- A Mild Heteroatom (O -, N -, and S -) Methylation Protocol Using Trimethyl Phosphate (TMP)-Ca(OH) 2Combination
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A mild heteroatom methylation protocol using trimethyl phosphate (TMP)-Ca(OH)2combination has been developed, which proceeds in DMF, or water, or under neat conditions, at 80 °C or at room temperature. A series of O-, N-, and S-nucleophiles, including phenols, sulfonamides, N-heterocycles, such as 9H-carbazole, indole derivatives, and 1,8-naphthalimide, and aryl/alkyl thiols, are suitable substrates for this protocol. The high efficiency, operational simplicity, scalability, cost-efficiency, and environmentally friendly nature of this protocol make it an attractive alternative to the conventional base-promoted heteroatom methylation procedures.
- Tang, Yu,Yu, Biao
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- Nanosized CdS as a Reusable Photocatalyst: The Study of Different Reaction Pathways between Tertiary Amines and Aryl Sulfonyl Chlorides through Visible-Light-Induced N-Dealkylation and C-H Activation Processes
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It has been found that the final products of the reaction of sulfonyl chlorides and tertiary amines in the presence of cadmium sulfide nanoparticles under visible light irradiation are highly dependent on the applied reaction conditions. Interestingly, with the change of a reaction condition, different pathways were conducted (visible-light-induced N-dealkylation or sp3 and sp2 C-H activation) that lead to different products such as secondary amines and various sulfonyl compounds. Remarkably, all of these reactions were performed under visible light irradiation and an air atmosphere without any additive or oxidant in benign solvents or under solvent-free conditions. During this study, the CdS nanoparticles as affordable, heterogeneous, and recyclable photocatalysts were designed, successfully synthesized, and fully characterized and applied for these protocols. During these studies, intermediates resulting from the oxidation of tertiary amines are trapped during the photoinduced electron transfer (PET) process. The reaction was carried out efficiently with a variety of substrates to give the corresponding products at relatively short times in good to excellent yields in parallel with the use of the visible light irradiation as a renewable energy source. Most of these processes are novel or are superior in terms of cost-effectiveness, safety, and simplicity to published reports.
- Firoozi, Somayeh,Hosseini-Sarvari, Mona
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p. 2117 - 2134
(2021/02/05)
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- Debenzylative Sulfonylation of Tertiary Benzylamines Promoted by Visible Light
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An efficient, general, inexpensive, and environmentally friendly photosynthesis of sulfonamides via visible light promoted debenzylative sulfonylation of tertiary benzylamines is described. Compared to the traditional S?N coupling reactions, which are promoted by oxidative C?N bond cleavage of symmetrical tertiary alkylamines, this strategy provides a selective C?N bond cleavage protocol and avoids the use of transition-metal, explosive oxidants, and ligands.
- Fu, Ying,Wu, Qing-Kui,Du, Zhengyin
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supporting information
p. 1896 - 1900
(2021/04/06)
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- Transition-Metal-Free and Visible-Light-Mediated Desulfonylation and Dehalogenation Reactions: Hantzsch Ester Anion as Electron and Hydrogen Atom Donor
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Novel approaches for N- and O-desulfonylation under room temperature (rt) and transition-metal-free conditions have been developed. The first methodology involves the transformation of a variety of N-sulfonyl heterocycles and phenyl benzenesulfonates to the corresponding desulfonylated products in good to excellent yields using only KOtBu in dimethyl sulfoxide (DMSO) at rt. Alternately, a visible light method has been used for deprotection of N-methyl-N-arylsulfonamides with Hantzsch ester (HE) anion serving as the visible-light-absorbing reagent and electron and hydrogen atom donor to promote the desulfonylation reaction. The HE anion can be easily prepared in situ by reaction of the corresponding HE with KOtBu in DMSO at rt. Both protocols were further explored in terms of synthetic scope as well as mechanistic aspects to rationalize key features of desulfonylation processes. Furthermore, the HE anion induces reductive dehalogenation reaction of aryl halides under visible light irradiation.
- Heredia, Micaela D.,Guerra, Walter D.,Barolo, Silvia M.,Fornasier, Santiago J.,Rossi, Roberto A.,Budén, Mariá E.
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supporting information
p. 13481 - 13494
(2020/12/15)
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- KMnO4-mediated oxidative C[sbnd]N bond cleavage of tertiary amines: Synthesis of amides and sulfonamides
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KMnO4-mediated oxidative C[sbnd]N bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.
- Zhang, Zhang,Liu, Yong-Hong,Zhang, Xi,Wang, Xi-Cun
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p. 2763 - 2770
(2019/04/10)
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- Method for selective N-methylation of secondary amide
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The invention relates to a method for selective N-methylation of secondary amide. The method is characterized in that the secondary amide is in an organic solvent N, N-dimethyl formamide or dimethyl sulfoxide, trifluoroacetic acid methyl ester serves as a methylation reagent, and reaction is performed in the presence of sodium hydride, potassium tert-butoxide or sodium methylate, so as to obtain aselective N-methylated product. The method has the characteristics that generally a trifluoroacetylation product is produced when the trifluoroacetic acid methyl ester is reacted with amine compounds, however a N-methylated product can be selectively obtained when the trifluoroacetic acid methyl ester is reacted with secondary amide; the method is simple to operate, low in cost, mild in reactionconditions and high in selectivity, and avoids the use of hypertoxic methylation reagents, such as dimethyl sulfate and methyl iodide.
- -
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Paragraph 0011
(2019/03/08)
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- Aryl sulfonamide tertiary amine compound synthesizing method
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The invention provides an aryl sulfonamide tertiary amine compound synthesizing method. According to the method, in an anhydrous aprotic solvent and under nitrogen protection, acryl sulfonyl chlorideand di-tertiary amine react for 1 to 12 hours according to a molar ratio of (1 to 1) to (1 to 20) under the condition of 50 to 150 DEG C, and the aryl sulfonamide tertiary amine compound can be obtained by purification. According to the method disclosed by the invention, the acryl sulfonyl chloride and the di-tertiary amine can directly generate C-S bond formation in the aprotic solvent and generate C-N bond breakage at the same time. According to the one-step aryl sulfonamide synthesizing method, raw materials are easy to obtain, a synthesizing technology is simple, operation is convenient, cost is low, and yield is high.
- -
-
Paragraph 0019
(2018/05/16)
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- Charge-Transfer Complex Promoted Regiospecific C?N Bond Cleavage of Vicinal Tertiary Diamines
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A catalyst-free, charge-transfer complex promoted coupling of sulfonyl chlorides with vicinal tertiary diamines to generate sulfonamides is presented. Mechanistic studies showed that these reactions are proceeded via charge transfer of vicinal tertiary diamines to sulfonyl chlorides, forming the unstable sulfonyl quaternary ammonium like complexes which induced the regiospecific intramolecular C?N bond cleavage of vicinal tertiary diamines. (Figure presented.).
- Fu, Ying,Xu, Qin-Shan,Shi, Chun-Zhao,Du, Zhengyin,Xiao, Caiqin
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supporting information
p. 3502 - 3506
(2018/09/14)
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- Preparation method of sulfonamide compounds
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The invention provides a synthetic method of sulfonamide compounds. 1,2-dibromoethane is taken as an oxidizing agent, iodide is taken as an iodine source, sulfinate and amine compounds in the mole ratio being 2:1 are subjected to oxidative coupling in an organic solvent at 50-90 DEG C for 1-12 h, and finally, the sulfonamide compounds are obtained through purification. By adopting 1,2-dibromoethane as the oxidizing agent and iodide as the iodine source, catalytic activity, selectivity and efficiency are high; reaction conditions are mild, cost is low, yield is high, and large-scale productionis facilitated.
- -
-
Paragraph 0016
(2018/09/13)
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- NaI-Catalyzed Oxidative Amination of Aromatic Sodium Sulfinates: Synergetic Effect of Ethylene Dibromide and Air as Oxidants
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A novel NaI-catalyzed oxidative amination of sodium sulfinates, employing both ethylene dibromide (EDB) and air as the oxidants, is described. EDB was first demonstrated to be a promising mild organic oxidant that in air, converted NaI into molecular iodine to promote the cross-coupling reactions of aromatic sodium sulfinates with amines to produce arylsulfonamides. Mechanistic studies indicated that a radical pathway might be involved in the reaction process.
- Fu, Ying,Li, Quan-Zhou,Xu, Qin-Shan,Hügel, Helmut,Li, Ming-Peng,Du, Zhengyin
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supporting information
p. 6966 - 6970
(2018/11/23)
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- Acceleration of Pd-Catalyzed Amide N-Arylations Using Cocatalytic Metal Triflates: Substrate Scope and Mechanistic Study
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The Pd/xantphos-catalyzed cross-coupling of amides and aryl halides is accelerated by cocatalytic metal triflate additives. A survey of nitrogen nucleophiles reveals improved yields for a variety of N-aryl amide products when Al(OTf)3 is employed as a catalytic additive, with some exceptions. Initial rates of catalysis indicate that the Lewis acid acceleration is more pronounced when bromobenzene (PhBr) is used in comparison with iodobenzene (PhI). The observation of an aryl halide dependence on rate and various qualitative kinetic experiments are consistent with a mechanism in which ligand exchange of halide for amide ("transmetalation") is turnover limiting. The mechanism may be different depending on whether PhBr or PhI is used as a coupling partner. Oxidative addition complexes (xantphos)Pd(Ph)(X) (X = Br, I; xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene), likely intermediates in catalysis, have been prepared; their differing interactions with Yb(OTf)3 in solution resemble the halide dependence of the catalytic mechanism, which we propose originates from a reversible Lewis acid mediated halide abstraction during catalysis.
- Becica, Joseph,Dobereiner, Graham E.
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p. 5862 - 5870
(2017/09/15)
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- Palladium-Catalyzed Regioselective Synthesis of 3-Arylindoles from N-Ts-Anilines and Styrenes
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A Pd-catalyzed intermolecular oxidative annulation between N-Ts-anilines and styrenes was developed. This method offers a straightforward and robust approach to a wide range of 3-arylindoles using readily available starting materials with good functional-group tolerance and high regioselectivity and efficiency. Further elaboration of the products obtained from this process provided access to highly functionalized and structurally diverse indoles, for example, 3-(indol-3-yl)carbazoles, 1,9-dihydropyrrolo-[2,3-b]carbazoles, and 3′-aryl-3,5′-biindoles.
- Youn, So Won,Ko, Tae Yun,Jang, Young Ho
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p. 6636 - 6640
(2017/05/29)
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- Cu-Mediated C-H 18F-Fluorination of Electron-Rich (Hetero)arenes
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This communication describes a method for the nucleophilic radiofluorination of electron-rich arenes. The reaction involves the initial C(sp2)-H functionalization of an electron-rich arene with MesI(OH)OTs to form a (mesityl)(aryl)iodonium salt
- McCammant, Matthew S.,Thompson, Stephen,Brooks, Allen F.,Krska, Shane W.,Scott, Peter J. H.,Sanford, Melanie S.
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supporting information
p. 3939 - 3942
(2017/07/26)
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- DBN hexafluorophosphate salts as convenient sulfonylating and phosphonylating agents
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Air-stable N-sulfonyl and N-phosphonyl DBN hexafluorophosphate salts have been synthesised under mild conditions as sulfonylating and phosphonylating agents. These salts are highly efficient in the sulfonylation and phosphonylation of a range of N- and O-nucleophiles to generate sulfonamides, sulfonate esters, phosphoramidates and phosphonate esters in good yields.
- Jones, Caroline S.,Bull, Steven D.,Williams, Jonathan M. J.
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p. 8452 - 8456
(2016/09/28)
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- NH4I-Catalyzed Synthesis of Sulfonamides from Arylsufonylhydrazides and Amines
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A novel and efficient approach to sulfonamides has been developed. Using TBHP as the oxidant and NH4I (20 mol%) as the catalyst, arylsulfonyl hydrazides reacted with amines to provide sulfonamides in moderate to good yields. Possible reaction pathway for the formation of the products was also discussed in this paper. Sulfonimides were synthesized through the oxidation coupling of arylsufonylhydrazides and amines by TBHP/NH4I system in moderate to good yields.
- Yu, Hui,Zhang, Yonghao
-
supporting information
p. 359 - 362
(2016/04/26)
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- Electrosynthesis of Arylsulfonamides from Amines and Sodium Sulfinates Using H2O-NaI as the Electrolyte Solution at Room Temperature
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With H2O as the solvent and NaI as the supporting electrolyte, a green and efficient electrochemical route has been developed to synthesize arylsulfonamides via I2electrogenerated in situ at a graphite anode to promote the reaction of sodium sulfinates with aromatic or aliphatic primary and secondary amines. The target products could be obtained in good to excellent yields at room temperature.
- Zhang, Chen,Chen, Yibin,Yuan, Gaoqing
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p. 1277 - 1282
(2016/12/27)
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- Electrochemical Oxidative Amination of Sodium Sulfinates: Synthesis of Sulfonamides Mediated by NH4I as a Redox Catalyst
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An efficient protocol for the synthesis of sulfonamides via the electrochemical oxidative amination of sodium sulfinates has been developed. The chemistry proceeds in a simple undivided cell employing a substoichiometric amount of NH4I that serves both as a redox catalyst and a supporting electrolyte; in this manner additional conducting salt is not required. A wide range of substrates, including aliphatic or aromatic secondary and primary amines, as well as aqueous ammonia, proved to be compatible with the protocol. Scale-up was possible, thereby demonstrating the practicality of the approach. The electrolytic process avoids the utilization of external oxidants or corrosive molecular iodine and therefore represents an environmentally benign means by which to achieve the transformation.
- Jiang, Yang-Ye,Wang, Qing-Qing,Liang, Sen,Hu, Li-Ming,Little, R. Daniel,Zeng, Cheng-Chu
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p. 4713 - 4719
(2016/07/06)
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- Synthesis of sulfonamides: Via copper-catalyzed oxidative C-N bond cleavage of tertiary amines
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A copper-catalyzed coupling reaction of sulfonyl chlorides with tertiary amines via the oxidative C-N bond cleavage of tertiary amines was developed. Sulfonamides were synthesized using this strategy in moderate to good yields. The reaction was applicable to various tertiary amines, as well as sulfonyl chlorides.
- Ji, Jing,Liu, Zhengyi,Liu, Ping,Sun, Peipei
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p. 7018 - 7023
(2016/07/30)
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- Synthesis of sulfonamides via I2-mediated reaction of sodium sulfinates with amines in an aqueous medium at room temperature
-
An efficient I2-mediated approach for the synthesis of sulfonamides at room temperature using water as the solvent has been developed. This method for the synthesis of sulfonamides is quite convenient and environmentally friendly. In addition, the purification procedure of the desired products becomes very easy. This journal is
- Pan, Xiaojun,Gao, Jian,Liu, Juan,Lai, Junyi,Jiang, Huanfeng,Yuan, Gaoqing
-
supporting information
p. 1400 - 1403
(2015/03/18)
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- Metal-free oxidative coupling of amines with sodium sulfinates: A mild access to sulfonamides
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A practical and mild procedure for the preparation of sulfonamides through TBAI-catalyzed oxidative coupling of amines with sodium sulfinates using TBHP as an oxidant was presented. A variety of amines and sodium sulfinates could go through the transformation, without impacting the hydroxyl group. This journal is
- Zhao, Jinwu,Xu, Jingxiu,Chen, Jiaxi,Wang, Xiaoqin,He, Minghua
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p. 64698 - 64701
(2015/04/27)
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- Palladium-catalyzed intramolecular oxidative coupling involving double C(sp2)-H bonds for the synthesis of annulated biaryl sultams
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The palladium-catalyzed intramolecular oxidative coupling described herein involves a double C(sp2)-H bond functionalization in sulfonanilides, providing a workable access to biaryl sultams annulated into a six-membered ring that are otherwise difficult to obtain by literature methods. The other synthetic applications of this protocol including the synthesis of biaryl sultams containing a seven-membered ring and analogous sultones are also presented.
- Laha, Joydev K.,Jethava, Krupal P.,Dayal, Neetu
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p. 8010 - 8019
(2015/03/18)
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- Flow synthesis and biological activity of aryl sulfonamides as selective carbonic anhydrase IX and XII inhibitors
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A series of secondary and tertiary aryl sulfonamides were synthesized under flow conditions and evaluated for their ability to selectively inhibit tumor-associated carbonic anhydrase isoforms IX and XII. The tested compounds revealed to be highly potent CA IX inhibitors in nanomolar range, and to inhibit CA XII activity with different ranks of potencies. Remarkably, 4-methyl-N-phenyl-benzenesulfonamide was a selective nanomolar CA IX inhibitor with an IC50 of 90 nM.
- Rosatelli, Emiliano,Carotti, Andrea,Ceruso, Mariangela,Supuran, Claudiu T.,Gioiello, Antimo
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supporting information
p. 3422 - 3425
(2014/07/22)
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- Copper-catalyzed sulfonamides formation from sodium sulfinates and amines
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A new and convenient method for the construction of sulfonamides via a copper-catalyzed oxidative coupling between sodium sulfinates and amines with 1 atm O2 or DMSO as the oxidant was described. This method provides efficient and robust synthesis of functional sulfonamides in good yields and excellent chemoselectivity. And detailed mechanistic studies showed that this transformation may go through a single electron transfer (SET) pathway.
- Tang, Xiaodong,Huang, Liangbin,Qi, Chaorong,Wu, Xia,Wu, Wanqing,Jiang, Huanfeng
-
supporting information
p. 6102 - 6104
(2013/07/11)
-
- Building a sulfonamide library by eco-friendly flow synthesis
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A rapid and eco-friendly synthesis of a sulfonamide library under flow conditions is described. The study illustrates an efficient, safe, and easily scalable preparation of sulfonamides by use of a meso-reactor apparatus, thus demonstrating the impact of flow technologies within drug discovery. Waste minimization, employment of green media, and nontoxic reactants are achieved by the optimization of the flow setup and experimental protocol designed to sequentially synthesize primary, secondary, and tertiary sulfonamides. Isolation of the products involves only extraction and precipitation affording pure compounds in good to high yields without further purification for biological evaluation.
- Gioiello, Antimo,Rosatelli, Emiliano,Teofrasti, Michela,Filipponi, Paolo,Pellicciari, Roberto
-
supporting information
p. 235 - 239
(2013/06/27)
-
- Gold-catalyzed intermolecular [4+2] and [2+2+2] cycloadditions of ynamides with alkenes
-
As good as gold: Gold-catalyzed intermolecular [4+2] cycloadditions of 2-arylynamides with alkenes and gold-catalyzed [2+2+2] cycloadditions of terminal ynamides with enol ethers have been developed (see scheme). The [4+2] cycloaddition is compatible with a range of alkenes and arylynamides and the [2+2+2] cycloaddition can also accommodate a variety of different arylynamide and enol ether substrates.
- Dateer, Ramesh B.,Shaibu, Balagopal S.,Liu, Rai-Shung
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supporting information; experimental part
p. 113 - 117
(2012/02/16)
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- Cs2CO3 catalyzed rapid and efficient conversion of amines into sulfonamides; Alcohols and phenols into sulfonic esters
-
A simple and efficient method has been developed for the sulfonylation of several amines, alcohols, and phenols by p-toluenesulphonylchloride (p-TsCl) in the presence of catalytic amount of Cs2CO3 at 25C to obtain sulfonamides and sulfonic esters in very good yields. Cs2CO3 has been found to be highly efficient catalyst. Taylor & Francis Group, LLC.
- Reddy, M. B. Madhusudana,Pasha
-
experimental part
p. 1867 - 1875
(2011/10/11)
-
- METHOD FOR DEPROTECTING ARYL OR ALKYL SULFONAMIDES OF PRIMARY OR SECONDARY AMINES
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The invention relates to a method for removing an alkyl sulfonyl or aryl sulfonyl protecting group from a primary or secondary amine by contacting an alkyl sulfonamide or an aryl sulfonamide with a Stage 0 or Stage I alkali metal-silica gel material in the presence of a solid proton source under conditions sufficient to form the corresponding amine. The invention also relates to a method for removing an alkyl sulfonyl or aryl sulfonyl protecting group from a primary or secondary amine by a) reacting an alkyl sulfonamide or an aryl sulfonamide with a Stage 0 or Stage I alkali metal-silica gel material, and b) subsequently reacting the reaction product from step a) with an electrophile or a proton source. Preferred Stage 0 or Stage I alkali metal-silica gel materials include Na, K2Na, and Na2K.
- -
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Page/Page column 7
(2009/12/24)
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- Alkali metals in silica gel (M-SG): A new reagent for desulfonation of amines
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(Chemical Equation Presented) A novel method for the desulfonation of secondary amines is described. Alkali metals absorbed into nanostructured silica (M-SG) were found to be useful solid-state reagents for the desuffonation of a range of N,N-disubstituted sulfonamides. M-SG reagents are room-temperature- stable free-flowing powders that retain the chemical reactivity of the parent metal, decreasing the danger and associated cost of using reactive metals.
- Nandi, Partha,Redko, Mikhail Y.,Petersen, Kathryn,Dye, James L.,Lefenfeld, Michael,Vogt, Paul F.,Jackson, James E.
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supporting information; experimental part
p. 5441 - 5444
(2009/06/18)
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- Trichlorophenol (TCP) sulfonate esters: A selective alternative to pentafluorophenol (PFP) esters and sulfonyl chlorides for the preparation of sulfonamides
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2,4,6-Trichlorophenol (TCP) sulfonate esters undergo effective aminolysis under conventional heating and microwave irradiation; the reactivity of these species is such that chemoselective transformations of PFP sulfonate esters can be achieved. The Royal Society of Chemistry.
- Wilden, Jonathan D.,Geldeard, Lynsey,Lee, Chieh C.,Judd, Duncan B.,Caddick, Stephen
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p. 1074 - 1076
(2007/12/29)
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- Facile N-arylation of amines and sulfonamides and O-arylation of phenols and arenecarboxylic acids
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An efficient, transition-metal-free procedure for the N-arylation of amines, sulfonamides, and carbamates and O-arylation of phenols and carboxylic acids has been achieved by allowing these substrates to react with a variety of o-silylaryl inflates in the presence of CsF. Good to excellent yields of arylated products are obtained under very mild reaction conditions. This chemistry readily tolerates a variety of functional groups.
- Liu, Zhijian,Larock, Richard C.
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p. 3198 - 3209
(2007/10/03)
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- Organometallic chemistry of amidate complexes. Accelerating effect of bidentate ligands on the reductive elimination of N-aryl amidates from palladium(II)
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We report a series of arylpalladium complexes of acetamidate, sulfonamidate, and deprotonated oxazolidinone ligands that undergo reductive elimination with rates and yields that depend on the binding mode of the ancillary and amidate ligands. Complexes of the acetamidate ligands containing the bidentate phosphines DPPF and Xantphos as ancillary ligands undergo reductive elimination. The rate and yield were higher from the complex ligated by Xantphos, which contains a larger bite angle. In contrast, the analogous amidate complex containing a single sterically hindered monodentate ligand and a κ2-bound amidate ligand does not undergo reductive elimination. This trend of faster reductive elimination from complexes containing bidentate ancillary ligands than from a complex with a single monodentate ancillary ligand is unusual and is consistent with an effect of the denticity of the ancillary ligand on the binding mode of the amidate. Complexes of sulfonamidate ligands underwent reductive elimination faster than complexes of acetamidates, and reductive elimination occurred from complexes containing both bidentate and monodentate ancillary ligands. Like reductive elimination from the acetamidate complexes, reductive eliminations from the sulfonamidate complexes were faster when the complexes possessed bidentate Xantphos and κ1-sulfonamidate ligands. Copyright
- Fujita, Ken-Ichi,Yamashita, Makoto,Puschmann, Florian,Alvarez-Falcon, Miguel Martinez,Incarvito, Christopher D.,Hartwig, John F.
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p. 9044 - 9045
(2007/10/03)
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- Palladium-catalyzed alkylation-hydride reduction sequence: Synthesis of meta-substituted arenes
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(Chemical Equation Presented) A new three-component, palladium-catalyzed domino reaction which gives access to meta-substituted arenes using aryl iodides and primary alkyl halides is reported. Various functional groups are tolerated on both the aryl iodide and alkyl halide. In addition, isotopic labeling studies provide insight into the mechanism of this Catellani-type reaction.
- Wilhelm, Thorsten,Lautens, Mark
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p. 4053 - 4056
(2007/10/03)
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- Facile N-Arylation of Amines and Sulfonamides
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(Matrix presented) A facile, transition-metal-free N-arylation procedure for amines and sulfonamides has been developed, which affords good to excellent yields of arylated products under very mild reaction conditions. A methoxy-substituted aryl triflate affords N-arylated products in high yields with excellent regioselectivity. This chemistry tolerates a variety of functional groups.
- Liu, Zhijian,Larock, Richard C.
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p. 4673 - 4675
(2007/10/03)
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- Photo-Fries rearrangement of N-arylsulfonamides to aminoaryl sulfone derivatives
-
Photochemical reaction of variously substituted p-toluenesulfonanilides was studied. The reaction gives rearranged products, o- and p-amino-substituted diaryl sulfones with the combined yields of 38-72%: the p-isomer is more favored over the o-isomer with the selectivity ratio of 1.1-4.3 depending on the substituents. N-Alkylation of the sulfonanilides increases the yields of the rearranged products, and e-withdrawing substituents on the N-phenyl ring does not lower the yields drastically. This study provides simple methodology for the synthesis of o- and p-aminoaryl sulfones which are otherwise not easily accessible.
- Park, Kwanghee Koh,Lee, Jin Joo,Ryu, Jaegyung
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p. 7651 - 7659
(2007/10/03)
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- A facile route to the deprotection of sulfonate esters and sulfonamides with low valent titanium reagents
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A novel method for the cleavage of N/O-tosyl bonds by low-valent titanium is reported. TBDPS ether, THP ether, and olefin are found to be compatible under the reaction conditions.
- Nayak
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p. 1575 - 1578
(2007/10/03)
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- Promotion of reaction of N-H bonds with triarylbismuth and cupric acetate
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Arylation of a diverse group of N-H containing compounds at room temperature with triarylbismuth and cupric acetate in the presence of a tertiary amine promoter, such as triethylamine or pyridine, is described. This mild and highly efficient procedure, which is based on Barton's earlier work on the arylation of amines, can be applied to amides, imides, ureas, carbamates, and sulfonamides. Copyright (C) 1996 Elsevier Science Ltd.
- Chan, Dominic M. T.
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p. 9013 - 9016
(2007/10/03)
-
- Stereospecific synthesis of secondary amines by the Mitsunobu reaction
-
A facile synthesis of secondary amines from alcohols is reported with N-methyltrifluoromethanesulfonamide (2) in the Mitsunobu reaction. The reaction was demonstrated to proceed with inversion of configuration and provided a convenient synthetic route to
- Edwards,Stemerick,McCarthy
-
p. 3417 - 3420
(2007/10/02)
-
- Pseudomolecular Rearrangement of O-Ethyl N-Methyl Toluene-4-sulphonimidate to N-Ethyl-N-methyltoluene-4-sulphonamide and its Relevance to the Nucleophilic Properties of Neutral Sulphonamides
-
Kinetic studies are reported for the pseudo-molecular rearrangement of O-ethyl N-methyl toluene-4-sulphonimidate to N-ethyl-N-methyltoluene-4-sulphonamide in organic solvents at 34-100 deg C.Without catalysts, the rearrangement follows the equation rate = krearr 2, which is indicative of an intermolecular SN2 transalkylation via an ion-pair intermediate: it is accompained by concurrent E2 elimination to N-methyltoluene-4-sulphonamide.The rearrangement is catalysed by electrophilic reagents such as alkyl halides, ZnI2, and HBr where rate = k2 .For alkyl halides, a two-step mechanism via an ionic intermediate applies in which formation of the intermediate by an SN2 reaction between the substrate and alkyl halide is rate limiting.Other catalysts effect rearrangement by forming alkyl halides in an initial rapid reaction with the substrate.The results are discussed in relation to the ambident nucleophilic properties of sulphonamides.It is suggested that, like carboxylic acid amides and phosphinylamides, alkylation occurs most readily at the O-atom of neutral sulphonamides to give a sulphonimidate (kinetic product), which then rearranges in the presence of electrophilic catalysts to give an N-substituted sulphonamide (thermodynamic product).Rearrangement is normally too fast for the isolation of O-alkyl sulphonimidates, but O-aryl analogues can be obtained.
- Challis, Brian C.,Iley, James N.
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p. 699 - 704
(2007/10/02)
-