- Solvent-free acetylation of thiols under catalysis of MgBr 2·OEt2
-
Solvent-free protection of aromatic and aliphatic thiols with acetic anhydride was performed at room temperature under trace quantities of magnesium bromide ethyl etherate, affording rapid formation of various thiol esters in excellent yields. Copyright Taylor & Francis Group, LLC.
- Mojtahedi, Mohammad M.,Abaee, M. Saeed,Javadpour, Mashal
-
-
Read Online
- Methanesulfonic anhydride-promoted sustainable synthesis of thioesters from feedstock acids and thiols
-
Abstract: An unprecedented metal-, halogen- and solvent-free, MSAA-promoted S-carbonylation of thiols with feedstock acids has been developed. This new transformation provides an efficient and atom-economic strategy for the synthesis of thioesters in a single operation from readily available and inexpensive starting materials. The reaction avoids the use of expensive and hazardous coupling reagents, bases and generates water as the only by-product, thus making this chemical synthetic process more viable, environment-friendly and contributing towards sustainable chemistry. Graphic abstract: [Figure not available: see fulltext.].
- Singh, Pallavi,Peddinti, Rama Krishna
-
-
- Magnetically recyclable silica-coated ferrite magnetite-K10montmorillonite nanocatalyst and its applications in O, N, and S-acylation reaction under solvent-free conditions
-
Novel silica-coated ferrite nanoparticles supported with montmorillonite (K10) have been prepared successfully by using a simple impregnation method. Further, these nanoparticles were characterized by using different analytical methods like FT-IR, PXRD, EDS, and FE-SEM techniques. In addition, these nanoparticles have been explored for their catalytic activity for the O, N, and S-acylation reactions under solvent-free conditions which gave moderate to excellent yields in a much shorter reaction time. Moreover, these nanoparticles could easily be separated out from the reaction medium after the reaction completion by using an external magnetic field and have been re-used for 10 cycles without any significant loss of the catalytic activity.
- Kumar, Pushpendra,Patil, Shripad M.,Tandon, Nitin,Tandon, Runjhun
-
p. 21291 - 21300
(2021/07/01)
-
- Air-stable binuclear Titanium(IV) salophen perfluorobutanesulfonate with zinc power catalytic system and its application to C–S and C–Se bond formation
-
An air-stable μ-oxo-bridged binuclear Lewis acid of titanium(IV) salophen perfluorobutanesulfonate [{Ti(salophen)H2O}2O][OSO2C4F9]2 (1) was successfully synthesized by the reaction of TiIV(salophen)Cl2 with AgOSO2C4F9 and characterized by techniques such as IR, NMR and HRMS. This complex was stable open to air over a year, and exhibited good thermal stability and high solubility in polar organic solvents. The complex also had relatively strong acidity with a strength of 0.8 Ho ≤ 3.3, and showed high catalytic efficiency towards various C–S and C–Se bond formations in the presence of zinc power. This catalytic system affords a mild and efficient approach to synthesis of thio- and selenoesters, α-arylthio- and seleno-carbonyl compounds, and thio- and selenoethers.
- Wang, Lingxiao,Qiao, Jie,Wei, Jiancong,Liang, Zhiwu,Xu, Xinhua,Li, Ningbo
-
-
- Air-Tolerant Direct Thiol Esterification with Carboxylic Acids Using Hydrosilane via Simple Inorganic Base Catalysis
-
Direct thioesterification of carboxylic acids with thiols using nontoxic activation agents is highly desirable. Herein, an efficient and practical protocol using safe and inexpensive industrial waste polymethylhydrosiloxane as the activation agent and K3PO4 with 18-crown-6 as a catalyst is described. Various functional groups on carboxylic acid and thiol substituents can be tolerated by the present system to afford thioesters in yields of 19-100%.
- Xuan, Maojie,Lu, Chunlei,Liu, Meina,Lin, Bo-Lin
-
p. 7694 - 7701
(2019/06/27)
-
- Fungicidal Activity of S-Esters of Thiocarboxylic Acids as Antimicrobial Additives to Petroleum Products
-
Abstract: A variety of aliphatic and aromatic S-esters of thiocarboxylic acids have been tested for antimicrobial activity. The relationship between the chemical structure of the compounds R1SC(O)R2 and their toxicity for microorganisms has been revealed, and the effect of various functional groups on the antimicrobial properties has been shown. The cooling lubricant IKhP-45E with S-aryl thioacetate additives has been tested. It has been shown that the additives used (0.25–0.5 wt %) inhibit the growth of all the studied microorganisms; however, their activity with respect to fungi is higher. The introduction of S-aryl thioacetates provides the resistance of these oils to microbiological deterioration to retain the physicochemical properties for a long period of time.
- Aliev,Belovezhets,Oparina
-
-
- Manganese-mediated acetylation of alcohols, phenols, thiols, and amines utilizing acetic anhydride
-
Manganese(II) chloride-catalyzed acetylation of alcohols, phenols thiols and amines with acetic anhydride is reported. This method is environment-friendly and economically viable as it involves inexpensive, relatively benign catalyst, mild reaction condition, and simple workup. Acetylation is performed under the solvent-free condition at ambient temperature and acetylated products obtained in good to excellent yields. Primary, secondary heterocyclic amines, and phenols with various functional groups are smoothly acetylated in good yields. This method exhibits exquisite chemoselectivity, the amino group is preferentially acetylated in the presence of a hydroxyl/thiol group.
- Jain, Isha,Sharma, Ramandeep,Malik, Payal
-
supporting information
p. 2952 - 2960
(2019/09/13)
-
- Thioesters as Bifunctional Reagents for 2-Naphthylamine Sulfuracylation
-
An efficient and convenient strategy for the preparation of diaryl sulfides via a Fe-promoted direct sulfuracylation of 2-naphthylamine using thioesters as bifunctional reagents is described. This synthetic strategy features high chemoselectivity, good substrate scope and functional group tolerance. (Figure presented.).
- Xiao, Fuhong,Yuan, Shanshan,Wang, Dahan,Liu, Saiwen,Huang, Huawen,Deng, Guo-Jun
-
supporting information
p. 3331 - 3336
(2019/06/13)
-
- S-Acetylation of Thiols Mediated by Triflic Acid: A Novel Route to Thioesters
-
This paper demonstrates an efficient, mild, and chemoselective synthesis of various thioesters via a HOTf-catalyzed S-acetylation of aromatic and aliphatic thiols using isopropenyl acetate as a cheap and convenient acetylating agent. During our tests, we also investigated the differences between the activities of metal triflates and triflic acid as catalysts in the acetylation of thiols. Finally, the potential of our concept has been increased by the implementation of Nafion as a heterogeneous catalyst for S-acetylation of thiols.
- Kuciński, Krzysztof,Hreczycho, Grzegorz
-
p. 489 - 493
(2018/04/27)
-
- Preparation method and application of novel ionic binuclear Schiff base titanium complex
-
The invention provides a preparation method of a novel ionic binuclear Schiff base titanium complex and a synthetic method of applying the novel ionic binuclear Schiff base titanium complex to catalyze zinc powder and reduce disulfide or selenide to prepare sulfo(seleno) ester and dissymmetric sulfoether(selenide). The complex is a cationic binuclear Schiff base titanium complex, wherein titaniumatoms are bridged by oxygen atoms and are coordinated with a Schiff base ligand and a hydrone, and an ionic bond is formed by a cation part and an anion part of whole Schiff base titanium. The ionic binuclear Schiff base titanium complex is used as a catalyst, the zinc powder is used as a reducer, the disulfide(selenide) can be reduced and fractured, and the disulfide(selenide) can further and respectively react with anhydride, an alpha-bromo carbonyl compound and bromoalkane to prepare the sulfo(seleno) ester and the dissymmetric sulfoether(selenide). According to the preparation method provided by the invention, the defects that traditional lewis acid halide is deliquescent, an absolute solvent is used, conditions are strict and the like are overcome; an effective path for reducing the disulfide or selenide to prepare the sulfo(seleno) ester and the dissymmetric sulfoether(selenide) is provided, and the preparation method has the advantages of high yield, simpleness in operation andthe like.
- -
-
Paragraph 0042; 0043
(2018/04/03)
-
- Harnessing the catalytic behaviour of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP): An expeditious synthesis of thioesters
-
A novel, efficient, metal-, base- and acid-free straightforward protocol has been developed for the construction of useful thioesters. The immense catalytic potential of HFIP for promoting the thiocarbonylation of acyl halides and thiols is disclosed. HFIP was recovered with ease and reused for further reactions without any loss of reactivity. Both aryl and alkyl thiols bearing electron-donating and electron-withdrawing groups as well as aryl- and alkyl acyl halides worked well in this reaction. Inexpensive precursors, short reaction time, obviating workup, high atom economy, and gram-scale preparation are the significant features of the developed eco-friendly route for S-carbonylation of thiols.
- Singh, Pallavi,Peddinti, Rama Krishna
-
supporting information
p. 1875 - 1878
(2017/04/21)
-
- Diazepinium perchlorate: a neutral catalyst for mild, solvent-free acetylation of carbohydrates and other substances
-
Diazepinium perchlorate, an essentially neutral organic salt possessing excellent stability, has been found to be well suited for the acetylation of free as well as partially protected sugars, phenols, thiophenols, thiols and other alcohols as well as amines. The diazepinium perchlorate-catalyzed acetylation is mild, organic and solvent-free and leaves acid sensitive protecting groups such as TBDMS/TBDPS/Tr ethers and isopropylidene/benzylidene acetals present on a substrate unaffected. Regioselective hydroxyl protection in partially protected carbohydrate derivatives/polyhydroxylic compounds was possible and was proved to be a convenient time-saving alternative to the conventional synthesis of such compounds. Easy preparation of the catalyst, mild reaction conditions and an environmentally benign protocol are some of the notable features of this reaction. The results obtained on the acetylation of phenols and thiophenols could be rationalized through their local nucleophilicity index obtained from DFT calculations.
- Giri, Santosh Kumar,Gour, Rajesh,Kartha, K. P. Ravindranathan
-
p. 13653 - 13667
(2017/03/11)
-
- Highly efficient and recyclable acetylation of phenols and alcohols by nickel zirconium phosphate under solvent-free conditions
-
Nickel zirconium phosphate nanoparticles have been used as an efficient catalyst for the acetylation of a wide range of alcohols and phenols with acetic anhydride in good to excellent yields under solvent-free conditions. The steric and electronic properties of the different substrates had a significant influence on the reaction conditions required to achieve the acetylation. The catalyst used in the current study was characterized by inductively coupled plasma optical emission spectroscopy, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity.
- Hajipour, Abdol Reza,Karimi, Hirbod,Kohi, Afshin
-
-
- A new ferrocene-based bulky pyridine as an efficient reusable homogeneous catalyst
-
An effective approach to reusing a homogeneous catalyst has been demonstrated. A ferrocene-based bulky pyridine has been synthesized and utilized as a homogeneous catalyst for the synthesis of benzoylfumarates as well as for acetylation. After the reaction, the catalyst was separated by simple precipitation and reused without appreciable loss of activity. The Royal Society of Chemistry 2013.
- Kashyap, Bishwapran,Phukan, Prodeep
-
p. 15327 - 15336
(2013/09/02)
-
- Silver triflate catalyzed acetylation of alcohols, thiols, phenols, and amines
-
A variety of alcohols, thiols, phenols, and amines were subjected to acetylation reaction using acetic anhydride in the presence of catalytic quantity of silver triflate. The method described has a wide range of applications, proceeds under mild conditions, does not involve cumbersome workup, and the resulting products are obtained in high yields within a reasonable time. Georg Thieme Verlag Stuttgart · New York.
- Das, Rima,Chakraborty, Debashis
-
experimental part
p. 1621 - 1625
(2011/06/25)
-
- Rapid and convenient synthesis of S-acetylarenethiols by non-aqueous diazotization
-
A series of S-acetylarenethiols were synthesized from aromatic amines by a rapid, convenient and efficient method. Arenediazonium tetrafluoroborates were afforded from aromatic amines, isoamyl nitrite and boron trifluoride etherate in non-aqueous diazotization system, then reacted with potassium thioacetate in dimethylsulfoxide to obtain desired products in moderate to good yields and short reaction times. The product S-acetyl-4-iodothiophenol was characterized by single crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/C with unit cell parameters: a = 0.594 20(12) nm, b = 0.542 00(11) nm, c = 2.9618(6) nm, α = 90.00°, β = 94.23(3)°, γ = 90.00°, Dx = 1.942 g/cm3, Z = 4, F(000) = 528, μ = 3.528 mm-1, R = 0.039 2, wR = 0.099 3, P = (Fo2 + 2Fc2)/3, S = 1.077, (Δρ)max = 0.692 x 1030 e/m3, (Δρ)min = -0.558 x 1030 e/m3. The X-ray crystallographic structure (CCDC-684683) clearly shows that the para atoms I and S lie in the benzene ring plane and no hydrogen bonds were observed.
- Liu, Rui,Li, Yu-Hao,Chang, Jin,Xiao, Qi,Zhu, Hong-Jun
-
experimental part
p. 3059 - 3064
(2010/11/04)
-
- A new odorless one-pot synthesis of thioesters and selenoesters promoted by Rongalite
-
Rongalite promotes cleavage of diaryl disulfides generating chalcogenolate anions that then undergo facile acylation with anhydrides in the presence of CsF to afford thioesters (3) with good to excellent yields. By using the present protocol, 5-arylthio-5-oxopentanoic acid (4) can be facilely prepared. The important features of the methodology are broad substrate scope, simple operation, and no requirement for metal catalysts. It is noteworthy that acylations of diphenyl diselane with anhydrides are also conducted smoothly to afford selenoesters (5) in good yields under the standard conditions.
- Dan, Weixing,Deng, Hongjuan,Chen, Jiuxi,Liu, Miaochang,Ding, Jinchang,Wu, Huayue
-
experimental part
p. 7384 - 7388
(2010/10/02)
-
- Air-stable, cationic, Lewis acid, titanocene perfluorooctanesulfonate- catalyzed reductive cleavage of S-S bond by zinc and its application in synthesis of thioesters
-
Titanocene perfluorooctanesulfonate is air-stable complex. In the presence of 10mol% of the complex, reductive cleavage of an S-S bond by zinc in commercial tetrahydrofuran at room temperature led to nucleophilic sulfur anion species, which reacted with acid anhydrides to afford thioesters in good to excellent yields. Copyright
- Qiu, Ren Hua,Xu, Xin Hua,Li, Yin Hui,Shao, Ling Ling,Zhang, Guo Ping,An, De Lie
-
experimental part
p. 3309 - 3314
(2010/12/24)
-
- Ruthenium(III) chloride catalyzed acylation of alcohols, phenols, and thiols in room temperature Ionic liquids
-
Ruthenium(III) chloride-catalyzed acylation of a variety of alcohols, phenols, and thiols was achieved in high yields under mild conditions (room temperature) in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]). The ionic liquid and ruthenium catalyst can be recycled at least 10 times. Our system not only solves the basic problem of ruthenium catalyst reuse, but also avoids the use of volatile acetonitrile as solvent.
- Xi, Zhiwen,Hao, Wenyan,Wang, Pingping,Cai, Mingzhong
-
experimental part
p. 3528 - 3537
(2009/12/24)
-
- Thallium(III) chloride: A mild and efficient catalyst for acylation of alcohols, phenols and thiols, and for geminal diacylation of aldehydes under solvent-free conditions
-
Thallium(III) chloride is a simple and efficient catalyst for acylation of alcohols, phenols and thiols. It is also very effective for geminal diacylation of aldehydes. The acylation reaction using acetic anhydride proceeds in excellent yield in the presence of catalytic amounts of thallium(III) chloride (1 mol%) at room temperature within relatively short reaction times (20 min). Structurally diverse alcohols, phenols, thiols and aldehydes undergo acylation under solvent-free conditions.
- Kadam, Santosh T.,Kim, Sung Soo
-
experimental part
p. 3307 - 3313
(2009/05/07)
-
- Additive-free chemoselective acylation of amines and thiols
-
Amines with different stereoelectronic nature were efficiently acylated at room temperature using acetic anhydride in the presence of no solvent or additive. Various thiols also react equally well under the same conditions. Chemoselective protection of amines in the presence of thiols, alcohols, and phenols and of thiols in the presence of alcohols, and phenols were achieved using competitive experiments.
- Mojtahedi, Mohammad M.,Saeed Abaee,Heravi, Majid M.,Behbahani, Farahnaz K.
-
-
- KF/Al2O3 catalysed synthesis of thiol esters from N-acylphthalimides and thiols
-
A new method for the preparation of thiol esters from N-acylphthalimides and thiols in the presence of KF/Al2O3 is introduced.
- Movassagh, Barahman,Zakinezhad, Yousef
-
p. 369 - 370
(2007/10/03)
-
- Effect of modification of the electrophilic center on the α effect
-
We report on a nucleophilic study of esters R-C(=X)-Y-Ar in which the electrophilic center has been modified by replacing O by S in the leaving group or carbonyl center: 4-nitrophenyl acetate (1), S-4-nitrophenyl thioacetate (2), 4-nitrophenyl benzoate (3), and O-4-nitrophenyl thionobenzoate (4). The studies include O- and S- nucleophiles as well as α nucleophiles in H2O at 25.0 ± 0.1°C. The sulfur nucleophile (4-chlorothiophenoxide, 4-ClPhS-) exhibits significant enhanced reactivity for the reactions with thiol and thione esters 2 and 4 compared with their oxygen analogues 1 and 3. On the contrary, the common nucleophile OH- is much less reactive towards 2 and 4 compared with 1 and 3. The effect of changing both the electrophilic center and the nucleofugic center on the reactivity of the other oxygen nucleophiles is not so significant: 4-chlorophenoxide (4-ClPhO-) is four to six times more reactive in the reactions with thiol and thione esters 2 and 4 compared with their oxygen analogues 1 and 3. The α effects exhibited by butan-2,3-dione monoximate (Ox-) and HOO- are strongly dependent on the nature of the electrophilic center of the substrates, indicating that the difference in the ground-state solvation energy cannot be fully responsible for the α effect. Our results clearly emphasize the strong dependence of the α effect on the substrate structure, notably, the nature of the electrophilic center. The impact of change in the nucleofuge (1-→2) and the electrophilic center (3-→4) on reactivity indicates that anucleophiles will need to be "purpose built" for decontamination and nucleophilic degradation of specific biocides.
- Um, Ik-Hwan,Lee, Ji-Youn,Bae, Sun-Young,Buncel, Erwin
-
p. 1365 - 1371
(2007/10/03)
-
- CeCl3/Sm induced reductive cleavage of the S-S bond in disulfide: A novel method for the synthesis of β-thioesters, thiol-esters and alkylphenyl sulfides
-
Disulfide has been reduced by cerium trichloride and samarium in tetrahydrofuran to produce samarium thiolates. The "living" species reacts smoothly with α,β-unsaturated esters(nitriles) to afford β-thioesters(nitrile) under mild and neutral conditions. The new thiolate anion also reacts with acyl halides, anhydrides and alkyl or benzyl halides to give thioesters and sulfides, respectively.
- Li, Xue,Zhang, Songlin,Zhang, Yongmin
-
p. 1527 - 1529
(2007/10/03)
-
- An improved, general procedure to S-aryl thiol esters: A new synthetic application of dry arenediazonium o-benzenedisulfonimides
-
The reaction between dry arenediazonium o-benzenedisulfonimides (1) and sodium thioacetate or thiobenzoate in anhydrous acetonitrile at room temperature is an efficient and safe procedure, of general validity, for the preparation of S-aryl thiol esters. The products can be easily purified and the yields are always very high. Of the 28 considered examples, the average yield of the S-aryl thioacetates (7) was 86% and that of the S-aryl thiobenzoates (8) 88%. It was possible to recover, in good amount and from all the reactions, o-benzenedisulfonimide (9), reusable for the preparation of salts 1.
- Barbero, Margherita,Degani, Iacopo,Dughera, Stefano,Fochi, Rita
-
p. 1225 - 1230
(2007/10/03)
-
- Convenient synthesis of thiol esters from acyl chlorides and disulfides using Zn/AlCl3
-
Various thiol esters were prepared by condensation of acyl chlorides with disulfides in the presence of Zn/AlCl3. The advantages of this method are high yields under relatively mild conditions, simple work-up, lack of toxicity, and low costs.
- Lakouraj, Moslem M.,Movassagh, Barahman,Fadaei, Zahra
-
p. 1085 - 1088
(2007/10/03)
-
- Mg2+-imidazole-catalyzed self-condensation of malonyl thioesters: Getting tuned for biomimetic polyketide synthesis?
-
We report that a subtle balance of carbanion reactivity, leaving group activation, and pKa of the catalyst is required for efficient self-condensation of thiomalonates to thioacetoacetates in up to 71% yield under "biomimetic" conditions originally proposed by Kobuke and Yoshida (Tetrahedron Lett. 1978, 19, 367).
- Sakai, Naomi,Sorde, Nathalie,Matile, Stefan
-
p. 845 - 851
(2007/10/03)
-
- A convenient one-pot synthesis of thiol esters from disulfides using a Zn/AlCl3 system
-
A novel synthetic procedure for the direct preparation of thiol esters from various disulfides and symmetrical anhydrides using a Zn/AlCl3 system is described.
- Movassagh,Lakouraj,Fadaei
-
-
- Chemoselective acetylation of alcohols, amines, and thiols without catalyst and solvent
-
Microwave induced rapid and selective acetylation of alcohols, amines and thiols with acetic anhydride was carried out under non-catalytic and solvent free conditions.
- Bandgar,Kasture,Kamble
-
p. 2255 - 2259
(2007/10/03)
-
- 1H, 13C and 17O NMR study of substituent effects in 4-substituted phenylthiol esters
-
The 1H and 13C NMR spectra of 4-substituted phenylthiol acetates, benzoates and cinnamates and the 17O NMR spectra of a few thiol acetates were measured. The 13C chemical shifts of C-1 of the thiol esters when correlated with appropriate substituent-induced chemical shifts (SCS) of monosubstituted benzenes reveal an enhancement of substituent effect at C-1. Several good dual substituent parameter (DSP) correlations of 13C chemical shifts with σ1 and σR parameters were obtained for the carbons para to the substituent and the carbonyl carbons of all the three series of thiol esters display inverse substituent effects, indicating π-polarization of the thiol ester functionality by the dipole of the substituent. John Wiley & Sons Ltd.
- Perumal, Subbu,Vasuki, Gnanasambandam,Vijayabaskar, Veerappan,Selvaraj, Sangavanaicker,Boykin, David W.
-
p. 720 - 726
(2007/10/03)
-
- Kinetics and Mechanism of the Aminolysis of Phenyl Dithioacetates in Acetonitrile
-
The aminolysis reactions of phenyl dithioacetates with anilines (AN), N,N-dimethylanilines (DMA), and benzylamines (BA) in acetonitrile are investigated. The mechanism is relatively simple, involving a zwitterionic tetrahedral intermediate, T±, and is uncomplicated by the fast proton transfer step which may become rate limiting in the aminolysis of thiono and dithio esters and carbonates with poor leaving groups in water. The mechanism changes from rate-limiting expulsion of the leaving group with βX = 0.80-0.86 and βZ = -0.71 to -0.84 for ANs and DMAs to rate-limiting attack by the nucleophile with much smaller magnitudes of βX and βZ for BAs. The relatively large βXZ values for the former series and a smaller βXZ for the latter series support the proposed mechanistic change.
- Oh, Hyuck Keun,Woo, So Young,Shin, Chul Ho,Park, Young Sook,Lee, Ikchoon
-
p. 5780 - 5784
(2007/10/03)
-
- A New and Efficient Esterification Reaction via Mixed Anhydrides by the Promotion of a Catalytic Amount of Lewis Acid
-
In the presence of a catalytic amount of Lewis acid, various carboxylic esters or S-phenyl carbothioates are prepared in excellent yields by the respective reactions of equimolar amounts of silyl carboxylates and alkyl silyl ethers or phenyl silyl sulfides with 4-trifluoromethylbenzoic anhydride.
- Miyashita, Mitsutomo,Shiina, Isamu,Miyoshi, So,Mukaiyama, Teruaki
-
p. 1516 - 1527
(2007/10/02)
-
- A New and Efficient Method for the Preparation of S-Phenyl Carbothioates via Mixed Anhydrides Using Active Titanium(IV) Salts
-
In the presence of a catalytic amount of titanium(IV) salt, various S-phenyl carbothioates are prepared in excallent yields by the reaction of nearly equimolar amounts of silyl derivatives of carboxylic acids and benzenethiols with p-trifluoromethylbenzoic anhydride.
- Mukaiyama, Teruaki,Miyashita, Mitsutomo,Shiina,, Isamu
-
p. 1747 - 1750
(2007/10/02)
-
- Hypervalent iodine in synthesis; 5. The reaction between diaryliodonium salts and thiocarboxylic acid salts: A convenient method for the synthesis of S-aryl thiocarboxylates
-
A convenient method for the synthesis of S-aryl thiocarboxylates by the S-arylation of potassium thioacetate or potassium thiobenzoate with diaryliodonium chlorides or iodides in dimethylformamide is reported.
- You,Chen
-
p. 521 - 522
(2007/10/02)
-
- Leaving Group Effects in Thiolester Hydrolysis. Part 2. On the Possibility of an Elimination-Addition (Keten) Mediated Pathway in S-Acetylcoenzyme A Basic Hydrolysis and Acetyl Transfer
-
Alkaline hydrolysis rates (kHO(1-)) at 25 deg C in aqueous solution for a series of S-alkyl and S-aryl thiolacetates, including S-acetylcoenzyme A, were correlated (as their logarithms) with the pKa of the conjugate acid of the thiolate leaving group to give a slope (βl.g.) of -0.33.In comparison with the corresponding oxygen esters, thiolesters are, for the basicity of a given leaving species, one to two orders of magnitude less reactive towards hydroxide ion and show little dispersion into aryl and alkyl leaving groups, ascribed to the lower steric sensitivity of thiolacetate esters compared with the oxygen analogues.The small value of βl.g. and the lower reactivity of S- than O-esters are offered as evidence of a bimolecular associative (BAc2) mechanism for basic hydrolysis.The E2 route is excluded by the lack of deuterium incorporation into the (acetate) product of hydrolysis.In spite of the accepted acidity of thiolacetates, a kinetically insignificant amount of ester conjugate base is formed in aqueous solution even at high, non-physiological pH and thus S-acetylcoenzyme A does not hydrolyse by an E1cB pathway.
- Douglas, Kenneth T.,Yaggi, Norbert F.,Mervis, Cynthia M.
-
p. 171 - 174
(2007/10/02)
-