- Highly uniform self-assembled monolayers of silver nanospheres for the sensitive and quantitative detection of glutathione by SERS
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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.
- Chen, Yi,Huang, Feixiang,Jiang, Cailing,Jiang, Li
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supporting information
p. 10436 - 10445
(2021/08/09)
-
- Integrated preparation method of 2-mercaptopyridine and 2, 2 '-pyridinium sulfide
-
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.
- -
-
Paragraph 0037-0045
(2021/09/15)
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- Washington Red (WR) dyes and their imaging applications
-
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.
- Chen, Wei,Xian, Ming
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p. 149 - 163
(2020/06/08)
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- Promoting Effect of Crystal Water Leading to Catalyst-Free Synthesis of Heteroaryl Thioether from Heteroaryl Chloride, Sodium Thiosulfate Pentahydrate, and Alcohol
-
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.
- Ma, Xiantao,Yu, Jing,Yan, Ran,Yan, Mengli,Xu, Qing
-
supporting information
p. 11294 - 11300
(2019/09/12)
-
- Copper-Catalyzed Direct Synthesis of Aryl Thiols from Aryl Iodides Using Sodium Sulfide Aided by Catalytic 1,2-Ethanedithiol
-
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.
- Xue, Hongyu,Jing, Bing,Liu, Shasha,Chae, Junghyun,Liu, Yajun
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p. 2272 - 2276
(2017/10/06)
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- Hydropersulfides: H-Atom Transfer Agents Par Excellence
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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.
- Chauvin, Jean-Philippe R.,Griesser, Markus,Pratt, Derek A.
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supporting information
p. 6484 - 6493
(2017/09/12)
-
- Efficient Generation of C–S Bonds via a By-Product-Promoted Selective Coupling of Alcohols, Organic Halides, and Thiourea
-
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.).
- Ma, Xiantao,Yu, Lei,Su, Chenliang,Yang, Yaqi,Li, Huan,Xu, Qing
-
supporting information
p. 1649 - 1655
(2017/05/29)
-
- Deoxygenation of amine N-oxides using gold nanoparticles supported on carbon nanotubes
-
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.
- Donck, Simon,Gravel, Edmond,Shah, Nimesh,Jawale, Dhanaji V.,Doris, Eric,Namboothiri, Irishi N. N.
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p. 50865 - 50868
(2015/06/25)
-
- Targeted and armed oncolytic adenovirus via chemoselective modification
-
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.
- Banerjee, Partha S.,Zuniga, Edison S.,Ojima, Iwao,Carrico, Isaac S.
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supporting information; experimental part
p. 4985 - 4988
(2011/10/09)
-
- Reduction of amine N-oxides by diboron reagents
-
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.
- Kokatla, Hari Prasad,Thomson, Paul F.,Bae, Suyeal,Doddi, Venkata Ramana,Lakshman, Mahesh K.
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experimental part
p. 7842 - 7848
(2011/12/01)
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- NOVEL AROMATIC COMPOUND AND POLYARYLENE COPOLYMER HAVING NITROGEN-CONTAINING HETEROCYCLE INCLUDING SULFONIC ACID GROUP IN SIDE CHAIN
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Provided is a solid polymer electrolyte having increased heat resistance and high proton conductivity and a proton conductive membrane composed of the electrolyte. Also provided is a copolymer having a sulfonic acid group. The copolymer includes a repeating unit represented by Formula (1): (in the formula, Y denotes at least one kind of structure selected from the group consisting of —CO—, —SO2—, —SO—, —CONH—, —COO—, —(CF2)l— (l is an integer of 1 to 10), and —C(CF3)2—; W denotes at least one kind of structure selected from the group consisting of a direct bond, —CO—, —SO2—, —SO—, —CONH—, —COO—, —(CF2)l— (l is an integer of 1 to 10), —C(CF3)2—, —O—, and —S—; Z denotes a direct bond or at least one kind of structure selected from the group consisting of —(CH2)l—(l is an integer of 1 to 10), —C(CH3)2—, —O—, —S—, —CO—, and —SO2—; R30 denotes a nitrogen-containing aromatic ring having a substituent represented by —SO3H, —O(CH2)hSO3H, or —O(CF2)hSO3H (h is an integer of 1 to 12); p is an integer of 0 to 10; q is an integer of 0 to 10; r is an integer of 1 to 5; and k is an integer of 0 to 4).
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-
- Exofacial protein thiols as a route for the internalization of Gd(III)-based complexes for magnetic resonance imaging cell labeling
-
Four novel MRI Gd(III)-based probes have been synthesized and evaluated for their labeling properties on cultured cell lines K562, C6, and B16. The labeling strategy relies upon the fact that cells display a large number of reactive exofacial protein thio
- Digilio, Giuseppe,Menchise, Valeria,Gianolio, Eliana,Catanzaro, Valeria,Carrera, Carla,Napolitano, Roberta,Fedeli, Franco,Aime, Silvio
-
experimental part
p. 4877 - 4890
(2010/10/19)
-
- Size-dependence of Fermi energy of gold nanoparticles loaded on titanium(iv) dioxide at photostationary state
-
TiO2 particle-supported Au nanoparticles (NPs) with varying sizes and good contact (Au/TiO2) were prepared under a constant loading amount by the deposition-precipitation method. The Fermi energy of Au NPs loaded on TiO2 a
- Kiyonaga, Tomokazu,Fujii, Masashi,Akita, Tomoki,Kobayashi, Hisayoshi,Tada, Hiroaki
-
experimental part
p. 6553 - 6561
(2009/04/05)
-
- Novel N,S-phenacyl protecting group and its application for peptide synthesis
-
The phenacyl group can be introduced onto amino and thio groups by N,S-alkylation reactions. Conversely, these groups are removed rapidly by employing magnesium in acetic acid. This protecting group was successfully applied to a short peptide synthesis of Boc-L-Cys-Gly-OMe. Georg Thieme Verlag Stuttgart.
- Tang, Guo,Ji, Tao,Hu, An-Fu,Zhao, Yu-Fen
-
experimental part
p. 1907 - 1909
(2009/04/11)
-
- Pharmaceutical composition containing liposomes for treating cancer
-
The present invention provides liposome-containing drug administration carriers that have improved residence time in the blood and improved migration into tumor cells as compared with conventional ones and that have reduced accumulation in the heart, and
- -
-
Page/Page column 10
(2008/06/13)
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- Heteroaryl thioglycosides, a new class of substrates for glycosidases
-
We have found that heteroaryl thioglycosides are useful substrates of β-glucosidase from almond and can act as a new class of donors in transglycosylation reaction.
- Niemiec-Cyganek,Szeja
-
p. 969 - 973
(2007/10/03)
-
- Cosmetic composition forming a tackifying coating comprising a polymer with a non-silicone skeleton and reactive functional groups
-
Cosmetic compositions, comprising at least one polymer with a non-silicone skeleton, comprising at least two reactive chemical functional groups, that is capable of forming a tackifying coating on the hair, a cosmetic process comprising the application of the composition to the hair, and also its use for producing a tackifying coating on the hair.
- -
-
-
- Cosmetic composition forming a soft coating comprising a polymer having a non-silicone backbone and reactive functional groups
-
Nontacky cosmetic compositions, such as hair compositions, comprising at least one polymer having a non-silicone backbone, comprising at least two reactive chemical functional groups, capable of forming a soft coating on hair, a cosmetic process comprising the application of this composition to hair and its use for producing a soft coating on hair.
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-
-
- Cosmetic composition forming a rigid coat, comprising a polymer with a non-silicone skeleton and containing reactive functional groups
-
Cosmetic compositions, such as hair compositions, comprising at least one polymer with a non-silicone skeleton, comprising at least two reactive chemical functional groups, which are capable of forming a rigid coat on the hair, a cosmetic process comprising the application of this composition onto the hair, and its use for producing a rigid coat on the hair.
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-
- Synthesis of pyridothietone by flash vacuum pyrolysis of 2-mercaptonicotinic acid
-
The temperature dependence of products formed from flash vacuum pyrolysis (FVP) of 2-mercaptonicotinic acid 4 has been studied. FVP of 4 at 550°C and ca. 1×10-2 torr gave pyridothietone 3b and a trimer 5 as the major products. At higher temperature (800°C), FVP of 4 gave 2-mercaptopyridine 6 as the major product and 2,2′-dipyridyl disulphide 7 as the minor one.
- Chou, Chin-Hsing,Chiu, Shao-Jung,Liu, Wei-Min
-
p. 5285 - 5286
(2007/10/03)
-
- Instant degradation of plastics into soluble non-toxic products
-
The present invention describes novel, cost-effective and rapid processes suitable for degradation and recycling of specially designed plastics, which are defined as instantly degradable synthetic polymeric plastics having the characteristics and properties of conventional forms of plastics. These novel plastic products are made from a variety of compositions of polymers and their compatible nontoxic modifiers. The resulting novel instant degradable plastic products retain latent solubility properties which are triggered upon mild chemical processes of the present invention, thus enabling cost effective and facile recycling of plastic refuge.
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-
- A general palladium-catalysed synthesis of aromatic and heteroaromatic thioethers
-
Thioethers can be efficiently prepared via palladium-catalysed cross-coupling of arene- or heteroarene thiols with arene- or heteroarene iodides. A simple, cheap and robust catalytic system is described that couples a broad range of electron-deficient as well as electron-rich substrates in high yield.
- Schopfer, Ulrich,Schlapbach, Achim
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p. 3069 - 3073
(2007/10/03)
-
- The effect of nanometre-sized Au particle loading on TiO2 photocatalysed reduction of bis(2-dipyridyl)disulfide to 2-mercaptopyridine by H2O
-
TiO2 photocatalysed reduction of bis(2-dipyridyl)disulfide (RSSR) to 2-mercaptopyridine by H2O is enhanced significantly by incorporation of nanometre-sized Au particles. The rate is strongly dependent on the amount of Au loaded (x w
- Tada,Suzuki,Yoneda,Ito,Kobayashi
-
p. 1376 - 1382
(2007/10/03)
-
- Precious metal composition
-
Gold thiolates of formula AuSR'' or a salt thereof, in which R'' is such that HSR'' represents: 4,6-dihydroxy-2-mercaptopyrimidine; N-(2-mercaptoacetyl)glycine; N-(3-mercaptopropionyl)glycine; and N-(2-mercaptopropionyl)glycine. The invention provides also processes for preparing novel gold thiolates.
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-
- A rapid and efficient cleavage of organic disulfides to mercaptans using ZrCl4/NaBH4
-
A practical and cheaper reagent system ZrCl/NaBH4 is used for the reductive cleavage of organic disulfides to mercaptans under mild conditions, in excellent yields.
- Purushothama Chayr,Rajaram,Iyengar
-
p. 3905 - 3911
(2007/10/03)
-
- TiO2 photocatalytic reduction of bis(2-dipyridyl)disulfide to 2-mercaptopyridine by H2O: Incorporation effect of nanometer-sized Ag particles
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A highly endothermic reduction of bis(2-dipyridyl)disulfide to 2-mercaptopyridine by H2O selectively proceeds using TiO2 as a photocatalyst, being significantly enhanced upon incorporation of nanometer-sized Ag particles on TiO2
- Tada, Hiroaki,Teranishi, Kazuaki,Inubushi, Yo-Ichi,Ito, Seishiro
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p. 2345 - 2346
(2007/10/03)
-
- Nucleophilic properties of thiourea towards aromatic halides
-
Arylsulfides (and diaryldisulfides obtained spontaneously by oxidation of the arylsulfides during the work-up) and diarylsulfides can be obtained by substituting aryl radicals by the thiourea onion in liquid ammonia under an electrochemical inducement.
- Combellas,Dellerue,Mathey,Thiebault
-
p. 539 - 542
(2007/10/03)
-
- Intramolecular Addition of a Dioxolanyl Radical to the Indole Nucleus: Preparation of Enantiomerically Pure, Oxygenated Perhydro-3H-pyrroloindoles
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The cyclization of dioxolanyl radicals, which were generated by the Barton tartrate-derived thiohydroxamate ester (mixed anhydride) procedure, with an indole nucleus has been explored.The products derived from these reactions have been identified and their chemistry investigated with the goal of uncovering new entries into enantiomerically pure, mitomycin-like structures.Thus, the photolysis of 1-hydroxy-2-thiopyridone ester 8c and 1-hydroxy-4-methylthiazole-2(3H)-thione ester 8d has been conducted with UV and visible light.The photochemistry of the products, namely, dimer 9, dihydroindole 12a, indole 11, and thiazole 13c, derived from the thiohydroxamate esters and putative intermediates 18a and 18b, was also explored.
- Ziegler, Frederick E.,Harran, Patrick G.
-
p. 2768 - 2773
(2007/10/02)
-
- Deoxydative Thiation of 3-Substituted Pyridine N-Oxides with 4-Methoxytoluene-α-thiol: A Divergent Route to Pyridinethiols
-
Synthesis of 3-substituted 2-pyridinethiols was achieved by thiation of pyridine N-oxides with 4-methoxytoluene-α-thiol in the presence of diethylcarbamoyl chloride followed by cleavage of the resulting sulfides.The case of substitution was shown to be affected by nucleophilicity of the N-oxide oxygen.Addition of zinc bromide to the reaction, a need for triethylamine, decreased most of the yield for thiation products but the formation of 3-methoxy-2-methoxybenzylthiopyridine was only improved.A plausible mechanism of the substitution, particularly β-thiation to the N-oxide function, is discussed compared with the regiochemistry observed in the reaction with diethoxyphosphoryl chloride instead of diethylcarbamoyl chloride.The debenzylation to pyridinethiol was also found to be dependent on the electron-density in the pyridine ring.
- Sato, Nobuhiro,Nagano, Eiichi
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p. 691 - 698
(2007/10/02)
-
- Toxin-targeted design for anticancer therapy. I: Synthesis and biological evaluation of new thioimidate heterobifunctional reagents
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In an effort to obtain a more potent and specific immunotoxin for cancer therapy, we designed a series of heterobifunctional linkers characterized by a thioimidate group linked to a S-acetyl thiol (4, 5) or substituted aryldithio group (6-10). These ligands were synthesized by a Pinner-type process from the corresponding nitrile derivatives obtained by thiol- disulphide exchange reaction, reaction with substituted benzene-sulphenyl chloride, or other known procedures. To check the reagent of choice for immunoconjugate preparation, we studied thioldisulphide exchange kinetics between the intermediate nitrile derivatives and cysteine. Among the tested aryldithio derivatives (6-10), we selected ethyl 3-(4-carboxamido- phenyldithio)propionthioimidate (CDPT, 9) for further studies. By analyzing the rate of incorporation of the linkers 4, 5, and 9 in a model immunoglobulin G protein, we found similar results with CDPT 9 and ethyl S- acetyl 3-mercaptopropionthioimidate ester hydrochloride (AMPT, 5) because both reagents showed a linear correlation between the number of introduced thiol groups and factors such as time and protein and reagent concentrations. Comparison of the two acetylthio-derivative ligands 4 and 5 showed that AMPT 5 was more stable toward deacetylation than ethyl S-acetyl 2- mercaptopropionthioimidate ester hydrochloride (AMAT, 4). By comparing the kinetic and biological parameters of seven new thioimidate linkers, we found that two of these (CDPT and AMPT) could be superior ligands for protein- protein conjugation. They offer advantages over the commercially available compounds, such as minimal perturbation of the protein structure, controlled reactivity, and good stability.
- Delprino,Giacomotti,Dosio,Brusa,Ceruti,Grosa,Cattel
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p. 506 - 512
(2007/10/02)
-
- A New Procedure for the Conversion of Thiols into Reactive Sulfenylating Agents
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Thiols may be converted in high yield into unsymmetrical 2-pyridyl disulfides 3.Treatment of these with alkylating agents (e.g., alkyl fluorosulfonates or oxonium salts) affords the corresponding N-alkylpyridyl disulfides 4, which are potent sulfenylating agents (Scheme II) and react smoothly with a variety of sulfur nucleophiles (e.g., thiols, thiones, thioamides, dithiocarbamates, thiocyanate, etc.) to afford disulfides, with amines to afford sulfenamides, and with β-diketones to afford sulfides.This new method is particularly well-suited to the preparation of unsymmetrical disulfides and sulfenamides from complex and otherwise r eactive thiols.
- Barton, D. H. R.,Hesse, R. H.,O'Sullivan, A. C.,Pechet, M. M.
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p. 6697 - 6702
(2007/10/02)
-
- Process for preparing penems
-
During the preparation of 6-(substituted methylene)-2-penem compounds (which are known for their anti-bacterial and β-lactamase inhibitory properties) mixtures of the E-isomer and the Z-isomer may be formed. The Z-isomer is, however generally preferred, and the present invention provides a process whereby the E-isomer may be converted into the Z-isomer by reaction with an aromatic heterocyclic thiol in the presence of a base.
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-
-
- Rhodium(III) Complexes with Pyridine-2-thiol (pySH) and Pyridine-2-thiolato (pyS) as the only Ligands: Crystal Structures of mer-, Cl*0.5H2O, and
-
The rhodium(I) compound reacts with an excess of pyridine-2-thiol (pySH) in air to give orange crystals of the oxidised product Cl, the single-crystal X-ray structure of which shows two chelating ligands pyS- in an equatorial plane with mutually cis sulphur atoms.The monodentate neutral ligands (pySH) are trans co-ordinated through sulphur and are linked through NH...Cl-...HN hydrogen bonds to form a large pseudo-chelate ring.The neutral red compound is formed only slowly following rapid deprotonation of the cation by basic alumina or NEt3.The X-ray structure shows that a gross stereochemical change has occured so that two monodentate ligands (pySH and pyS-) are cis while the two chelating ligands (pyS-) have mutually trans sulphur atoms.The deprotonation, with its associated stereochemical change, is reversible.The action of heat on gives free pySH and mer- (X-ray structure reported), which may also be obtained directly from RhCl3*3H2O and pySH in the presence of base.
- Deeming, Antony J.,Hardcastle, Kenneth I.,Meah, M. Nafees,Bates, Paul A.,Dawes, Helen M.,Hursthouse, Michael B.
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p. 227 - 234
(2007/10/02)
-
- The reduction of specific disulfides with titanium(III) chloride
-
The reaction between titanium(III) chloride and disulfides was investigated.Aryl and alkyl disulfides did not react while heterocyclic aromatic disulfides with a nitrogen α to the sulfur were reduced to the corresponding thiols.Products were identified and characterized by nuclear magnetic resonance and inrared spectra; and melting point comparisons with authentic compounds.The reductions occurred only in the presence of citrate and were found to require 2 moles of titanium(III) per mole of disulfide.
- Akers, Hugh A.,Vang, Meng C.,Updike, Tracie D.
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p. 1364 - 1366
(2007/10/02)
-
- New Amino-protective Reagents for t-Butoxycarbonylation and Benzyloxycarbonylation of Amines and Amino Acids
-
New amino-protective reagents for t-butoxycarbonylation and benzyloxycarbonylation of amines and amino acids have been developed. t-Butyl 2-pyridyl carbonate and t-butyl S-(2-pyridyl) thiocarbonate react cleanly with various amines and amino acids to afford N-Boc amines and N-Boc amino acids in high yields.Benzyl 2-pyridyl carbonate and O-benzyl S-(2-pyridyl) thiocarbonate are also found to be very effective in the benzyloxycarbonylation of amino acids.
- Kim, Sunggak,Lee, Jae In,Yi, Kyu Yang
-
p. 3570 - 3575
(2007/10/02)
-
- THE REACTION OF 2,2'-DIPYRIDYL SULFIDE WITH PHENOL
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The reaction of 2,2'-dipyridyl sulfide with phenol affords 2-pyridinethiol and phenyl 2-pyridyl ether, which is the aromatic ipso substitution in 2,2'-dipyridyl sulfide by the phenoxy group.On the other hand, pyridyl tolyl sulfide is formed by the reaction of phenyl pyridyl ether with toluenethiol.
- Inoue, Shordoh
-
p. 141 - 144
(2007/10/02)
-
- Syntheses of Mercaptobenzoic Acids and Mercaptopyridines Using Elemental Sulfur in the Presence of NaOH-KOH
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Mercaptobenzoic acids and mercaptopyridines were synthesized by using mercaptylation of halogeno compounds with elemental sulfur in the presence of molten salts (NaOH-KOH).This procedure was also applied to the preparation of selenoaryl compounds by using elemental selenium.Based on the behavior of the molten salts and sulfur, Na2S and K2S were considered to be the active species for the mercaptylation.KEYWORDS-mercaptylation; molten salt; o-mercaptobenzoic acid; o-selenobenzoic acid; 2-mercaptopyridine
- Kamiyama, Tsutomu,Enomoto, Saburo,Inoue, Masami
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p. 5184 - 5189
(2007/10/02)
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- REDUCTION OF SULFONIC ACIDS WITH TRIPHENYLPHOSPHINE-DIARYL DISULFIDE SYSTEM.
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Diaryl disulfides are effective catalysts to reduce arenesulfonic acids with triphenylphosphine to the corresponding arenethiols in good yields, while alkanesulfonic acids are transferred into the corresponding alkyl aryl sulfides. Arenesulfonic acids bearing electron-donating substituents can be reduced more readily than those having electron-withdrawing substituents, while diaryl disulfides bearing electron-withdrawing substituents are more effective catalysts than diaryl disulfides with electron-donating ring substituents.
- Oae,Togo
-
p. 232 - 236
(2007/10/02)
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- Quantitative Model of Solvent Effects on Hydroxypyridine-Pyridone and Mercaptopyridine-Thiopyridone Equilibria: Correlation with Reaction-Field and Hydrogen-Bonding Effects
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A model for the effect of reaction field and hydrogen bonding on the relative energies of protomers is applied to the equilibria between 6-chloro-2-hydroxypyridine and 6-chloro-2-pyridone, 2-mercaptopyridine and 2-thiopyridone, 6-chloro-2-mercaptopyridine and 6-chloro-2-thiopyridone, and 4-mercaptopyridine and 4-thiopyridone in a wide range of solvents.Quantitative correlation is obtained by a multivariable analysis.In addition to satisfactory statistical tests of the correlations, estimates of the differences in free energies between the isomers in the vapor phase and of the dipole moment component of the reaction-field term are obtained which compare well with the available independent values.These criteria are shown to signal an unacceptable correlation for the case of 2-chloro-4-hydroxypyridine and 2-chloro-4-pyridone.The advantage of this model, which provides an understanding of the effect of molecular environment on protomeric equilibria in terms of reasonable physical interactions, over empirical approaches is noted.
- Beak, Peter,Covington, Johnny B.,White, J. Matthew
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p. 1347 - 1353
(2007/10/02)
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- Displacement of Protomeric Equilibria by Self-Association: Hydroxypyridine-Pyridone and Mercaptopyridine-Thiopyridone Isomer Pairs
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Values of both self-association and protomeric equilibrium constants are reported for 2-hydroxypyridine-2-pyridone, 4-hydroxypyridine-4-pyridone, and 2-mercaptopyridine-2-thiopyridone isomer pairs in different solvents.These results provide quantitative evidence for significant differences in the positions of protomeric equilibria for self-associated and monomeric species.The 2-substituted isomers are associated as well-known dimers while the 4-substituted systems form oligomers.In polar and hydrogen-bonding solvents self-association is substantially reduced.Sterically hindered 2- and 4-pyridones are less associated than unhindered systems.The implication of these results, that determinations and interpretations of protomeric equilibrium should take into account the possible dominance of self-association, is discussed.
- Beak, Peter,Covington, Johnny B.,Smith, Stanley G.,White, J. Matthew,Zeigler, John M.
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p. 1354 - 1362
(2007/10/02)
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- A DIRECT SYNTHESIS OF HETEROCYCLIC THIOLS
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Heterocyclic thiols (thiones) are conveniently synthesized in good yields by the reaction of heterocyclic halides with sodium thiosulfate.The reaction requires the presence of acid, either added or liberated during the reaction, to hydrolyze the intermediate thiosulfate to thiol.
- Foye, William O.,Abood, Norman,Kauffman, Joel M.,Kim, Young-Ho,Patel, Bhupendra R.
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p. 205 - 208
(2007/10/02)
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- Cephalosporin displacement reaction
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The present invention is directed to a process for the displacement of the acetoxy group of a cephalosporanic acid by a sulfur nucleophile, in an organic solvent and under essentially anhydrous conditions.
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- Acylamino-cephem-carboxylic acids containing an amidino or guanidino group in the molecule
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Acylamino-cephem-carboxylic acids of the formula I STR1 in which R1, R2 and R3 represent hydrogen or alkyl, R1 and R2 or R2 and R3 together may form an alkylene radical which may be substituted, X represents a single bond or NH, A represents a phenylene or thienylene radical which may be substituted, Y represents a single bond or oxygen and Z represents a 5- or 6-membered ring which may be substituted and which may be bound to an anellated ring system, and their physiologically tolerated salts and esters, a process for preparing these compounds and preparations containing them.
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- Hexakis(2-pyridylthio)tetrazinc monooxide
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A novel 2-pyridylthiozinc-oxide complex, hexakis (2-pyridylthio)tetrazinc monooxide, which can protect a polyolefin against thermal and oxidative deterioration, particularly against deterioration caused by contact with heavy metals, is disclosed. Various
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- Pesticidal compositions containing phosphoric esters and divalent sulphur compounds
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Pesticidal composition comprising: a pesticidal, phosphoric ester the molecule of which has at least one alkyl group of 1 to 3 carbon atoms, 0.05 to 10% of an agent stabilizing the said ester against decomposition by protonisation, together with adjuvants characterized in that the stabilizing agent comprises at least one sulphur compound containing per molecule at least one divalent sulphur atom of which one valence is bonded to an atom chosen from sulphur, carbon, nitrogen, hydrogen, and metals capable of giving a salt, the other valence being bonded to an atom chosen from hydrogen, the carbon atom already noted, a second carbon atom, the nitrogen atom already noted, a second nitrogen atom, the metal atom already noted in the case of a metal of valence greater than one, a second atom of metal and oxygen when the first valence is not attached to an atom of hydrogen, the proportion of sulphur calculated with reference to the weight of the sulphur compound being between 5 and 99%. Process for stabilizing a phosphoric ester of which the molecule possesses at least one alkyl group containing 1 to 3 carbon atoms characterized in that there is added to the phosphoric ester or to a mixture which contains it, 0.05 to 10% calculated on the weight of the phosphoric acid ester of an agent capable of stabilizing the said phosphoric ester against protonisation and comprising at least one sulphur compound such as that defined thereupon.
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- 7-(3-Substituted ureido) cephalosporins
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Cephalosporin compounds with 3-substituted ureido or -thioureido group at position 7 and hydrogen or heterocyclicthiomethyl groups at position 3 are prepared. These compounds are antibacterial agents.
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