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Spontaneous substitution of azulene-derived benzylic alcohols by thiols and its application to labeling/protection of biothiols
By mixing guaiazulene-3-methanol derivatives and thiols at room temperature, benzylic substitution of the alcohol proceeded to yield the corresponding sulfide. Because of the blue color of the guaiazulene derivative, this spontaneous reaction was used for labeling of paper-immobilized biothiols. By treatment with tris(2-carboxyethyl)phosphine hydrochloride, the guaiazulene-3-ylmethyl part of the sulfide could be removed and the original thiol recovered. Based on these findings, a guaiazulene-3-methanol derivative was used as a protective group for the synthesis of cysteine derivatives.
Jin, Yu,Akagawa, Kengo,Kudo, Kazuaki
supporting information

(2021/02/27)

Sulfur Incorporation Using Disulfanes as the Sulfur Atom Source Enabled Metal-Free Heteroannulation of 1,7-Enynes
A new oxidative [2+2+1] heteroannulation of 1,7-enynes with disulfanes promoted by Et3N, producing 3,3a-dihydro-thieno[3,4-c]quinolin-4(5H)-ones, is described. This reaction is achieved by using equivalent amounts of 1,7-enynes, sulfur atoms (disulfanes), tert-butyl peroxybenzoate (TBPB) as an oxidant and Et3N as the base, and represents an unprecedented strategy to applications of disulfanes as sulfur atom sources in synthesis. (Figure presented.).
Qin, Jing-Hao,Yu, Jiang-Xi,Li, Jin-Heng,An, De-Lie
supporting information
p. 3974 - 3979
(2019/08/01)

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
p. 2272 - 2276
(2017/10/06)

Nitromethane as a cyanating reagent for the synthesis of thiocyanates
Nitromethane has been developed to be an effective cyanating reagent for the synthesis of thiocyanates. In the presence of iodine and base, a wide range of disulfides were reacted with nitromethane smoothly to give diverse thiocyanates in moderate to good yields.
Wang, Zuo-Hui,Ji, Xiao-Ming,Hu, Mao-Lin,Tang, Ri-Yuan
p. 5067 - 5070
(2015/08/06)

Copper(II)-Catalyzed Single-Step Synthesis of Aryl Thiols from Aryl Halides and 1,2-Ethanedithiol
A highly efficient transition metal-catalyzed single-step synthesis of aryl thiols from aryl halides has been developed employing copper(II) catalyst and 1,2-ethanedithiol. The key features are use of readily available reagents, a simple operation, and relatively mild reaction conditions. This new protocol shows a broad substrate scope with excellent functional group compatibility. A variety of aryl thiols are directly prepared from aryl halides in high yields. Furthermore, the aryl thiols are used in situ for the synthesis of more advanced molecules such as diaryl sulfides and benzothiophenes.
Liu, Yajun,Kim, Jihye,Seo, Heesun,Park, Sunghyouk,Chae, Junghyun
supporting information
p. 2205 - 2212
(2015/07/27)

Tris(3-hydroxypropyl)phosphine (THPP): A mild, air-stable reagent for the rapid, reductive cleavage of small-molecule disulfides
Tris(3-hydroxypropyl)phosphine (THPP) is demonstrated to be a versatile, water-soluble and air-stable reducing agent, allowing for the rapid, irreversible reductive cleavage of disulfide bonds in both aqueous and buffered aqueous-organic media. The reagent shows exceptional stability at biological pH under which condition it permits the rapid reduction of a wide range of differentially functionalized small-molecule disulfides.
McNulty, James,Krishnamoorthy, Venkatesan,Amoroso, Dino,Moser, Michael
p. 4114 - 4117
(2015/11/03)

Development of selective colorimetric probes for hydrogen sulfide based on nucleophilic aromatic substitution
Hydrogen sulfide is an important biological signaling molecule and an important environmental target for detection. A major challenge in developing H2S detection methods is separating the often similar reactivity of thiols and other nucleophiles from H2S. To address this need, the nucleophilic aromatic substitution (SNAr) reaction of H2S with electron-poor aromatic electrophiles was developed as a strategy to separate H2S and thiol reactivity. Treatment of aqueous solutions of nitrobenzofurazan (7-nitro-1,2,3-benzoxadiazole, NBD) thioethers with H 2S resulted in thiol extrusion and formation of nitrobenzofurazan thiol (λmax = 534 nm). This reactivity allows for unwanted thioether products to be converted to the desired nitrobenzofurazan thiol upon reaction with H2S. The scope of the reaction was investigated using a Hammett linear free energy relationship study, and the determined ρ = +0.34 is consistent with the proposed SN2Ar reaction mechanism. The efficacy of the developed probes was demonstrated in buffer and in serum with associated submicromolar detection limits as low as 190 nM (buffer) and 380 nM (serum). Furthermore, the sigmoidal response of nitrobenzofurazan electrophiles with H2S can be fit to accurately quantify H2S. The developed detection strategy offers a manifold for H2S detection that we foresee being applied in various future applications.
Montoya, Leticia A.,Pearce, Taylor F.,Hansen, Ryan J.,Zakharov, Lev N.,Pluth, Michael D.
p. 6550 - 6557
(2013/07/26)

Novel one-pot synthesis of thiophenols from related triazenes under mild conditions
In this work, at first, triazenes were synthesized from primary aryl amines. Afterwards, triazenes were converted into the corresponding thiophenols in one-pot using sodium sulfide in acidic media, by in situ generation of diazonium counterion beside hydrogen sulfide as anionic sulfur nucleophile at room temperature. The procedure can be a convenient shortcut for the preparation of thiophenols from primary aryl amines. Georg Thieme Verlag Stuttgart · New York.
Khazaei, Ardeshir,Kazem-Rostami, Masoud,Moosavi-Zare, Ahmadreza,Bayat, Mohammad,Saednia, Shahnaz
experimental part
p. 1893 - 1896
(2012/09/22)

A study of the kinetics of La3+-promoted methanolysis of S-aryl methylphosphonothioates: Possible methodology for decontamination of EA 2192, the toxic byproduct of VX hydrolysis
The kinetics of the La3+-catalyzed methanolysis of a series of S-aryl methylphosphonothioates (4a-e, phenyl substituents = 3,5-dichloro, 4-chloro, 4-fluoro, 4-H, 4-methoxy) were studied at 25 °C with ss pH control. The reaction involves saturation binding of the anionic substrates to dimeric La3+/methoxide catalysts formulated as La2 3+(-OCH3)x, where x = 2-5 depending on the solution ss pH. Cleavage of the La3+-bound methylphosphonothioates is fast, ranging from 5 × 10-3 s -1 to 5.5 × 10-5 s-1 for substrates 4a-e at a ss pH of 8.4 and 1.6 × 10-1 s-1 to 4 × 10-3s-1 at a ss pH of 11.7. The rate accelerations for the methanolysis of substrates 4a-e, relative to their background methoxide-promoted reactions, average 7 × 1010 and 1.5 × 109, respectively, at sspH's of 8.4 and 11.7. The catalytic system is predicted to cleave EA 2192 (S-2(N,N-di-iso-propylaminoethyl) methylphosphonothioate), a toxic byproduct of the hydrolysis of VX, with a t1/2 between 4 and 8 min at a ss pH of 8.4, and 27 min at a ss pH of 11.7.
Dhar, Basab B.,Edwards, David R.,Brown, R. Stan
experimental part
p. 3071 - 3077
(2011/05/09)

CuI-nanoparticles-catalyzed selective synthesis of phenols, anilines, and thiophenols from aryl halides in aqueous solution
CuI-nanoparticles-catalyzed selective synthesis of phenols, anilines, and thiophenols from aryl halides was developed in the absence of both ligands and organic solvents. Anilines were formed selectively with ammonia competing with hydroxylation and thiophenols were generated selectively with sulfur powder after subsequent reduction competing with hydroxylation and amination.
Xu, Hua-Jian,Liang, Yu-Feng,Cai, Zhen-Ya,Qi, Hong-Xia,Yang, Chun-Yan,Feng, Yi-Si
p. 2296 - 2300
(2011/06/17)

Copper-catalyzed coupling of thiourea with aryl iodides: The direct synthesis of aryl thiols
A general, economical and efficient protocol for the direct copper-catalyzed coupling of thiourea with aryl iodides is developed and it will be potentially applied in large-scale industry as a preferred process.
Qiao, Shu,Xie, Kun,Qi, Junsheng
scheme or table
p. 1441 - 1443
(2011/01/04)

Regio- and enantioselective intermolecular hydroacylation: Substrate-directed addition of salicylaldehydes to homoallylic sulfides
We report a Rh-catalyzed, regio- and enantioselective intermolecular olefin hydroacylation under mild conditions. Hydroacylations between homoallylic sulfides, containing a substrate-bound directing group, and salicylaldehyde derivatives occur in the presence of a spiro-phosphoramidite ligand, (R)-SIPHOS-PE, to give α-branched ketones in >20:1 selectivity and up to 97% ee. Our conditions are also applicable to the asymmetric intermolecular hydroacylation of 1,2-disubstituted olefins.
Coulter, Matthew M.,Kou, Kevin G. M.,Galligan, Baye,Dong, Vy M.
supporting information; experimental part
p. 16330 - 16333
(2011/02/23)

A general and efficient approach to aryl thiols: Cul-catalyzed coupling of aryl iodides with sulfur and subsequent reduction
A Cul-catalyzed coupling reaction of aryl iodides and sulfur powder takes place in the presence of K2CO3 at 90 °C. The coupling mixture is directly treated with NaBH4 or triphenylphosphine to afford aryl thiols in good to
Jiang, Yongwen,Qin, Yuxia,Xie, Siwei,Zhang, Xiaojing,Dong, Jinhua,Ma, Dawei
scheme or table
p. 5250 - 5253
(2009/12/28)

A simple, fast and chemoselective method for the preparation of arylthiols
An efficient and convenient method for the synthesis of arylthiols by reaction of sulfonyl chlorides with triphenylphosphine in toluene is reported.
Bellale, Eknath V.,Chaudhari, Mahesh K.,Akamanchi, Krishnacharya G.
experimental part
p. 3211 - 3213
(2010/03/01)

The unexpected desulfurization of 4-aminothiophenols
Thermolysis of 4-aminophenyl benzyl sulfide at 523 K in the hydrogen donor solvent (HDS), 9,10-dihydroanthracene (AnH2), gave 4-aminothiophenol and toluene as the predominant products of the homolytic S-C bond cleavage. Under these conditions, a portion of the 4-aminothiophenol was desulfurized to aniline with first-order kinetics and with a rate constant estimated by kinetic modeling to be 7.0 × 10-6 s-1. Starting with 4-NH2C6H4SH at 523 K, it was found that sulfur loss was more efficient in the non-HDSs, anthracene and hexadecane, than in AnH2. Under similar (competitive) reaction conditions, YC 6H4SHs with Y = H, 4-CN, and 3-CF3 were completely inert; with Y = 4-CH3O, there was some very minor desulfurization, whereas with Y = 4-N(CH3)2 and 4-N(CH3)(H), the sulfur extrusions were as fast as that for Y = 4-NH2. We tentatively suggest that this apparently novel reaction is a chain process initiated by the bimolecular formation of diatomic sulfur, S2, followed by a reversible addition of ground state, triplet 3S2 to the thiol sulfur atom, 4-NH2C 6H4S↑(SS↑)H, and insertion into the S-H bond, 4-NH2C6H4SSSH. In a cascade of reactions, aniline and S8 are formed with the chains being terminated by reaction of 4-NH2C6H4S↑(SS↑)H with 4-NH2C6H4SH. Such a reaction mechanism is consistent with the first-order kinetics. That this reaction is primarily observed with 4-YC6H4SH having Y = N(CH3) 2, N(CH3)(H), and NH2 is attributed to the fact that these compounds can exist as zwitterions.
Mulder, Peter,Mozenson, Olga,Lin, Shuqiong,Ingold
p. 2379 - 2386
(2007/10/03)

Catalytic decomposition of simulants for chemical warfare V agents: Highly efficient catalysis of the methanolysis of phosphonothioate esters
(Chemical Equation Presented) As good as the original: Extremely effective methanolysis of phosphonothioates using metal-containing systems (e.g., 1) was achieved. The catalytic methanolysis of a SCH2CH2NEt 2 derivative, an analogue of the organophosphorus chemical warfare material VX, was predicted, and the catalyzed methanolysis of S-(3,5-dichlorophenyl) O-ethyl methylphosphonothioate was shown to involve a concerted displacement of the aryl thioate (transition state 2)
Melnychuk, Stephanie A.,Neverov, Alexei A.,Brown, R. Stan
p. 1767 - 1770
(2007/10/03)

A mild and practical deprotection method for benzyl thioethers
A highly effective and mild deprotection method was developed for benzyl thioethers using dibutylmagnesium in the presence of a catalytic amount of titanocene dichloride. This methodology is applicable to both aromatic and aliphatic benzyl thioethers.
Akao, Atsushi,Nonoyama, Nobuaki,Yasuda, Nobuyoshi
p. 5337 - 5340
(2007/10/03)

Mechanistic studies of la3+- And Zn2+-catalyzed methanolysis of aryl phosphate and phosphorothioate triesters. Development of artificial phosphotriesterase systems
The methanolyses of a series of O,O-diethyl O-aryl phosphates (2,5) and O,O-diethyl S-aryl phosphorothioates (6) promoted by methoxide and two metal ion systems, (La3+)2(-OCH3)2 and 4:Zn2+:-OCH3 (4 = 1,5,9- triazacyclododecane) has been studied in methanol at 25°C. Bronsted plots of the log k2 values vs. sspKa for the phenol leaving groups give βlg values of -0.70. -1.43 and -1.12 for the methanolysis of the phosphates and -0.63, -0.87 and -0.74 for the methanolysis of the phosphorothioates promoted by the methoxide, La 3+ and Zn2+ systems respectively. The kinetic data for the metal-catalyzed reactions are analyzed in terms of a common mechanism where there is extensive cleavage of the P-XAr bond in the rate-limiting transition state. The relevance of these findings to the mechanism of action of the phosphotriesterase enzyme is discussed. The Royal Society of Chemistry 2005.
Liu, Tony,Neverov, Alexei A.,Tsang, Josephine S.W.,Brown, R. Stan
p. 1525 - 1533
(2007/10/03)

Facile introduction of SH group on aromatic substrates via electrophilic substitution reactions
Herein, we describe a mild and efficient two-step procedure to introduce a thiol group on aromatic substrates. First, reaction with an activated sulfoxide leads to an arylsulfonium salt intermediate. Then, two successive β-elimination-based dealkylation reactions afford the desired arylthiols in good to excellent yields.
Becht, Jean-Michel,Wagner, Alain,Mioskowski, Charles
p. 5758 - 5761
(2007/10/03)

Chemoselective protection of thiols versus alcohols and phenols. The Tosvinyl group
The conjugate addition of aliphatic and aromatic thiols to ethynyl p-tolyl sulphone (tosylacetylene) has been managed to afford Tosvinyl derivatives chemoselectively (in the presence of oxygen nucleophiles) and stereoselectively (isomers Z) in practically quantitative yields. The conditions of choice are: catalytic amounts of Et3N (only 0.5-1.0 mol%), a reaction temperature around 0°C and, for the less acidic thiols, CF3CH2OH or CH3CN/CF3CH2OH as the solvent. Thus, N-Boc-Cys-OMe has been quantitatively protected as its S-Tosvinyl derivative in the presence of N-Boc-Ser-OMe and N-Boc-Tyr-OMe. This novel protecting group is stable to several basic and acidic conditions; its removal is achieved at rt by treatment with an excess of pyrrolidine or at 0°C with alkanethiolate ions.
Arjona, Odón,Medel, Rocío,Rojas, Jenny,Costa, Anna M.,Vilarrasa, Jaume
p. 6369 - 6373
(2007/10/03)

Direct synthesis of thioethers from sulfonyl chlorides and activated alcohols
An efficient, safe one-pot synthesis of thioethers from aromatic sulfonyl chlorides and activated alcohols has been developed under non-aqueous conditions.
Martin, Michael T,Thomas, Alford M,York, Douglas G
p. 2145 - 2147
(2007/10/03)

An efficient synthetic route to aryl thiocyanates from arenesulfinates
An efficient procedure for the conversion ot the inexpensive and readily available arenesulfinate (sodium) salts in three steps into the corresponding aryl thiocyanates is described. Overall yields are high, and the presence of both electron-with drawing and electron-donating substituents is well tolerated.
Still,Watson
p. 1355 - 1359
(2007/10/03)

Organosulfur compounds as pre-exposure therapy for threat agents.
A series of symmetric (Ar-S-S-Ar) and unsymmetric (Ar-S-S-CH2CH2NH3+Cl-) disulfides have been prepared and evaluated as potential cyanoprotective agents. Target compounds have been prepared by known methods and/or methods developed by us specifically for this program, e.g. reaction of a thiol with 2,2'-dithiobis(benzothiazole) (BT-S-S-BT) followed by reaction with a second thiol. Both 4-methoxyphenyl disulfide and 2-aminoethyl-4-methoxyphenyl disulfide hydrochloride are cyanoprotective against 2-LD50 of injected cyanide. Evaluation of both symmetric and unsymmetric related disulfides indicates that structural requirements for cyanoprotective activity are stringent and strongly suggest that protection is enzyme mediated. In addition to cyanoprotective action, initial results suggest that unsymmetric disulfides may evolve into effective antimustard agents.
Ternay Jr.,Brzezinska,Sorokin,Cook,Lyaschenko
p. S31-34
(2007/10/03)

Rhodium-Catalyzed Rearrangement of α-Diazo Thiol Esters to Thio-Substituted Ketenes. Application in the Synthesis of Cyclobutanones, Cyclobutenones, and β-Lactams
Exposure of α-diazo thiol esters (1) to the action of catalytic rhodium(II) acetate leads to a remarkably facile "thia-Wolff rearrangement", producing thio-substituted ketenes which combine with a variety of ketenophiles to provide access to α-thiocyclobutanones, cyclobutenones, and β-lactams. Reductive desulfurization of these cycloadducts takes place under mild conditions and in excellent yield, and this sequence thus represents a useful new alternative to the existing dichloroketene-based methodology for the synthesis of four-membered carbocycles and heterocycles.
Lawlor, Michael D.,Lee, Thomas W.,Danheiser, Rick L.
p. 4375 - 4384
(2007/10/03)

Structure-Reactivity Correlations in the Aminolysis of Ethyl S-Aryl Thiolcarbonates
The reactions of secondary alicyclic amines (saa) with ethyl S-4-X-phenyl thiolcarbonates (X = Cl, H, Me, and MeO) are subjected to a kinetic analysis in water, 25.0°C, ionic strength 0.2 (KCl). By following the leaving groups spectrophotometrically (260-270 nm), under amine excess, pseudo-first-order rate coefficients (kobsd) are obtained. Plots of kobsd against free-amine concentration at constant pH are linear, with slope (kN) independent of pH. The Broensted-type plots (log kN against amine pKa) are linear for the aminolysis of the four substrates, with slopes βN = 0.7-0.8. The magnitudes of the slopes are consistent with a stepwise mechanism through a zwitterionic tetrahedral intermediate (T±) whose breakdown to products is rate-determining (k2 step). This mechanism is simpler than that for the same aminolysis of the corresponding ethyl S-aryl dithiocarbonates, which includes proton transfer from T± to the amine (k3 step), due to the fact that for the title reactions k2 > k3[amine]. With the results of the present work and those for the reactions of saa with ethyl S-4-nitrophenyl thiolcarbonate, a dual parametric equation is deduced for kN as a function of amine and leaving group basicity, with both βN and βlg = 0.8. Another dual parametric equation is deduced from literature data for the pyridinolysis of ethyl S-aryl thiolcarbonates. Comparison of both multiparametric expressions shows that pyridines are more reactive than isobasic saa toward thiolcarbonates when breakdown of T± to products is rate-limiting.
Castro, Enrique A.,Cubillos, Maria,Santos, Jose G.
p. 6342 - 6346
(2007/10/03)

Oxidative cleavage of S-Arylmercaptoacetic acids by pyridinium chlorochromate: Kinetic and correlation analysis
Kinetics of oxidation of 24 S-Arylmercaptoacetic acids (SAMA) by pyridinium chlorochromate (PCC) have been studied in acid medium. The product of oxidation is the corresponding thiophenol. The rate data of meta- and para-substituted acids have been correlated well with σI, σ°R values and the meta-compounds correlate well with F,R values. The reaction constants are negative and of smaller magnitudes. Further, the ortho-substituted acids show a good correlation with triparametric equation involving Taft's σI and σ°R and charton's steric parameter v. There is no considerable steric contribution to the total orthosubstituent effect. Based on these observations, the mechanism involving the formation of protonated arylsulfinylacetic acid intermediate, followed by an intramolecular rearrangement leading to the product thiophenol has been proposed.
Kabilan,Girija,Rajagopal
p. 683 - 688
(2007/10/03)

p-Toluenesulfonylacetylene as thiol protecting group
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Arjona, Odon,Iradier, Fatima,Medel, Rocio,Plumet, Joaquin
p. 6090 - 6093
(2007/10/03)

Phenylthio-derivatives of α-methylene-γ-lactones as pro-drugs of cytotoxic agents
A series of substituted phenylthio-derivatives of grosheimin (1), a natural cytotoxic guaianolide, were investigated with the aim of providing insight into their mechanism of action as cytotoxic agents against KB cell lines. Hydrolysis data, kinetics, in the presence and in the absence of H2O2, and the valuation of lipophilicity were correlated with cytotoxicity values and with Hammett-σ-values of substituents (R) at the thiophenol ring. These compounds behave as 'pro-drugs' which release the cytotoxic agent grosheimin by sulphur-oxidation promoted by H2O2 and subsequent retro- elimination which depends on the nature and position of the R substituent.
Fardella, Giuseppe,Barbetti, Paolo,Grandolini, Giuliano,Chiappini, Ione,Ambrogi, Valeria,Scarcia, Vito,Furlani Candiani, Ariella
p. 515 - 523
(2007/10/03)

Non-aqueous reduction of aromatic sulfonyl chlorides to thiols using a dichlorodimethylsilane-zinc-dimethylacetamide system
A new and efficient method for the non-aqueous reduction of sulfonyl chlorides to affored the corresponding thiols by use of a dichlorodimethylsilane-zinc-dimethylacetamide system was successfully developed. Various aromatic thiols were prepared in high yield by easy operation. Continuous reactions with the above reduction using the prepared thiol were also demonstrated.
Uchiro, Hiromi,Kobayashi, Susumu
p. 3179 - 3182
(2007/10/03)

Structure - reactivity correlation in the reactions of pyrrolidine with O-ethyl S-aryl dithiocarbonates in aqueous ethanol
The reactions of pyrrolidine with O-ethyl S-(X-phenyl) dithiocarbonates (X = 4-methyl, 4-methoxy, H, 4-chloro, 4-nitro, 2,4-dinitro, and 2,4,6-trinitro) are subjected to a kinetic study in 44 wt% aqueous ethanol, 25.0°C, and ionic strength 0.2 M (maintained with KCl). Pseudo-first-order kinetics are found under amine excess. Linear plots of the pseudo-first-order rate coefficient against concentration of free-base pyrrolidine are obtained for all the reactions, nucleophilic rate coefficient (kN) being the slope of such plots. The Bronsted-type plot (log kN vs. pKa for the leaving group) is linear with slope β1g = -0.2, which is consistent with a mechanism through a tetrahedral intermediate (T±) where its formation is rate determining. The β1g value is very similar to that found in the same reactions in water. There is a great difference in the mechanism of the reactions of O-ethyl S-phenyl dithiocarbonate with pyrrolidine (order one in amine) and piperidine (complex order in amine) in aqueous ethanol, and this is attributed to a greater nucleofugality from T± of piperidine rather than pyrrolidine.
Castro,Cabrera,Santos
p. 113 - 117
(2007/10/03)

Oxidative Cleavage of S-Arylmercaptoacetic Acids by Sodium Perborate: Kinetic and Correlation Study
Kinetics of oxidation of twenty six S-arylmercaptoacetic acids (SAMA) (I) by sodium perborate (PB) have been studied in acid medium.The product of oxidation is the corresponding thiophenol.The rate data of meta- and para-substituted acids have been correlated with DSP equations.While the para-compounds correlate well with ?I and ?0R values, the meta-compounds correlate well with ?I and ?-R values.The reaction constants are negative and of smaller magnitudes.Further, the ortho-substituted acids show a good correlation with a triparametric equation involving Taft's ?I and ?0R and Charton's steric parameter ν.There is a considerable steric contribution to the total ortho-substituent effect.Based on these observations, mechanism involving the formation of protonated arylsulfinylacetic acid intermediate, followed by an intramolecular rearrangement leading to the product thiophenol has been proposed.
Kabilan, S.,Pandiarajan, K.,Krishnasamy, K.,Sankar, P.
p. 443 - 452
(2007/10/02)

Catalytic kinetic resolution of 5-alkoxy-2(5H)-furanones
The kinetic resolution of racemic 5-alkoxy-2(5H)-furanones, using a chiral aminoalcohol catalyzed 1,4-addition of arylthiols, was examined. Using various butenolides it was shown that a γ-alkoxy substituent appears to be essential to reach high enantioselectivities whereas electron-donating substituents in the arylthiols also increase the selectivity. Cinchona alkaloids are the preferred catalysts for the kinetic resolution, with quinine and quinidine leading to the most efficient and selective thiol additions. A remarkable dilution effect and a strong dependency on the mode of addition of reactants were observed. Optimization studies are presented of the kinetic resolution of 5-methoxy-2(5H)-furanone 2 resulting in (R)-2 or (S)-2 with enantiomeric excesses exceeding 90%. A mechanism for the quinine (quinidine) catalyzed kinetic resolution is given.
Faber, Wijnand S.,Kok, Johan,De Lange, Ben,Feringa, Ben L.
p. 4775 - 4794
(2007/10/02)

Structure-Reactivity Relationships in the Aminolysis of O-Ethyl S-Aryl Dithiocarbonates in Aqueous Solution
The reactions of O-ethyl S-(X-phenyl) diothiocarbonates (X = p-Cl, p-Me, and p-MeO) with a series of secondary alicyclic amines and those of the same substrates and analogous derivatives (X = H, p-NO2, 2,4-(NO2)2 with pyrrolidine are subjected to a kinetic study in water, 25.0 deg C, ionic strength 0.2 M (KCl).The reactions of piperidine and pyrrolidine show second-order kinetics (first order in amine) with the formation of a zwitterionic tetrahedral intermediate (T+/-) as the rate-determining step.The reactions of the other amines exhibit orders in amine differentfrom one, compatible with the presence of an anionic intermediate (T-), resulting from a kinetically important proton transfer from T+/- to the amine.The rate of this proton transfer is faster than that of expulsion of arylthiolate from T+/- (k2) as evidenced by the estimation of these rate coefficients.The rate constants for formation of T+/- (k1) are obtained experimentally, and those for amine expulsion from T+/- (k-1) are estimated.Equations for k1 and k-1 are derived as functions of the basicity of the amine and leaving (aryl thiolate) groups.Comparison of the k-1 and k2 values found in the present reactions with those obtained in the aminolysis of aryl dithioacetates shows that substitution of Me by EtO as the "acyl" group of the zwitterionic tetrahedral intermediate destabilizes this species.
Castro, Enrique A.,Cubillos, Maria,Ibanez, Fernando,Moraga, Inge,Santos, Jose G.
p. 5400 - 5404
(2007/10/02)

Kinetics and Mechanism of the Acid-Catalysed Hydrolysis of Benzaldehyde Diaryl Thioacetals and of Benzaldehyde S-Aryl, S-Ethyl Acetals in Aqueous Perchloric Acid
The effects on the rate of hydrolysis of changes in aryl substituents, acid concentration, temperature, and solvent isotope, show that the acid-catalysed hydrolyses of five benzaldehyde diaryl thioacetals and three benzaldehyde S-aryl, S-ethyl acetals in 2-7 mol dm-3 aqueous perchloric acid proceed via essentially A1 mechanisms.The pattern of the substituent effects found for the leaving, and remaining, S-aryl groups is similar to that found previously for leaving and remaining groups in O,O- and O,S-acetals.
Ali, Muhammad,Satchell, Derek P. N.
p. 1825 - 1828
(2007/10/02)

Achiral fluorine-containing liquid crystals
Achiral fluorine-containing liquid crystal compounds are provided. The compounds comprise a fluorocarbon terminal portion and a hydrocarbon or another fluorocarbon terminal portion, the terminal portions being connected by a central core, the compounds having smectic mesophases or having latent smectic mesophases. The compounds are useful in liquid crystal display devices both along and in mixtures with other materials. Also provided is a process for preparing these compounds.
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(2008/06/13)

Rapid and Selective Reduction of Functionalized Aromatic Disulfides with Lithium Tri-tert-butoxyaluminohydride. A Remarkable Steric and Electronic Control. Comparison of Various Hydride Reagents
Lithium tri-tert-butoxyaluminohydride (LTBA), an exceptionally mild reducing agent in organic synthesis, reduces functionalized aromatic disulfides to the corresponding thiols in quantitative yield.The reaction is rapid (for example, o-tolyl disulfide is reduced to completion in 60 min at 25 deg C) and can tolerate a wide variety of functional groups, such as halogen, nitro, carboxylic acid, and their derivatives.The presence of electron-withdrawing substituents dramatically enhances the rate of reduction (p-chlorophenyl disulfide is quantitatively reduced in 30 s) and electron-releasing substituents diminishes the rate of cleavage.The reaction is sensitive to steric effects (2,4-di-tert-pentylphenyl disulfide underwent 25percent reduction in 24 h).However, such hindered disulfides can be rapidly and quantitatively reduced in refluxing THF.The reaction of LTBA with alkyl disulfides is extremely sluggish.The reaction provides a useful and simple means for the facile and selective reduction of aromatic disulfides where this is required in synthetic operations.
Krishnamurthy, S.,Aimino, D.
p. 4458 - 4462
(2007/10/02)

LIGAND-COUPLING THROUGH ?-SULFURANE FORMED ON TREATMENT OF SULFILIMINES WITH HYDRIDE
The reaction of N-(4-tosyl)sulfilimines with lithium aluminum hydride was found to proceed via the ligand-coupling within the ?-sulfurane formed as an intermediate by giving the corresponding sulfides in excellent yields under mild conditions.
Kim, Kyoung Soo,Jung, In Bae,Kim, Yong Hae,Oae, Shigeru
p. 1087 - 1090
(2007/10/02)

THE REACTION BETWEEN ARENEDIAZONIUM TETRAFLUOROBORATES AND ALKALINE THICARBOXYLATES IN DMSO: A CONVENIENT ACCESS TO ARYL THIOLESTERS AND OTHER AROMATIC SULFUR DERIVATIVES.
The reaction between potassium thioacetate or sodium thiobenzoate and arenediazonium tetrafluoroborates in DMSO leads to the corresponding aryl thiolesters 1 which can either be isolated or further reacted providing a convenient one-pot access to a number of other aromatic sulfur derivatives.
Petrillo, Giovanni,Novi, Marino,Garbarino, Giacomo,Filiberti, Marcos
p. 7411 - 7420
(2007/10/02)

S-Aryl(tetramethyl)isothiouronium salts as potential antimicrobial agents, II
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Tait,Parenti,Di Bella,Bondi,Quaglio
p. 203 - 210
(2007/10/02)

Reactions of Sodium Borohydride. IV. Reduction of Aromatic Sulfonyl Chlorides with Sodium Borohydride
Aromatic sulfonyl chlorides were reduced with sodium borohydride in tetrahydrofuran at 0 deg C to the corresponding sulfinic acids in good yields.Further reduction proceeded when the reaction was carried out under reflux in tetrahydrofuran to give disulfide and thiophenol derivatives via sulfinic acid.Furthermore, sulfonamides were reduced with sodium borohydride by heating directly to give sulfide, disulfide and thiophenol derivatives, and diphenyl sulfone was reduced under similar conditions to give thiophenol and biphenyl.Keywords---reduction; sodium borohydride;aromatic sulfonyl chloride; sulfonamide; sulfone; aromatic sulfinic acid disulfide; sulfide; thiophenol
Nose, Atsuko,Kudo, Tadahiro
p. 1770 - 1776
(2007/10/02)

New Birch Type Reduction. Halogen or Halides-Activated Reduction of Disulfides to Thiols with Aluminium in Liquid Ammonia
Aromatic and aliphatic disulfides were reduced to the corresponding thiols in high yields by new halogen or halides-activated Birch type reduction with aluminium in liquid ammonia.
Sato, Ryu,Akaishi, Ryouichi,Goto, Takehiko,Saito, Minoru
p. 773 - 774
(2007/10/02)

Kinetic Study of Substituent Effects on the Mechanism of β-Elimination of Arenethiol from trans-2,3-Bis-(arylthio)-4-nitro-2,3-dihydrothiophenes in Toluene
The 2,3-dihydrothiophene derivatives (1b-f) readily undergo, in toluene, regiospecific tributylamine-promoted syn-elimination of arenethiol to give the 2-(arylthio)-4-nitrothiophenes (2b-f).For the rather complex kinetic behaviour displayed by each member of the series, a rationalisation is proposed based on a stability of the substrate's conjugate base sufficient to allow formation of non-negligible concentrations of an intermediate ion pair along the reaction co-ordinate.The system allows direct conclusions to be drawn concerning the leaving-group expulsion step: an advanced extent of bond cleavage between carbon and the leaving group can be postulated in the transition state.
Petrillo, Giovanni,Novi, Marino,Garbarino, Giacomo,Dell'Erba, Carlo
p. 1741 - 1746
(2007/10/02)

SYNTHESIS OF AROMATIC THIOLS FROM ARYL IODIDES AND THIOUREA BY MEANS OF NICKEL CATALYST
Nickel(0) complex, generated in situ from bis(triethylphosphine)nickel(II) chloride and sodium cyanoborohydride, catalyzed the nucleophilic displacement of aryl iodides with thiourea.S-Aryl-isothiuronium salts or aromatic thiols were obtained in good yields after simple work-up procedures.
Takagi, Kentaro
p. 1307 - 1308
(2007/10/02)

Cathodic Cleavage of Some Aryl Phenacyl Sulfides
The electrolytic reduction of some aryl phenacyl sulfides in aqueous ethanol and anhydrous acetonitrile solutions has been investigated by means of polarography and controlled potential electrolysis.Dc polarograms of these compounds exhibit two waves in all solutions studied, the first of which corresponds to a one-electron and two-electron transfer depending upon the absence and presence of proton donor.The electrode reaction taking place at the first reduction step involves cleavage of the carbon-sulfur bond, resulting in formation of acetophenone and the corresponding thiols in good yields even in acetonitrile solution containing no proton donor.The second reduction step corresponds to the reduction of the acetophenone produced.
Kunugi, Akira,Muto, Akinori,Hirai, Taketsugu
p. 1262 - 1266
(2007/10/02)

Reductive Cleavage of Aromatic Disulfides Using a Polymer-Supported Phosphine Reagent
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Amos, Richard A.,Fawcett, Shayne M.
p. 2637 - 2639
(2007/10/02)

Simple Syntheses of Aryl Alkyl Thioethers and of Aromatic Thiols from Unactivated Aryl Halides and Efficient Methods for Selective Dealkylation of Aryl Alkyl Ethers and Thioethers
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Testaferri, L.,Tiecco, M.,Tingoli, M.,Chianelli, D.,Montanucci, M.
p. 751 - 755
(2007/10/02)

SYNTHESIS AND CONFIGURATIONAL STUDIES OF ARYL CYCLOPROPYL SULFONES
The cycloaddition of arylthiocarbenes to styrene gave stereospecifically cis-1-(arylthio)-2-phenylcyclopropanes, which were subsequently oxidized to the corresponding sulfones.The cyclopropanation of α,β-unsaturated sulfones with dimethylsulfonium methylide yielded stereoselectively trans-1-(arylsulfonyl)-2-arylcyclopropanes.The configurational assignments of these compounds have been arrived at on the basis of IR and PMR spectral data.Chemical shifts for ring protons and other substituents reveal that all the substituents tend to cause protons cis to them to appear at higher fields than those trans to them.This has been used as a criterion to distinguish between cis and trans aryl cyclopropyl sulfones.
Reddy, D. Bhaskar,Balaji, T.,Reddy, B. Venkataramana
p. 297 - 306
(2007/10/02)

Elimination-Addition Reactions of 3-sydnones. Displacement of the Sulfide by an Ether Group
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Pirl, Joerg N.,Bell, Charles L.,Bauer, Ludwig
p. 3971 - 3974
(2007/10/02)

ANTIMONY-SULPHUR BONDED COMPOUNDS. IV. FURTHER STUDIES ON THE THERMAL DECOMPOSITION OF TETRA-ORGANOANTIMONY MERCAPTIDES
The thermolytic decompositions of Ph4SbSAr in organic solvents are reported.Solvent-derived products from decompositions in CCl4 and cyclohexane confirm the free radical nature of the reactions.Thermal decompositions of Ph3(p-MeC6H4)SbSC6H4OMe-p, or Ph(p-
Bedi, Bhupinder S.,Grant, Douglas W.,Tewnion, Lesley,Wardell, James L.
p. 251 - 266
(2007/10/02)