9H 2 O was used as ultimate sulfur source, and 1,2-ethanedithiol functioned as an indispensable catalytic reagent.
Hydropersulfides: H-Atom Transfer Agents Par Excellence
Chauvin, Jean-Philippe R.,Griesser, Markus,Pratt, Derek A.
supporting information, p. 6484 - 6493 (2017/09/12)
Hydropersulfides (RSSH) are formed endogenously via the reaction of the gaseous biotransmitter hydrogen sulfide (H2S) and disulfides (RSSR) and/or sulfenic acids (RSOH). RSSH have been investigated for their ability to store H2S in vivo and as a line of defense against oxidative stress, from which it is clear that RSSH are much more reactive to two-electron oxidants than thiols. Herein we describe the results of our investigations into the H-atom transfer chemistry of RSSH, contrasting it with the well-known H-atom transfer chemistry of thiols. In fact, RSSH are excellent H-atom donors to alkyl (k ～ 5 × 108 M-1 s-1), alkoxyl (k ～ 1 × 109 M-1 s-1), peroxyl (k ～ 2 × 106 M-1 s-1), and thiyl (k > 1 × 1010 M-1 s-1) radicals, besting thiols by as little as 1 order and as much as 4 orders of magnitude. The inherently high reactivity of RSSH to H-atom transfer is based largely on thermodynamic factors; the weak RSS-H bond dissociation enthalpy (～70 kcal/mol) and the associated high stability of the perthiyl radical make the foregoing reactions exothermic by 15-34 kcal/mol. Of particular relevance in the context of oxidative stress is the reactivity of RSSH to peroxyl radicals, where favorable thermodynamics are bolstered by a secondary orbital interaction in the transition state of the formal H-atom transfer that drives the inherent reactivity of RSSH to match that of α-tocopherol (α-TOH), nature's premier radical-trapping antioxidant. Significantly, the reactivity of RSSH eclipses that of α-TOH in H-bond-accepting media because of their low H-bond acidity (α2H ～ 0.1). This affords RSSH a unique versatility compared to other highly reactive radical-trapping antioxidants (e.g., phenols, diarylamines, hydroxylamines, sulfenic acids), which tend to have high H-bond acidities. Moreover, the perthiyl radicals that result are highly persistent under autoxidation conditions and undergo very rapid dimerization (k = 5 × 109 M-1 s-1) in lieu of reacting with O2 or autoxidizable substrates.
Efficient Generation of C–S Bonds via a By-Product-Promoted Selective Coupling of Alcohols, Organic Halides, and Thiourea
Ma, Xiantao,Yu, Lei,Su, Chenliang,Yang, Yaqi,Li, Huan,Xu, Qing
supporting information, p. 1649 - 1655 (2017/05/29)
A metal- and base-free three-component coupling of alcohols, heteroaryl halides, and thiourea has been developed for direct and selective synthesis of heteroaryl thioethers. This method can be easily scaled up to the gram scale and extended to dialkyl thioethers, heteroaryl selenides, benzothiazoles, and some antimycobacterially-active thioethers. Mechanistic studies revealed that a by-product-promoted in situ C–O activation of alcohols to more reactive alkyl halides and slow release of the thiol and alkyl halide intermediates are the key to the high selectivity and success of the reaction. (Figure presented.).
Deoxygenation of amine N-oxides using gold nanoparticles supported on carbon nanotubes
Donck, Simon,Gravel, Edmond,Shah, Nimesh,Jawale, Dhanaji V.,Doris, Eric,Namboothiri, Irishi N. N.
, p. 50865 - 50868 (2015/06/25)
Deoxygenation of a variety of aromatic and aliphatic amine N-oxides has been carried out in excellent yield using dimethylphenylsilane as the reducing agent under the catalytic influence of a carbon nanotube-gold nanohybrid at room temperature. Low catalyst loading, good TON and TOF values, and recyclability of the catalyst are some of the salient features of our methodology.
Targeted and armed oncolytic adenovirus via chemoselective modification
Banerjee, Partha S.,Zuniga, Edison S.,Ojima, Iwao,Carrico, Isaac S.
, p. 4985 - 4988 (2011/10/09)
Oncolytic adenoviruses (Ads) are an emerging alternative therapy for cancer; however, clinical trial have not yet demonstrated sufficient efficacy. When oncolytic Ads are used in combination with taxoids a synergistic increase in both cytotoxicity and viral replication is observed. In order to generate a next generation oncolytic adenovirus, virion were physically conjugated to a highly potent taxoid, SB-T-1214, and a folate targeting motif. Conjugation was enabled via the metabolic incorporation of non-canonical monosaccharides (O-GlcNAz) and amino acids (homopropargylglycine), which served as sites for chemoselective modification.
Reduction of amine N-oxides by diboron reagents
Kokatla, Hari Prasad,Thomson, Paul F.,Bae, Suyeal,Doddi, Venkata Ramana,Lakshman, Mahesh K.
experimental part, p. 7842 - 7848 (2011/12/01)
Facile reduction of alkylamino-, anilino-, and pyridyl-N-oxides can be achieved via the use of diboron reagents, predominantly bis- (pinacolato)- and in some cases bis(catecholato)diboron [(pinB)2 and (catB)2, respectively]. Reductions occur upon simply mixing the amine N oxide and the diboron reagent in a suitable solvent, at a suitable temperature. Extremely fast reductions of alkylamino- and anilino-N-oxides occur, whereas pyridyl-N-oxides undergo slower reduction. The reaction is tolerant of a variety of functionalities such as hydroxyl, thiol, and cyano groups, as well as halogens. Notably, a sensitive nucleoside N-oxide has also been reduced efficiently. The different rates with which alkylamino- and pyridyl-N-oxides are reduced has been used to perform stepwise reduction of the N,N-dioxide of (S)-(-)-nicotine. Because it was observed that (pinB)2 was unaffected by the water of hydration in amine oxides, the feasibility of using water as solvent was evaluated. These reactions also proceeded exceptionally well, giving high product yields. In constrast to the reactions with (pinB)2, triethylborane reduced alkylamino-N oxides, but pyridine N-oxide did not undergo efficient reduction even at elevated temperature. Finally, the mechanism of the reductive process by (pinB)2 has been probed by 1H and 11B NMR. (Figure presented) ; 2011 American Chemical Society.
