- Base-Catalyzed Transesterification of Thionoesters
-
Here we report a convenient synthesis of thionoesters by base-catalyzed transesterification. Benzyl and alkyl thionobenzoates and thionoheterobenzoates were efficiently prepared using various alcohols catalyzed by the corresponding sodium alkoxide. This methodology features a broad substrate scope, good to excellent yields, short reaction times, while simultaneously driving the reaction toward completion through the removal of the methanol byproduct. We also report the conversion of a small collection of thionobenzoates into the corresponding α,α-difluorobenzyl ethers to demonstrate the conversion of alcohols into difluorobenzyl or difluoroheterobenzyl ethers, a process that could prove useful for lead optimization in medicinal chemistry.
- Newton, Josiah J.,Britton, Robert,Friesen, Chadron M.
-
p. 12784 - 12792
(2018/10/20)
-
- An Expeditious Route to trans-Configured Tetrahydrothiophenes Enabled by Fe(OTf)3-Catalyzed [3+2] Cycloaddition of Donor–Acceptor Cyclopropanes with Thionoesters
-
A synthetic route to trans-configured tetrahydrothiophenes (THTs) through Fe(OTf)3-promoted [3+2] cycloaddition of donor–acceptor cyclopropanes with thionoesters was developed. The cycloaddition proceeded in high yield with high diastereoselectivity, affording transient α-alkoxy THTs. Not only aromatic and aliphatic thionoesters, but also thionolactone were applicable to the present iron catalysis. Further transformation of the S,O-ketal functionality of the product was achieved in a highly trans diastereoselective manner. Moreover, the utility of our methodology was clearly demonstrated by the synthesis of enantioenriched trans-configured THTs.
- Matsumoto, Yohei,Nakatake, Daiki,Yazaki, Ryo,Ohshima, Takashi
-
supporting information
p. 6062 - 6066
(2018/03/28)
-
- Facile Synthesis of 2,5-Disubstituted Thiazoles from Terminal Alkynes, Sulfonyl Azides, and Thionoesters
-
A sequential procedure for the synthesis of 2,5-disubstituted thiazoles from terminal alkynes, sulfonyl azides, and thionoesters is reported. A copper(I)-catalyzed 1,3-dipolar cycloaddition of terminal alkynes with sulfonyl azides affords 1-sulfonyl-1,2,3-triazoles, which then react with thionoesters in the presence of a rhodium(II) catalyst. The resulting 3-sulfonyl-4-thiazolines subsequently aromatize into the corresponding 2,5-disubstituted thiazoles by elimination of the sulfonyl group. (Chemical Equation Presented).
- Miura, Tomoya,Funakoshi, Yuuta,Fujimoto, Yoshikazu,Nakahashi, Junki,Murakami, Masahiro
-
supporting information
p. 2454 - 2457
(2015/05/27)
-
- Aromatic selenoic,selenothioic,and diselenoic acid salts:isolation, characterization, and 77senmr spectra,together with theoretical elucidation
-
To systematically elucidate molecular and electronic structures of aromatic selenoic acid salts and their heavier congeners, they were synthesized by reacting selenoic, selenothioic, and diselenoic acid Se-[2-(trimethylsilyl) ethyl] esters with ammonium f
- Murai, Toshiaki,Nishi, Daisuke,Hayashi, Satoko,Nakanishi, Waro
-
supporting information
p. 677 - 692
(2014/07/08)
-
- Methanolysis of thioamide promoted by a simple palladacycle is accelerated by 108 over the methoxide-catalyzed reaction
-
Palladacycle 1 catalyzes the methanolytic cleavage of N-methyl-N-(4- nitrophenyl)thiobenzamide (4) via a mechanism involving formation of a Pd-bound tetrahedral intermediate (TI). The rate constant for decomposition of the complex formed between 1, methox
- Liu, C. Tony,Maxwell, Christopher I.,Pipe, Stephanie G.,Neverov, Alexei A.,Mosey, Nicholas J.,Brown, R. Stan
-
supporting information; experimental part
p. 20068 - 20071
(2012/02/02)
-
- P4S10/dimethicone tandem: Efficient reagent for thionation of various aromatic amides and esters
-
Organosulfur compounds are valuable because of their rich and varied chemistry especially in biological field. We report a new and efficient way for thionation of various aromatic amides and esters using P4S 10/ dimethicone tandem. The ease of handling and higher yield makes this protocol economical.
- Cho, Dongho,Ahn, Jiyoung,De Castro, Kathlia A.,Ahn, Hyunseok,Rhee, Hakjune
-
supporting information; experimental part
p. 5583 - 5588
(2010/10/02)
-
- Disparate behavior of carbonyl and thiocarbonyl compounds: Acyl chlorides vs thiocarbonyl chlorides and isocyanates vs isothiocyanates
-
(Figure Presented) The reaction of benzoyl chloride with methanol catalyzed by pyridine is 9 times more rapid than is the same reaction with thiobenzoyl chloride. The difference in reactivity, as well as the dealkylation reactions that occur when the reaction of thiobenzoyl chloride is catalyzed by bases such as Et3N, can be understood in terms of the charge distributions in the intermediate acylammonium ions. The reaction of PhNCO with ethanol occurs at a much higher rate (4.8 × 104) than that of PhNCS, corresponding to a difference in activation free energies for the additions of 6 kcal/mol. Transition states for each of these reactions were located, and each involves two alcohol molecules in a hydrogen bonded six-membered ring arrangement. Information concerning differences in reactivity was derived from analysis of Hirshfeld atomic charge distributions and calculated hydrogenolysis reaction energies.
- Wiberg, Kenneth B.,Wang, Yi-Gui,Miller, Scott J.,Puchlopek, Angela L. A.,Bailey, William F.,Fair, Justin D.
-
experimental part
p. 3659 - 3664
(2009/09/26)
-
- Facile conversion of dithioesters into carboxylic acids or esters using alkaline hydrogen peroxide
-
Simple, mild, and environmentally friendly procedures for the direct conversion of dithioesters into either carboxylic acids or esters using hydrogen peroxide under alkaline conditions are described. Georg Thieme Verlag.
- Grellepois, Fabienne,Portella, Charles
-
experimental part
p. 3443 - 3446
(2009/05/09)
-
- 2,4-Disubstituted-5-acetoxythiazoles: useful intermediates for the synthesis of thiazolones and 2,4,5-trisubstituted thiazoles
-
A variety of 2,4-disubstituted-5-acetoxythiazoles were prepared from the substituted methyl benzoates in good to moderate yields using a three-step sequence: (1) ester to thionoester conversion, (2) coupling with an amino acid, and (3) acetic anhydride me
- Qiao,Dominique,Goodnow Jr.
-
p. 3682 - 3686
(2008/09/20)
-
- Thionation of esters and lactones with the reagent combination of phosphorus pentasulfide and hexamethyldisiloxane
-
The combination of P4S10 and hexamethyldisiloxane converts esters and lactones to thionoesters and thionolactones in yields comparable to or superior to those obtained with Lawesson's reagent. The method has the advantage that reagent-derived byproducts may be removed by a simple hydrolytic workup or by filtration through silica gel, rather than by chromatography, as required for Lawesson's reagent.
- Curphey, Thomas J
-
p. 371 - 373
(2007/10/03)
-
- Thionation with the reagent combination of phosphorus pentasulfide and hexamethyldisiloxane
-
The combination of P4S10 and hexamethyldisiloxane efficiently converts esters, lactones, amides, lactams, and ketones to their corresponding thiono derivatives. In the presence of elemental sulfur, 3-oxoesters are converted to dithiolethiones by this reagent. Yields are comparable to or superior to those obtained with Lawesson's reagent. The method has the advantage that reagent-derived byproducts may be removed by a simple hydrolytic workup or by filtration through silica gel, rather than by chromatography, as required for Lawesson's reagent.
- Curphey, Thomas J.
-
p. 6461 - 6473
(2007/10/03)
-
- Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 15. Generation of alkoxycarbonyl(sulfenyl)carbenes and their intramolecular insertion to give alkenyl sulfides
-
A range of 18 alkoxycarbonyl sulfinyl phosphorus ylides 9 have been prepared and their behaviour upon flash vacuum pyrolysis (FVP) at 600 deg C examined. For R1 = H, Me and Et they lose Ph3PO and in some cases Ph3P to give mixtures of products including the alkenyl sulfides 10, the sulfides 11, the disulfides 12 and the thioesters 14. The alkenyl sulfides 10 most likely arise from intramolecular insertion of the alkoxycarbonyl sulfenyl carbenes resulting from loss off Ph3PO to produce β-lactones which then lose CO2 and this is supported by the results from 13C labelled ylides. Possible mechanisms for the formation of 11 and 14 are also presented and the feasibility of various steps has been examined by preparation and pyrolysis of the proposed intermediates. In contrast, pyrolysis of the ylides 9 where R1 = Ph and the tert-butoxycarbonyl ylides 30 leads mainly to complete fragmentation with loss of Ph3PO and benzyl alcohol or 2-methylpropan-2-ol and does not give any useful sulfur-containing products. Four alkoxy-carbonyl sulfonyl diazo compounds 33 have been prepared and in three cases they give the alkenyl sulfones 34 upon FVP at 400 deg C, probably by an intramolecular insertion and decarboxylation process analogous to the formation of 10 from 9. On the other hand the alkoxycarbonyl carbenes produced by FVP of the amino acid-derived diazo compounds 35 undergo alternative proocesses with no sign of β-lactone formation. Fully assigned 13C NMR data are presented for 13 of the ylides.
- Aitken, R. Alan,Armstrong, Jill M.,Drysdale, Martin J.,Ross, Fiona C.,Ryan, Bruce M.
-
p. 593 - 604
(2007/10/03)
-
- Microwave-accelerated solvent-free synthesis of thioketones, thiolactones, thioamides, thionoesters, and thioflavonoids
-
Formula presented An expeditious, solvent-free, and high yield conversion of ketones, flavones, isoflavones, lactones, amides, and esters to the corresponding thio analogues is described utilizing Lawesson's reagent in a process that circumvents the use of dry solvents and excess of the reagent.
- Varma, Rajender S.,Kumar, Dalip
-
p. 697 - 700
(2008/02/11)
-
- Bis(2-methoxyethyl)aminosulfur trifluoride: A new broad-spectrum deoxofluorinating agent with enhanced thermal stability
-
Bis(2-methoxyethyl)aminosulfur trifluoride, (CH3OCH2CH2)2NSF3 (Deoxo-Fluor reagent), is a new deoxofluorinating agent that is much more thermally stable than DAST (C2H5)2NSF3 and its congeners. It is effective for the conversion of alcohols to alkyl fluorides, aldehydes/ketones to the corresponding gem-difluorides, and carboxylic acids to the trifluoromethyl derivatives with, in some cases, superior performance compared to DAST. The enhanced stability is rationalized on the basis of conformational rigidity imposed by a coordination of the alkoxy groups with the electron-deficient sulfur atom of the trifluoride.
- Lal, Gauri S.,Pez, Guido P.,Pesaresi, Reno J.,Prozonic, Frank M.,Cheng, Hansong
-
p. 7048 - 7054
(2007/10/03)
-
- Laser flash photolysis studies of oxygen and sulfur atom transfer reactions from oxiranes and thiiranes to singlet carbenes
-
Laser flash photolysis (UV-LFP) studies of benzylchlorodiazirine (1a), phenylchlorodiazirine (1b), phenylmethoxydiazirine (1c), 2,2-dimethoxy-5,5- dimethyl-Δ3-1,3,4-oxadiazoline (6a), 3,4-diaza-2,2-dimethoxy 1- oxa[4.3]spirooct-3-ene (6b), 5',5'-dimethoxyspiro[adamantane]-2,2 -[Δ3- 1,3,4-oxadiazoline] (6c), and diazofluorene (DAF) in the presence of oxiranes and thiiranes are reported. These compounds, upon irradiation, afford benzylchlorocarbene (2a), phenylchlorocarbene (2b), methoxyphenylcarbene (2c), dimethylcarbene (8a), cyclobutylidene (8b), adamantylidene (8c), and fluorenylidene (FL), respectively. Absolute rate constants for the transfer of oxygen and sulfur atoms to these carbenes have been determined in both acetonitrile and cyclohexane solvents. These carbenes abstract oxygen and sulfur atoms with bimolecular rate constants ranging from 104 to 1010 M- 1 s-1 at 22 °C. Ylides from attack of carbenes onto heteroatom donors were not observed for any of the heteroatom transfer reactions. It was found that the magnitudes of the rate constants for heteroatom transfer are dependent on the philicity of the carbene intermediate, and trends in the kinetic data suggest that oxygen and sulfur atom transfers occur by concerted mechanisms through ylide-like transition states. The reactions of dimethoxycarbene (14) with cyclohexene oxide and propylene sulfide have been studied by the thermolysis of 6a, in benzene, at 110 °C. It was found that dimethoxycarbene also abstracts oxygen and sulfur atoms, albeit in low yields. It is concluded that, for singlet carbenes, carbene electrophiiicity is important in these heteroatom transfer processes.
- Pezacki, John Paul,Wood, Paul D.,Gadosy, Timothy A.,Lusztyk, Janusz,Warkentin, John
-
p. 8681 - 8691
(2007/10/03)
-
- Conversion of Esters to α,α-Difluoro Ethers using Bromine Trifluoride
-
Bromine trifluoride reacts rapidly with O-substituted thioesters to forms α,α-difluoro ethers, a family of almost unknown compounds.
- Rozen, Shlomo,Mishani, Eyal
-
p. 1761 - 1762
(2007/10/02)
-
- Dithio and Thiono Esters, 55. - Synthesis of N-Protected, Optically Active α-Amino Thiono Esters
-
The N-protected α-amino amides 1 are O-alkylated with trialkyloxonium tetrafluoroborates to form the iminium salts 2.Sulfhydrolysis of 2 yields the α-amino thiono esters 3.This reaction sequence allows the preparation of enantiomerically pure 3.Key Words:
- Brutsche, Andreas,Hartke, Klaus
-
p. 921 - 926
(2007/10/02)
-
- Formation of 1,3-Dithiolanes and 1,3-Dithianes on Electroreduction of ω-Chloroalkyl Dithiocarboxylates
-
Cyclic thioacetals of type 4 and 5 are formed by intramolecular nucleophilic attack in the cathodic reduction of the ω-chloroalkyl dithiocarboxylates 1 and 2.The yield of 2-tert-butyl-1,3-dithiane (4b) is 52percent, whereas elimination of dithiocarboxylate anions occurs to a considerable extent in the other cases.
- Gade, Thomas,Streek, Michael,Voss, Juergen
-
p. 2245 - 2250
(2007/10/02)
-
- Reduction of Thionoesters to Ethers by Triorganotin Hydrides
-
Esters 1 are efficiently deoxygenated to the corresponding ethers 3 in two steps by first conversion to the thionoesters 2 and subsequent reduction of these by triorganotin hydrides.
- Smith, Colin,Tunstad, Linda M.,Gutierrez, Carlos G.
-
p. 257 - 260
(2007/10/02)
-
- Electroreduction of Organic Compounds, 9. - Convenient Electrochemical Preparation of Thioacetals from Dithioesters
-
Thioacetals are obtained as main products on electroreduction of alkyl dithiocarboxylates of various types in the presence of dimethyl sulfate in methanol. (Z)- and (E)-1,2-diaryl-1,2-bis(methylthio)ethenes are formed as byproducts.No reduction to form be
- Drosten, Gisela,Mischke, Peter,Voss, Juergen
-
p. 1757 - 1762
(2007/10/02)
-
- Stereochemical Studies on Hemiorthothiol and Hemiorthothiolate Tetrahedral Intermediates
-
This study deals with hemiorthothiol-RC(OR')2SH-tetrahedral intermediates including (a) two acyclic ones of type , (b) two types of monocyclics and , and (c) four bicyclic systems , , , and .The breakdown of (R = Ph, R' = Et) led to thiono esters 34 and 35; that of (R = Me, Ph) resulted in hydroxy thiono esters 36-39, whereas the cleavage of (R =Me, Et) yielded thionolactones 49-53 and hydroxy thiono esters 55-58.The study of rigid bicyclic intermediates - helped uncover the role of stereoelectronic effects in the breakdown of hemiorthothiol tetrahedral intermediates.Finally, a family of isolable hemiorthothiolate tetrahedral intermediates-RC(OR')2S-+Na-viz. ->--> (monocyclic) and -> (bicyclic) is reported.
- Khouri, Farid F.,Kaloustian, Moses K.
-
p. 6683 - 6695
(2007/10/02)
-
- ELEKTROCHEMISCHE OXIDATION VON DITHIOCARBONSAEUREESTERN ZU ISOTHIAZOLEN
-
Electrolysis of alkyl arenedithioates 1 in acetonitrile with benzyl-triethyl-ammonium chloride as supporting electrolyte yields 5-aryl-4-cyano-3-methyl-isothiazoles 4.A reaction path is discussed according to which the dithioesters 1 are chlorinated at the anode and subsequently react with 3-iminobutyronitrile (6), generated at the cathode, to form the isothiazoles 4.
- Voss, Juergen,Mischke, Peter,Adiwidjaja, Gunadi
-
p. 261 - 274
(2007/10/02)
-
- Electroreduction of Organic Compounds. 4. Electrochemical Reduction of Mono- and Bis-dithiobenzoate Esters in the Presence of Bi- or Monofunctional Electrophiles
-
Co-electroreduction of methyl dithiobenzoate (1a) and 1,3-dimesyloxypropane (5) in acetonitrile yields the tetrahydrodithiepine 6, whereas the thiirane 9 is formed from trimethylene-1,3-bis-dithiobenzoate (7a) and methyl iodide.The bis-thioacetals 8 are obtained, if 7a and its homologue 7b are electrolized together with methyl iodide; the heterocyclic bis-thioacetal 10 is formed from 7c as a mixture of the meso- and d,l-diastereomers in acetonitrile.
- Voss, Juergen,Buelow, Christian Von,Drews, Torsten,Mischke, Peter
-
p. 519 - 526
(2007/10/02)
-
- REGIOSELECTIVITY OF METALATION OF 1,3-DITHIOLANES AND 1,3-DITHIOLANE 1-OXIDES
-
Deprotonation of 1,3-dithiolane 1-oxide (3) and tran-2-phenyl-1,3-dithiolane 1-oxide (5) leads to cleavage of the derived anions.Cleavage reactions do not occur with trans-hexahydro-1,3-benzodithiole (7), its 1-oxide, or its 1,1-dioxide all of which can b
- Carey, Francis A.,Dailey, Oliver D.
-
p. 169 - 174
(2007/10/02)
-
- New Conversion of Esters to Ethers and Its Application to the Preparation of Furano-18-crown-6
-
Thionoesters which are readily prepared from esters can be desulfurized with Raney nickel to form the corresponding ethers.This new synthetic pathway to convert esters to ethers avoids many of the steric and functional limitations of known methods and appears to be a general method for this conversion.
- Baxter, Steven L.,Bradshaw, Jerald S.
-
p. 831 - 832
(2007/10/02)
-