- Interrupted aza-Wittig reactions using iminophosphoranes to synthesize 11C-carbonyls
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A direct CO2-fixation methodology couples structurally diverse iminophosphoranes with various nucleophiles to synthesize ureas, carbamates, thiocarbamates, and amides, and is amenable for 11C radiolabeling. This methodology is practical, as demonstrated by the synthesis of >35 products and isolation of the molecular imaging radiopharmaceuticals [11C]URB694 and [11C]glibenclamide. This journal is
- Ismailani, Uzair S.,Munch, Maxime,Mair, Braeden A.,Rotstein, Benjamin H.
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supporting information
p. 5266 - 5269
(2021/06/06)
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- N -Acylbenzotriazoles as Proficient Substrates for an Easy Access to Ureas, Acylureas, Carbamates, and Thiocarbamates via Curtius Rearrangement Using Diphenylphosphoryl Azide (DPPA) as Azide Donor
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A diverse range of ureas, N -acylureas, carbamates, and thiocarbamates has been synthesized in good to excellent yields by reacting N -acylbenzotriazoles individually with amines or amides or phenols or thiols in the presence of diphenylphosphoryl azide (DPPA) as a suitable azide donor in anhydrous toluene at 110 °C for 3-4 hours. In this route, DPPA was found to be a good alternative to trimethylsilyl azide and sodium azide for the azide donor in Curtius degradation. The high reaction yields, one-pot and metal-free conditions, straightforward nature, easy handling, use of readily available reagents, and in many cases avoidance of column chromatography are the notable features of the devised protocol.
- Yadav, Mangal S.,Singh, Sumt K.,Agrahari, Anand K.,Singh, Anoop S.,Tiwari, Vinod K.
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p. 2494 - 2502
(2021/03/26)
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- Synthesis of carbamothioate derivatives via a copper catalyzed thiocarboxamidation of aryl iodides
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Abstract: A catalytic route to carbamothioate derivatives through a reaction involving isocyanides, elemental sulfur, and aryl iodides has been developed. The reaction scope has been examined using a range of isocyanides and aryl iodides. The reactions involve two consecutive C–S bond formations. Control experiment revealed that the reaction proceeds through an iminium species. Graphic abstract: [Figure not available: see fulltext.].
- Khalaj, Mehdi
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p. 945 - 952
(2020/05/26)
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- Thermolysis-Induced Two- or Multicomponent Tandem Reactions Involving Isocyanides and Sulfenic-Acid-Generating Sulfoxides: Access to Diverse Sulfur-Containing Functional Scaffolds
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Direct reaction of isocyanides with some sulfenic-acid-generating sulfoxides led to the effective formation of the corresponding thiocarbamic acid S-esters in good to high yields. A multicomponent reaction involving isocyanide, sulfoxide, and a suitable nucleophile has also been developed, providing ready access to a diverse range of sulfur-containing compounds, including isothioureas, carbonimidothioic acid esters, and carboximidothioic acid esters.
- Wu, Shengfeng,Lei, Xiaofang,Fan, Erkang,Sun, Zhihua
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p. 522 - 525
(2018/02/10)
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- One-pot synthesis of carbamates and thiocarbamates from Boc-protected amines
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A highly efficient one-pot procedure for the synthesis of carbamates and thiocarbamates has been described. In the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, the isocyanate intermediates were generated in situ for further reactions with alcohols and thiols to afford the desired carbamates and thiocarbamates in high yields.
- Kim, Hee-Kwon,Lee, Anna
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p. 4890 - 4892
(2016/10/21)
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- Facile one-pot synthesis of unsymmetrical ureas, carbamates, and thiocarbamates from Cbz-protected amines
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A novel one-pot synthesis of unsymmetrical ureas, carbamates and thiocarbamates from Cbz-protected amines has been developed. In the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, isocyanates are generated in situ, which facilitate rapid reaction with amines, alcohols, and thiols to afford the corresponding ureas, carbamates and thiocarbamates in high yields.
- Kim, Hee-Kwon,Lee, Anna
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supporting information
p. 7345 - 7353
(2016/08/05)
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- Synthesis of unsymmetrical ureas and S-thiocarbamates under catalyst-free conditions in a [BMIM]BF4 ionic liquid
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Unsymmetrical ureas and Sthiocarbamates were prepared in good to excellent yields by direct condensation of phenylurea with amines and thiols in 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) without the addition of any additives. The [BMIM]BF4 ionic liquid is a mild medium and can be recycled and reused several times.
- Hosseinzadeh, Rahman,Tajbakhsh, Mahmood,Aghili, Nora
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p. 175 - 182
(2015/05/27)
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- Preparation of ionic liquid-based vilsmier reagent from novel multi-purpose dimethyl formamide-like ionic liquid and its application
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In continuation of research to explore the applied potential of DMF-like ionic liquid, the ionic liquid version of N,N-dimethyliminiumchloride (Vilsmier reagent) has been synthesized from DMF-like ionic liquid and tested effectively for its capacity to achieve more useful organic transformations. The results show that DMF-like ionic liquid is world's first task specific ionic liquid which has catalyzed numerous diverse type of reaction and is multipurpose in its application. Thus a new term for this DMF-like ionic liquid has been coined that is DMF-like "multipurpose" ionic liquid. Copyright
- Hullio, Ahmed Ali,Mastoi
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p. 1647 - 1657
(2012/09/21)
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- Cyclodimerization and cyclotrimerization of isocyanates promoted by one praseodymium benzenethiolate complex [Pr(SPh)3(THF)3]
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The cyclotrimerization of aryl isocyanates and the cyclodimerization of alkyl isocyanates initiated by one praseodymium benzenethiolate complex [Pr(SPh)3(THF)3] were investigated. Comparative runs with [Pr(SPh)3(THF)3] and its precursor Pr[(Me 3Si)2N]3 showed that the former has the advantages of a higher selectivity toward isocyanates, easy preparation, low catalyst loading, high conversion as well as mild reaction conditions.
- Wang, He-Ming,Li, Hong-Xi,Yu, Xiang-Yang,Ren, Zhi-Gang,Lang, Jian-Ping
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experimental part
p. 1530 - 1535
(2011/04/15)
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- Thiol-isocyanate-ene ternary networks by sequential and simultaneous thiol click reactions
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Thiol-isocyanate-ene ternary networks with systematic variations (100/100/0, 100/80/20, 100/60/40, 100/40/60, 100/20/80, and 100/0/100) were prepared by sequential and simultaneous thiol-ene and thiol-isocyanate click reactions. The thiol-isocyanate coupling reaction was triggered thermally or photolytically to control the sequence with the thiol-ene photopolymerization. Triethyl amine (TEA) and 2,2-dimethoxy-2-phenyl acetophenone (DMPA) were used for the sequential thermally induced thiol-isocyanate coupling and photochemically initiated thiol-ene reaction, respectively. A thermally stable photolatent base catalyst (tributylaminetetraphenylborate salt, TBAHBPh 4) capable of in situ generation of tributylamine by UV light was used with isopropylthioxanthone (ITX) for the simultaneous thiol-isocyanate/ thiol-ene curing systems. The kinetics of the hybrid networks investigated using real-time IR indicate that both thiol-isocyanate and thiol-ene reactions were quantitatively rapid and efficient (>90% of conversion in a matter of minutes and seconds, respectively). The Tg of the thiourethane/thiol-ene hybrid networks progressively increases (-5 to 35 °C by DSC) as a function of the thiourethane content due to the higher extent of hydrogen bonding, also resulting in enhanced mechanical properties. Highly uniform and dense network structures exhibiting narrow full width at half-maximum (~10 °C) were obtained for both the sequential and the simultaneous thiol click reactions, resulting in identical thermal properties that are independent of the sequence of the curing processes.
- Shin, Junghwan,Matsushima, Hironori,Comer, Christopher M.,Bowman, Christopher N.,Hoyle, Charles E.
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scheme or table
p. 2616 - 2625
(2011/11/13)
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- Cyanuric chloride: an efficient reagent for the Lossen rearrangement
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An efficient method for the Lossen rearrangement that uses 2,4,6-trichloro-1,3,5-triazine (TCT) as a promoter is reported. This procedure allowed the preparation of various carbamates, thiocarbamates, and ureas in good yields directly from the correspondi
- Hamon, Florian,Prié, Gildas,Lecornué, Frédéric,Papot, Sébastien
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experimental part
p. 6800 - 6802
(2010/04/27)
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- Hindered ureas as masked isocyanates: Facile carbamoylation of nucleophiles under neutral conditions
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Bigger is better: Sterically hindered dialkyl ureas undergo nucleophilic substitution at dramatically faster rates than their less hindered counterparts (see scheme). Steric decompression upon the formation of an intermediate isocyanate can explain this c
- Hutchby, Marc,Houlden, Chris E.,Gair Ford,Tyler, Simon N. G.,Gagne, Michel R.,Lloyd-Jones, Guy C.,Booker-Milburn, Kevin I.
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supporting information; experimental part
p. 8721 - 8724
(2010/01/16)
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- A selenium-catalysed synthesis of thiocarbamates from nitroarenes, carbon monoxide and thiols under mild conditions
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An improved method for the selenium-catalysed synthesis of thiocarbamates under mild conditions has been developed. With acetone as solvent, the one-pot selenium-catalysed carbonylation of nitroarenes and thiols with carbon monoxide proceeds smoothly at atmospheric pressure and ambient temperature.
- Zhang, Xiao-Peng,Lu, Shi-Wei
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experimental part
p. 589 - 591
(2009/08/15)
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- Synthesis of thiocarbamates from thiols and isocyanates under catalyst- and solvent-free conditions
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A simple and efficient procedure was developed for the synthesis of S-alkyl (aryl) thiocarbamates under solvent-free conditions without the use of a catalyst. The significant features of this protocol are (a) operational simplicity, (b) mild reaction cond
- Movassagh, Barahman,Soleiman-Beigi, Mohammad
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p. 137 - 140
(2008/09/20)
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- Kinetics and mechanism of the anilinolysis of S-aryl N-arylthiocarbamates in acetonitrile
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The aminolysis reactions of S-aryl N-arylthiocarbamates (YC 6H4NH-C(=O)-SC6H4Z, 1) with anilines in acetonitrile are studied. The reaction rates are more influenced by the nucleophilicity of the nucleophile than the nucleofugality of the leaving group, but the change In the effective charge from reactants to the TS for formation of the tetrahedral intermediate is slightly greater in the leaving group (βz from-0.07 to -0.14) than In the nucleophile (βx = 0.04-0.12). The magnitude of the Broensted coefficients are in the range of values that are consistent for a stepwise mechanism with rate-limiting formation of the zwitterionic tetrahedral intermediate. Signs of cross-interaction constants, ρxy (>0), ρxz (>0) and ρyz (0), are all consistent with a stepwise mechanism. It Is concluded that the change of the amine from benzylamines to anilines causes a shift of the aminolysis mechanism from a concerted to a stepwise process. Copyright
- Sung, Dae Dong,Jang, Hee Man,Jung, Dae Il,Leeb, Ikchoon
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experimental part
p. 1014 - 1019
(2009/10/26)
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- One-pot direct synthesis of thiocarbamates from aniline, carbon monoxide, and thiols catalyzed by selenium
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Catalyzed by selenium, oxidative carbonylation of aniline and thiols with carbon monoxide and oxygen affords the corresponding thiocarbamates mostly in moderate to good yields under solvent-free conditions at ambient temperature. Copyright Taylor & Franci
- Zhang, Xiaopeng,Lu, Shiwei
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p. 3291 - 3299
(2008/02/12)
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- A novel one-pot solvent-free, triethylamine-assisted, selenium-catalyzed synthesis of thiocarbamates from nitroarenes, carbon monoxide, and thiols
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A novel one-pot solvent-free synthesis of a series of thiocarbamates is reported. Nitroarenes, carbon monoxide, and thiols are the starting materials, with cheap element selenium as catalyst; this method offers a simple access to thiocarbamates mostly in moderate to good yields. The selenium catalyst can be easily recovered and recycled. Georg Thieme Verlag Stuttgart.
- Zhang, Xiaopeng,Lu, Shiwei
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p. 1535 - 1538
(2007/10/03)
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- A new and facile route for the synthesis of thiocarbamates from aniline, carbon monoxide, and thiols mediated by selenium
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A new and facile route for the synthesis of thiocarbamates was reported. Mediated by selenium, aniline reacts very readily with carbon monoxide and thiols in the presence of triethylamine, to afford the corresponding thiocarbamates mostly in moderate to excellent yields under mild reaction conditions. Selenium can be easily recovered and recycled. Copyright
- Zhang, Xiaopeng,Lu, Shiwei
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p. 606 - 607
(2007/10/03)
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- Nucleophilic Substitution Reactions of Aryl N-Phenyl Thiocarbamates with Benzylamines in Acetonitrile
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The aminolysis reactions of aryl N-phenythiocarbamates (PhNHC(=O)SC 6H4Z; 3b) with benzylamines (XC6H 4CH2NH2) acetonitrile are studied. Rates are much faster than the corresponding reactions of aryl N-phenylcarbamates (PhNHC(=O)OC6H4Z; 3a). The rate increase from 3a to 3b is greater than that expected from substitution of thiophenoxide for phenoxide leaving group in the stepwise aminolysis reactions of esters. This large rate increase and the similar change in the aminolysis rates that are reported to occur from aryl ethyl carbonate (EtOC(=O)OC6H4Z; 2a) to aryl ethylthiocarbonate (EtOC(=O)SC6H4Z; 2b) lead us to conclude that the aminolysis of 3b proceeds by a concerted mechanism in contrast to a stepwise process for 3a. The negative ρxz values (-0.63) and violation of the reactivity-selectivity principle (RSP) support the proposed mechanism. The large βx values (1.3-1.5) obtained are considered to indicate a large degree of bond making in the transition state, which is consistent with the relatively large kinetic isotope effects (k H/kD > 1.0) observed.
- Oh, Hyuck Keun,Park, Jie Eun,Sung, Dae Dong,Lee, Ikchoon
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p. 3150 - 3153
(2007/10/03)
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- The Kinetics and Mechanism of the Thallium(III) Ion-promoted Hydrolysis of Thiolurethanes in Aqueous Solution. A Metal Ion-promoted Elimination
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The hydrolysis of thiolurethanes R1C6H4NHCOSC6H4R2 (1), in dilute aqueous perchloric acid, under conditions where the spontaneous hydrolysis is negligible, is promoted by Ti3+ ions.The organic products are the corresponding anilinium ion and the thalium salt of the thiophenol.The effects of substituent changes (R1,R2) of changes in +>, temperature, ionic strength, and of replacement of the NH proton by Me, are all compatible with hydrolysis occurring by elimination-addition mechanisms via the isocyanate as a reactive intermediate; thalium ion-promoted E1 cb and E2 routes are implicated.In effect the elimination-addition type of mechanism which is important for these esters at higher pH has been made available at low pH by complexation with Tl3+ ions.With the thiolurethanes RC6H4NHCOSEt, (2) which are less susceptible to the spontaneous and base-catalysed elimination-addition mechanisms of hydrolysis than are thiolurethanes (1), the presence of Tl3+ ions can also lead to promoted hydrolysis via elimination, but an AAc1-like route (with Tl3+ taking the role of H+) seems to be available to the N-Me derivatives.
- Satchell, Derek P. N.,Satchell, Rosemary S.,Wassef, Wasfy N.
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p. 1199 - 1202
(2007/10/02)
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- N-Nitroso Compounds. IV. Reaction of N-Nitrosourea with Thiol. A New Synthesis of Thiocarbamic S-Esters
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Thirteen thiocarbamic S-esters have been prepared in good yield by the reaction of thiol with substituted N-methyl-N-nitrosourea in anhydrous acetonitrile.
- Yoshida, Kitaro,Isobe, Masayoshi,Yano, Kazuyuki,Nagamatsu, Kazuo
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p. 2143 - 2144
(2007/10/02)
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- The E1cB Mechanism for Thiocarbamate Ester Hydrolysis: Equilibrium and Kinetic Studies
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The alkaline hydrolyses of a series of S-aryl thiocarbamate esters have been measured and the mechanism confirmed to be dissociative.Equilibrium constant for the synthesis of thiocarbamates from thiol and isocyanic acid have been obtained for aqueous media using both kinetic and analytical techniques.Hammett and Broensted parameters for the equilibrium reaction indicate that there is less positive effective charge on the sulphur in the thiocarbamate compared with that on the oxygen in the oxygen analogue.Theoretical arguments are advanced to show that the dissociative reactions of simple carbamate anions involve a planar geometry of the paticipating atoms.
- Bourne, Nicholas,Williams, Andrew,Douglas, Kenneth T.,Penkava, Thomas R.
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p. 1827 - 1832
(2007/10/02)
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- HYDROLYSIS KINETICS AND MECHANISM OF DIARYLTHIOCARBAMATES IN 20percent AQUEOUS DIOXANE MEDIUM
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Substituted S-aryl and O-aryl N-arylthiocarbamates have been synthetized.Kinetic studies of hydrolysis of these compounds in 20percent aqueous dioxane prove the ElcB mechanism.The found Hammett reaction constants, activation entropy values, Broensted coefficients, and comparison of reactivity with N-methyl analogues have been discussed as criteria of the mentioned mechanism.Hydrolysis results of thiocarbamates and carbamates in the same medium are compared.
- Mindl, Jaromir,Balcarek, Pavel,Silar, Lubomir,Vecera, Miroslav
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p. 3130 - 3139
(2007/10/02)
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