- Modulating Thiol p Ka Promotes Disulfide Formation at Physiological pH: An Elegant Strategy to Design Disulfide Cross-Linked Hyaluronic Acid Hydrogels
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The disulfide bond plays a crucial role in protein biology and has been exploited by scientists to develop antibody-drug conjugates, sensors, and for the immobilization other biomolecules to materials surfaces. In spite of its versatile use, the disulfide chemistry suffers from some inevitable limitations such as the need for basic conditions (pH > 8.5), strong oxidants, and long reaction times. We demonstrate here that thiol-substrates containing electron-withdrawing groups at the β-position influence the deprotonation of the thiol group, which is the key reaction intermediate in the formation of disulfide bonds. Evaluation of reaction kinetics using small molecule substrate such as l-cysteine indicated disulfide formation at a 2.8-fold higher (k1 = 5.04 × 10-4 min-1) reaction rate as compared to the conventional thiol substrate, namely 3-mercaptopropionic acid (k1 = 1.80 × 10-4 min-1) at physiological pH (pH 7.4). Interestingly, the same effect could not be observed when N-acetyl-l-cysteine substrate (k1 = 0.51 × 10-4 min-1) was used. We further grafted such thiol-containing molecules (cysteine, N-acetyl-cysteine, and 3-mercaptopropionic acid) to a biopolymer namely hyaluronic acid (HA) and determined the pKa value of different thiol groups by spectrophotometric analysis. The electron-withdrawing group at the β-position reduced the pKa of the thiol group to 7.0 for HA-cysteine (HA-Cys); 7.4 for N-acetyl cysteine (HA-ActCys); and 8.1 for HA-thiol (HA-SH) derivatives, respectively. These experiments further confirmed that the concentration of thiolate (R-S-) ions could be increased with the presence of electron-withdrawing groups, which could facilitate disulfide cross-linked hydrogel formation at physiological pH. Indeed, HA grafted with cysteine or N-acetyl groups formed hydrogels within 3.5 min or 10 h, respectively, at pH 7.4. After completion of cross-linking reaction, both gels demonstrated a storage modulus G′ ≈ 3300-3500 Pa, which indicated comparable levels of cross-linking. The HA-SH gel, on the other hand, did not form any gel at pH 7.4 even after 24 h. Finally, we demonstrated that the newly prepared hydrogels exhibited excellent hydrolytic stability but can be degraded by cell-directed processes (enzymatic and reductive degradation). We believe our study provides a valuable insight on the factors governing the disulfide formation and our results are useful to develop strategies that would facilitate generation of stable thiol functionalized biomolecules or promote fast thiol oxidation according to the biomedical needs.
- Bermejo-Velasco, Daniel,Azémar, Alice,Oommen, Oommen P.,Hilborn, J?ns,Varghese, Oommen P.
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- Polymeric and dendrimeric pyridoxal enzyme mimics
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Pyridoxal was covalently attached to polyethylenimine polymers, but the resulting materials were found to degrade rapidly. In comparison, the dendrimeric pyridoxals, which possess only one pyridoxal unit at the core of every dendrimer molecule were found to be relatively stable compounds. A total of 12 poly(amidoamine) type dendrimers were synthesized. They range from G1 to G6 with either NMe2 or NHAc termini. The NMe2-terminated pyridoxal dendrimers racemize α-amino acids 50-100 times faster than does simple pyridoxal, while the NHAc-terminated pyridoxal dendrimers racemize α-amino acids only 3-5 times faster than does simple pyridoxal. Both the NMe2- and NHAc-terminated pyridoxal dendrimers decarboxylate 2-amino-2-phenyl-propionic acid 1-3 times faster than simple pyridoxal. The interior polarity in the pyridoxal dendrimers is similar to that of 85:15 water-DMF solution. Furthermore, we successfully incorporated eight lauryl groups to the G5 pyridoxal dendrimer at known positions. The laurylated dendrimer exhibits lower racemization and decarboxylation rates than do the unlaurylated ones, in contrast to the positive rate effects of laurylation in polyethylenimine-pyridoxamines in our previous transamination studies.
- Liu, Lei,Breslow, Ronald
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- Vancomycin disulfide derivatives as antibacterial agents
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A series of lipidated vancomycin analogues 1 bearing disulfide bonds within their lipid chains was designed and synthesized to optimize their ADME profiles while retaining antibacterial potency. These compounds exhibited good activity against resistant organisms and low accumulation in tissues such as kidney and liver.
- Mu, YongQi,Nodwell, Matthew,Pace, John L.,Shaw, Jeng-Pyng,Judice, J. Kevin
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- Method and device for continuously producing thiopropionate series compounds through pipeline type
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The invention discloses a method and a device for continuously producing thiopropionate series compounds through pipeline type, and can simultaneously or separately prepare thiodipropionate compounds. Dithionate type compounds and mercapto ester compounds. The method is simple to operate, low in cost and high in yield, and is suitable for industrial production.
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Paragraph 0085; 0087; 0095; 0097-0099
(2021/11/27)
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- Green Aerobic Oxidation of Thiols to Disulfides by Flavin-Iodine Coupled Organocatalysis
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Coupled catalysis using a riboflavin-derived organocatalyst and molecular iodine successfully promoted the aerobic oxidation of thiols to disulfides under metal-free mild conditions. The activation of molecular oxygen occurred smoothly at room temperature through the transfer of electrons from the iodine catalyst to the biomimetic flavin catalyst, forming the basis for a green oxidative synthesis of disulfides from thiols.
- Iida, Hiroki,Kozako, Ryo,Oka, Marina
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supporting information
p. 1227 - 1230
(2021/06/21)
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- Breakdown of 3-(allylsulfonio)propanoates in bacteria from the Roseobacter group yields garlic oil constituents
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Two analogues of 3-(dimethylsulfonio)propanoate (DMSP), 3-(diallylsulfonio)propanoate (DAllSP), and 3-(allylmethyl-sulfonio)propanoate (AllMSP), were synthesized and fed to marine bacteria from the Roseobacter clade. These bacteria are able to degrade DMSP into dimethyl sulfide and methanethiol. The DMSP analogues were also degraded, resulting in the release of allylated sulfur volatiles known from garlic. For unknown compounds, structural suggestions were made based on their mass spectrometric fragmentation pattern and confirmed by the synthesis of reference compounds. The results of the feeding experiments allowed to conclude on the substrate tolerance of DMSP degrading enzymes in marine bacteria.
- Chhalodia, Anuj Kumar,Dickschat, Jeroen S.
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p. 569 - 580
(2021/03/31)
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- Forging C?S(Se) Bonds by Nickel-catalyzed Decarbonylation of Carboxylic Acid and Cleavage of Aryl Dichalcogenides
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A nickel-catalyzed decarbonylation of carboxylic acids cross-coupling protocol has been developed for the straightforward C?S(Se) bond formation. This reaction is promoted by a commercially-available, user-friendly, inexpensive, air and moisture-stable nickel precatalyst. Various carboxylic acids and a wide range of aryl dichalcogenide substrates were tolerated in this process which afforded products in good to excellent yields. In addition, the present reaction can be conducted on gram scale in good yield.
- Zhou, Jing-Ya,Zhu, Yong-Ming
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p. 2452 - 2461
(2021/06/28)
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- Cyclic telluride reagents with remarkable glutathione peroxidase-like activity for purification-free synthesis of highly pure organodisulfides
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Monoamino cyclic tellurides with a five- or six-membered ring structure and their derivatives were developed as a new class of catalyst for the oxidation of organothiols to organodisulfides in a glutathione peroxidase-like catalytic reaction. Quantitative conversion and high reaction rate were achieved by performing the reaction in an organic-aqueous segmented microflow system. Importantly, the process circumvented product purification, which is a major limitation of current organodisulfide synthetic methods.
- Arai, Kenta,Osaka, Yuui,Haneda, Masahiro,Sato, Yuumi
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p. 3647 - 3655
(2019/07/22)
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- Unsymmetrical Disulfide Synthesis through Photoredox Catalysis
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A facile and eco-friendly visible light-mediated synthesis of symmetrical and unsymmetrical disulfides using tris[2-phenylpyridinato-C2,N]iridium(III) under additive and oxidant free conditions has been disclosed. The developed method is very mild, several functional group tolerant and highly atom economical requiring extremely low amount of catalyst loading (0.5 mol%). (Figure presented.).
- Dethe, Dattatraya H.,Srivastava, Aparna,Dherange, Balu D.,Kumar, B. Vijay
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supporting information
p. 3020 - 3025
(2018/08/23)
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- One-pot synthesis of 4, 5 - dichloro - 2 - isothiazolinone process
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The invention discloses a process for synthesizing 4,5-dichloro-2-methylisothiazolinone by a one-pot method. The process comprises the following steps: mixing methyl acrylate, a methylamine aqueous solution and sulfur to obtain a mixture, introducing hydrogen sulfide gas into the mixture to generate a dimethyl 3,3'-dithiobispropionate crude product; and then, on the basis of the dimethyl 3,3'-dithiobispropionate crude product, introducing methylamine gas to synthesize N, N'-dimethyl-3,3`- dithiodipropionamide, thereby obtaining the product 4,5-dichloro-2-methylisothiazolinone by reacting chlorine gas with the N, N'-dimethyl-3,3- dithiodipropionamide. According to the method provided by the invention, the technical process is simplified, the operation cost is reduced, and wastewater generation amount is greatly reduced; and three steps of carrying out Michael addition reaction, amidation and chlorination can be carried out in the same reaction kettle, so that separating and purifying processes of an intermediate product are reduced, and therefore, the equipment investment is low, and the obtained product is high in purity.
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Paragraph 0036; 0037; 0038
(2017/08/25)
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- SNAr nucleophilic substitution of 1,9-dihalodipyrrins by S- and N- nucleophiles. Synthesis of new dipyrrins bearing pendant substituents
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5-Aryl-1,9-dichlorodipyrrins react with a series of S- and N- nucleophiles (both alkyl- and aryl- ones). Reagents with mercapto group yield product of double nucleophilic substitution of 5-pheny-1,9-dichlorodipyrrin, i.e. the respective 1,9-bis(alkyl-of arylthio)dipyrrin. On the contrary, 5-(4-nitrophenyl)-1,9-dichlorodipyrrin causes disulfides formation from the S-aliphatic substrates, whereas nucleophilic substitution remains the main path of the reaction for S-aryl ones. The reaction of N-Alkyl nucleophiles proceeds as mono-substitution. UV-Vis spectra feature a batochromic shift for bis-S-substituted products and a hypsochromic shift for mono-N-substituted ones, with respect to the starting dichlrorides.
- Leushina, Evgenia,Tikhomirova, Ksenia,Permyakova, Anastasiya,Ilin, Pavel,Terenina, Maria,Anisimov, Alexander,Khoroshutin, Andrey
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p. 149 - 155
(2016/03/19)
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- Unusual multistep reaction of C70Cl10 with thiols producing C70[SR]5H
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We report a reaction of the chlorofullerene C70Cl10 with thiols producing C70[SR]5H with all organic addends attached around one central pentagon at the pole of the C70 cage. This reaction was shown to proceed via a complicated radical pathway, presumably involving addition, substitution, rearrangement, and/or elimination steps. The obtained C70[SR]5H products were shown to be very unstable and undergo quantitative decomposition to pristine C70, RSSR, and RSH at elevated temperatures (e.g., 50 °C). Quantum chemical calculations and NMR spectroscopy data showed that cleavage of organic addends from the fullerene cage could be induced by solvation effects in solution.
- Khakina, Ekaterina A.,Peregudov, Alexander S.,Yurkova, Anastasiya A.,Piven, Natalya P.,Shestakov, Alexander F.,Troshin, Pavel A.
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p. 1215 - 1219
(2016/03/01)
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- Microwave-Assisted Pd-Catalyzed Desulfitative C-S Coupling of Arylsulfinate Metal Salts and Alkanethiols
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This paper reports a palladium-catalyzed C-S coupling of arylsulfinate metal salts and alkanethiols via liberation of sulfur dioxide. The use of PdCl2 as the catalyst in combination with AgNO3 as the oxidant under microwave irradiation results in the synthetically and biologically important aryl alkyl sulfides. A variety of arylsulfinate metal salts, such as sodium, potassium, lithium, silver, zinc, and copper salts, are tolerated well in this reaction.
- Li, Junchen,Bi, Xiaojing,Wang, Hongmei,Xiao, Junhua
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p. 1873 - 1881
(2015/11/02)
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- The thiocarbonyl 'S' is softer than thiolate 'S': A catalyst-free one-pot synthesis of isothiocyanates in water
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Treatment of the preformed or the in situ generated aryl/alkyl dithiocarbamates triethylammonium salt (ArNHCSS-.Et 3NH+) with methyl acrylate in an aqueous medium gave solely arylisothiocyanate (ArNCS), whereas the in situ generated aryl dithiocarbamic acid (ArNHCSS-.H+) yielded exclusively the thia-Michael adduct (ArNHCSSCH2CH2COOMe). This differential reactivity can be explained by two alternative mechanisms which is dependent both on the nature of the counter cation and on the pH of the reaction medium. Irrespective of the counter cations, the thiocarbonyl sulfur (=S) atom, having large orbital-coefficient, is softer compared to the thiol/thiolate sulfur (-SH/S-) in a dithiocarbamate salt and the former adds to the Michael acceptor by a 1,4-addition.
- Jamir, Latonglila,Ali, Abdur Rezzak,Ghosh, Harisadhan,Chipem, Francis A. S.,Patel, Bhisma K.
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body text
p. 1674 - 1678
(2010/07/04)
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- ALKOXYPROPYL ISOTHIAZOLINONE AND PREPARATION METHOD AND USE THEREOF
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An alkoxylpropyl isothiazolinone of formula: C6H6Cl2NO2SR, in which R is CH3, CH2CH3, CH(CH3)2, CH2CH2CH2CH3, CH2CH2OCH3 or CH2CH2OC6H5Cl. A method for preparing the isothiazolinone by reacting sodium polysulphide with methyl acrylate to obtain dimethyl dithiodipropionate, followed by aminolysis with alkoxyl propylamine to obtain N,N'-dialkoxylpropyldithio-dipropionamide, which is then reacted with sulfuric chloride. The alkoxylpropyl-isothiazolinone of the invention can be used for preparing marine antifouling paint coating as antifoulant, and also used as antiseptics.
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Page/Page column 3
(2008/06/13)
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- Oxidation/reduction interconversion of thiols and disulfides using hydrogen and oxygen catalyzed by a rhodium complex
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RhH(PPh3)4 catalyzes reduction of disulfides to thiols by hydrogen and RhH(PPh3)4/1,4- bis(diphenylphosphino)butane (dppb) catalyzes oxidation of thiols to disulfides by oxygen.
- Arisawa, Mieko,Sugata, Chiyoshi,Yamaguchi, Masahiko
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p. 6097 - 6099
(2007/10/03)
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- Process for the preparation of organic disulphides and polysulphides
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The invention relates to the preparation of organic disulphides and polysulphides by the action of sulphur on a mercaptan or on a polysulphide which is lower in sulphur, in the presence of a basic catalyst. In the process according to the invention, an anion exchange resin is used as catalyst.
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- Conversion of Hydroxyl Groups in Alcohols to Other Functional Groups with N-Hydroxy-2-thiopyridone, and Its Application to Dialkylamines and Thiols
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The radical decarboxylation reaction of N-alkoxyoxalyloxy-2-thiopyridone which was prepared by the reaction of alcohol, oxalyl chloride, and N-hydroxy-2-thiopyridone was studied both in the absence and presence of olefinic compounds.The same reactions with olefinic and acetylenic alcohols gave the corresponding lactone derivatives.On the other hand the unsymmetrical alkyl 2-pyridyl disulfides were obtained by the same reaction with aliphatic thiols.
- Togo, Hideo,Fujii, Misa,Yokoyama, Masataka
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- CONVENIENT METHOD FOR THE PREPARATION OF 3-(2-PYRIDYL DITHIO) PROPIONIC ACID N-HYDROXY SUCCINIMID ESTER
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A new efficient and simple method for the preparation of 3-(2-pyridyl dithio) propionic acid N-hydroxy succinimid ester using diethyl azo dicarboxylate, is described.
- Loccufier, J.,Schacht, E.
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p. 535 - 540
(2007/10/02)
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- SULFONYL ESTERS 1: THE REDUCTION OF TRIBROMOPHENYL SULFONATES WITH MERCAPTIDE ANIONS
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2,4,6-tribromophenyl sulfonates have been shown to undergo unusually efficient reduction by mercaptide anions in hexamethylphosphoramide.The reduction products include the sulfinate anion derived from the sulfonate ester and the disulfide derived from the mercaptide anions.
- Durkin, Kathleen Anne,Langler, Richard Francis,Morrison Nancy Ann
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p. 3070 - 3076
(2007/10/02)
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- Preparation of dialkyl dithiodialkanoates
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A method for obtaining dialkyl dithiodialkanoates in which mercaptoalkyl esters are contacted with a halogen in an inert hydrocarbon solvent to produce a heavy liquid phase of dialkyl dithiodialkanoate and a separate liquid phase of hydrocarbon solvent. These phases are easily separated into the product dialkyl dithiodialkanoate and hydrocarbon solvent which can be recycled without further treatment. In an embodiment of the invention the dialkyl dithiodialkanoate is further contacted with alkylene oxide to neutralize residual acidic by-products in the reaction mixture.
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