Desulfurization Of Thiols Research Articles

Desulfurization of Thiols for Nucleophilic Substitution.

Although the desulfurization of thiols is a topic of great importance and has received significant attention, most efforts have focused on the hydrodesulfurization of thiols. In this work, we describe the desulfurization of thiols for nucleophilic substitution. This process occurs rapidly, promoted by the Ph3P/ICH2CH2I system, and can be extended to a wide range of nucleophiles. Notably, free amines can be employed as nucleophiles to synthesize various secondary and tertiary amines. This method tolerates a wide array of functional groups, including hydroxyl groups in amination reactions. Benzyl thiols are particularly reactive and can be completely converted at room temperature within 15 min. Although alkyl thiols show lower reactivity, they can also be converted smoothly at a reaction temperature of 70 °C overnight.

Photo‐induced Desulfurative Processes for Carbon Radical Generation

AbstractThiols constitute an important family among sulfur‐containing compounds, with well‐established applications in various fields ranging from medicine to material science. For instance, thiol residues are good hydrogen donors which reduce radical species in biological or chemical processes. However, even though the S−H bond activation of thiols for providing access to thiyl radicals has been largely studied, desulfurative processes affording carbon‐based radicals by C−S bond activation have been less explored. In recent years, photoredox catalysis has become the prevalent method for the generation of radicals under soft reaction conditions from readily available starting materials under visible light. In this context, recent studies have been devoted to the development of photocatalytic procedures aiming at the desulfurization of thiol derivatives leading to new C−H, C−C or C‐Het bond formation reactions. This review will cover the synthetic methodologies and strategies for photo‐mediated desulfurization of native thiols, thioethers, sulfonium salts and xanthates to access new organic compounds. This emerging field is especially interesting for new transformations of cysteine and peptide derivatives.

Recent progress in photoinduced direct desulfurization of thiols.

The reduction of mercaptans plays an important role in diverse areas such as protein synthesis, polymer science, environmental study, and pharmaceutical chemistry. Despite significant advancements in this area, particularly in light-induced transformations, review articles have rarely been reported on this topic. Thus, this review article emphasizes the direct photoinduced desulfurization and functionalization of thiols to alkanes or coupling products, with a focus on significant advancements made in the last decade. The progress is discussed according to the types of bonds formed from the cleavage of Csp3-SH bonds.

Superfast desulfurization for protein chemical synthesis and modification

Superfast desulfurization for protein chemical synthesis and modification

A Mild, General, Metal‐Free Method for Desulfurization of Thiols and Disulfides Induced by Visible‐Light

Main observation and conclusionA visible‐light‐induced metal‐free desulfurization method for thiols and disulfides has been explored. This radical desulfurization features mild conditions, robustness, and excellent functionality compatibility. It was successfully applied not only to the desulfurization of small molecules, but also to peptides.

Visible-light photoredox-catalyzed desulfurization of thiol- and disulfide-containing amino acids and small peptides.

A scalable protocol for the desulfurization of cysteine by using visible light, the photocatalyst Ir(dF(CF3 )ppy)2 (dtb-bpy)PF6 and triethylphosphite under biphasic reaction conditions has been developed. The loading of the catalyst can be as low as 0.01mol%, which can be efficiently removed during the workup (≤0.3ppm), giving rise to the corresponding desulfurized product in high yields. This method has been applied also to cystine, penicillamine, and reduced and oxidized glutathione. The desulfurization has been found to be pH sensitive, with an optimal pH value of 6.5 and 7.0 for the cysteine derivatives and glutathione, respectively. In addition, during the desulfurization of a decapeptide containing cysteine and methionine, concurrent oxidation of the two sulfur-containing residues to disulfide and sulfoxide has been observed. Therefore, whereas the presented protocol allows a straightforward visible light-mediated desulfurization of simple thiols by using very low catalyst loading and a cost-effective trialkylphosphite as thiyl radical trapping agent, its application to complex substrates needs to be carefully validated. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

Chemoselective modifications for the traceless ligation of thioamide-containing peptides and proteins.

Thioamides are single-atom substitutions of canonical amide bonds, and have been proven to be versatile and minimally perturbing probes in protein folding studies. Previously, our group showed that thioamides can be incorporated into proteins by native chemical ligation (NCL) with Cys as a ligation handle. In this study, we report the expansion of this strategy into non-Cys ligation sites, utilizing radical initiated desulfurization to "erase" the side chain thiol after ligation. The reaction exhibited high chemoselectivity against thioamides, which can be further enhanced with thioacetamide as a sacrificial scavenger. As a proof-of-concept example, we demonstrated the incorporation of a thioamide probe into a 56 amino acid protein, the B1 domain of Protein G (GB1). Finally, we showed that the method can be extended to β-thiol amino acid analogs and selenocysteine.

ChemInform Abstract: Molybdenum‐Mediated Desulfurization of Thiols and Disulfides.

AbstractThe method is applicable to a thiol‐containing steroid derivative.

Molybdenum-Mediated Desulfurization of Thiols and Disulfides

We have successfully achieved the molybdenum hexacarbonyl [Mo(CO)₆] mediated desulfurization of thiols and disulfides. In this reaction, the sulfhydryl (SH) mercapto groups of aryl, benzyl, primary and secondary alkyl thiols, and S–S single bonds of disulfides can be removed. This reaction has high functional group tolerance and is not affected by steric hindrance. The results of the reactions in acetone-<i>d</i> ₆ suggest that the sources of hydrogen in the thiol and disulfide desulfurizations are the hydrogen atom(s) of a sulfhydryl group and acetone (solvent), respectively, and that the desulfurization proceeds via the formation of an organomolybdenum species.

銀/シリカアルミナ上でのチオールの吸着・脱硫機構

銀/シリカアルミナ上でのチオールの吸着・脱硫機構

Fundamental studies of desulfurization processes: reaction of methanethiol on ZnO and Cs/ZnO

The reaction of methanethiol on ZnO and Cs promoted ZnO surfaces has been studied with synchrotron based photoemission and thermal desorption spectroscopy. On ZnO, methanethiol undergoes selective reaction to produce carbon monoxide (37–58%), methane (23–38%), formaldehyde (12–15%), ethane (1–11%), and a mixture of ethylene and acetylene (3–13%). At low temperatures (<100 K), methanethiol reacts to yield thiolate intermediate bound to Zn 2+ cations. The thiolate is stable to 500 K. Above this temperature, C–S bond cleavage occurs to yield methyl intermediate and atomic S. Carbon is removed from the surface as gaseous products above 500 K, and atomic sulfur remains bound to the zinc sites of the surface. Submonolayer amounts of cesium do not have a significant promotional effect on C–S bond cleavage, whereas Cs multilayers are found to significantly lower the activation barrier for C–S bond cleavage. This study illustrates the chemistry associated with the desulfurization of thiols on a catalytically relevant oxide surface.

Photochemical desulfurization of thiols and disulfides

A visible light-induced desulfurization process for thiols and disulfides using triethylphosphite and triethylborane is reported. The reaction can be effected on a range of organic molecules having either primary, secondary or tertiary thiol groups and disulfides without the need of protecting groups. Thus, after treating l-cystine 7, l-cystine dimethylester 8, thioctic amide 9 and glutathione disulfide 10, first with tributylphosphine, later with triethylborane/triethylphosphite under irradiation in a one-pot reaction, the corresponding desulfurized compounds l-Ala, l-Ala, 1-octanamide and γ- l-Glu- l-Ala-Gly, respectively, are prepared in high yields with retention of configuration.

Phosphorus abstraction reactions related to hydrodesulfurization: formation of Cp'2Mo2Co2S3(CO)2(.mu.3-PR) from Cp'2Mo2Co2S3(CO)4 and phosphines

The cluster Cp' 2 Mo 2 Co 2 S 3 (CO) 4 (1) (Cp'=C 5 H 4 Me) abstracts the phosphinidene group R-P at 80 o C from phenylphosphine to form the cubane-like cluster Cp' 2 Mo 2 Co 2 S 3 (CO) 2 (μ 3 -PPh) (4). This is analogous to the desulfurization of thiols and thiophene by 1. Further reaction with the phosphine leads to the phosphine-substituted cubane Cp' 2 Mo 2 Co 2 (CO)(PH 2 Ph)S 3 -(μ 3 -PPh) (5). Reactions of 1 with diphenylphosphine are faster and form the monophosphine adduct as well as the cis and trans diadducts

ChemInform Abstract: Deoxygenation of Alcohols and Desulfurization of Thiols by WCl2(PMePh2)4.

AbstractThe title complex (I) reacts with simple alcohols such as (II) very slowly to give two sets of products in roughly equal amounts, (III) and the alkane (IV) together with (V) and H2.

Deoxygenation of alcohols and desulfurization of thiols by WCl2(PMePh2)4

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDeoxygenation of alcohols and desulfurization of thiols by WCl2(PMePh2)4Soonhee Jang, Lauren M. Atagi, and James M. MayerCite this: J. Am. Chem. Soc. 1990, 112, 17, 6413–6414Publication Date (Print):August 1, 1990Publication History Published online1 May 2002Published inissue 1 August 1990https://doi.org/10.1021/ja00173a048RIGHTS & PERMISSIONSArticle Views380Altmetric-Citations36LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (304 KB) Get e-Alerts Get e-Alerts

Homogeneous Desulfurization of Thiols and Sulfides by Yb[N(SiMe3)2]2.2 THF. Relevance to Heterogeneous and Biological Desulfurizations and the Synthesis of Lanthanide(II) Sulfides

AbstractYb[N(SiMe3)2]2·2THF was found to desulfurize thiols (RSH) and dibenzyl sulfide. With thiols, the extent of desulfurization was a function of the relative stability of the corresponding radical, R·. Radicals were also involved in the desulfurization of dibenzyl sulfide. A unified mechanism involving a series of one‐electron redox steps leading to the generation of organic radical intermediates has been proposed.

Desulfurization of thiols and thioketones by sodium triethylborohydride and iron(II) chloride on alumina

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDesulfurization of thiols and thioketones by sodium triethylborohydride and iron(II) chloride on aluminaHoward Alper, Sharon Ripley, and Trish L. PrinceCite this: J. Org. Chem. 1983, 48, 2, 250–252Publication Date (Print):January 1, 1983Publication History Published online1 May 2002Published inissue 1 January 1983https://doi.org/10.1021/jo00150a020RIGHTS & PERMISSIONSArticle Views461Altmetric-Citations24LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Exceedingly Mild Desulfurization of Thiols by Sodium Triethylhydroborate and Transition Metal Chlorides

Hydrocarbons can be obtained from thiols at room temperature/−78 °C with the new reduction system given below. The procedure is suitable for aromatic, benzylic, and aliphatic thiols; CoCl2 can be used instead of FeCl2. Other chlorides are less effective. equation image