- Micellar Effects in the Acid Denitrosation of N-Nitroso-N-methyl-p-toluenesulfonamide
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The acid denitrosation of N-methyl-N-nitroso-p-toluenesulfonamide (MNTS) has been studied in the presence of anionic, cationic, and nonionic surfactants.Both cationic and nonionic micelles inhibit the reaction through an effective association of the substrate to the micellar pseudophase.This bound substrate becomes unreactive due to the absence of protons in the micellar Stern layer.The kinetic results allow a quantitative estimation of the association constants.The reaction has also been studied in the presence of anionic surfactants, both functionalized and nonfunctionalized.With hydrogen dodecyl sulfate, the reaction is accelerated by the presence of surfactant and reaches a limiting value at high concentrations.The reaction with sodium dodecyl sulfate shows a familiar pattern of behavior, with the reactivity passing through a maximum as the concentration of surfactant is increased.These facts can be quantitatively understood in terms of the pseudophase ion-exchange model, assuming a constancy in the degree of micellar fraction charge neutralized.Numerical values for the rate constants in the micellar pseudophase could be obtained and compared with those in water.Association constants between MNTS and micellar aggregates can also be obtained as well as the equilibrium exchange constants between Na+ and protons.The study of the system in the presence of added NaCl, KCl, and CsCl provided further test for the kinetic model as well as the estimation of other ion-exchange constants.
- Bravo, Carlos,Herves, Pablo,Leis, J. Ramon,Pena, M. Elena
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- Ligand-Controlled Regiodivergence for Catalytic Stereoselective Semireduction of Allenamides
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Ligand-controlled regiodivergence has been developed for catalytic semireduction of allenamides with excellent chemo- and stereocontrol. This system also provides an example of catalytic regiodivergent semireduction of allenes for the first time. The divergence of the semireduction is enabled by ligand switch with the same palladium pre-catalyst under operationally simple and mild conditions. Monodentate ligand XPhos exclusively promotes selective 1,2-semireduction to afford allylic amides, while bidentate ligand BINAP completely switched the regioselectivity to 2,3-semireduction, producing (E)-enamide derivatives.
- Hajiloo Shayegan, Mojtaba,Li, Zhong-Yuan,Cui, Xin
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supporting information
(2021/12/02)
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- Chemoselective Cleavage of Acylsulfonamides and Sulfonamides by Aluminum Halides
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The chemoselective cleavage of C-N bonds of amides, sulfonamides, and acylsulfonamides by aluminum halides is described. AlCl3and AlI3display complementary reactivities toward N-alkyl and N-acyl moieties. N-Alkylacylsulfonamides, sec
- Sang, Dayong,Dong, Bingqian,Liu, Yunfeng,Tian, Juan
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p. 3586 - 3595
(2022/02/25)
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- Visible-Light-Induced C4-Selective Functionalization of Pyridinium Salts with Cyclopropanols
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The site-selective C?H functionalization of heteroarenes is of considerable importance for streamlining the rapid modification of bioactive molecules. Herein, we report a general strategy for visible-light-induced β-carbonyl alkylation at the C4 position of pyridines with high site selectivity using various cyclopropanols and N-amidopyridinium salts. In this process, hydrogen-atom transfer between the generated sulfonamidyl radicals and O?H bonds of cyclopropanols generates β-carbonyl radicals, providing efficient access to synthetically valuable β-pyridylated (aryl)ketones, aldehydes, and esters with broad functional-group tolerance. In addition, the mild method serves as an effective tool for the site-selective late-stage functionalization of complex and medicinally relevant molecules.
- Hong, Sungwoo,Kim, Taehwan,Vellakkaran, Mari
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supporting information
(2021/11/27)
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- N-Aroylsulfonamide-Photofragmentation (ASAP)-A Versatile Route to Biaryls
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The photochemical fragmentation of N-aroylsulfonamides 9 (ASAP) is a powerful method for the preparation of various biaryls. Compounds 9 are easily accessible in two steps from amines by treatment with arenesulfonyl chlorides and aroyl chlorides. Many of these compounds were prepared for the first time. The irradiation takes place in a previously developed continuous-flow reactor using inexpensive UVB or UVC fluorescent lamps. Isocyanates and sulphur dioxide are formed as the only by-products. The ASAP tolerates a variety of functional groups and is even suited for the preparation of phenylnaphthalenes and terphenyls. The ASAP mechanism was elucidated by interaction of photophysical and quantum chemical (DFT) methods and revealed a spirocyclic biradical as key intermediate.
- Wessig, Pablo,Krebs, Saskia
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supporting information
p. 6367 - 6374
(2021/09/29)
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- Electrochemical C?H Amidation of Heteroarenes with N-Alkyl Sulfonamides in Aqueous Medium
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The construction of C?N bonds by free radical reactions represents a powerful synthetic approach for direct C?H amidations of arenes or heteroarenes. Developing efficient and more environmentally friendly synthetic methods for C?H amidation reactions remains highly desirable. Herein, metal-free electrochemical oxidative dehydrogenative C?H amidations of heteroarenes with N-alkylsulfonamides have been accomplished. The catalyst- and chemical-oxidant-free C?H amidation features an ample scope and employs electricity as the green and sole oxidant. A variety of heteroarenes, including indoles, pyrroles, benzofuran and benzothiophene, thereby underwent this C(sp2)?H nitrogenation. Cyclic voltammetry studies and control experiments provided evidence for nitrogen-centered radicals being directly generated under metal-free electrocatalysis.
- Zhang, Yan,Lin, Zhipeng,Ackermann, Lutz
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supporting information
p. 242 - 246
(2020/11/30)
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- Cobalt-Catalyzed 1,4-Aryl Migration/Desulfonylation Cascade: Synthesis of α-Aryl Amides
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A cobalt-catalyzed 1,4-aryl migration/disulfonylation cascade applied to α-bromo N-sulfonyl amides was developed. The reaction was highly chemoselective, allowing the preparation of α-aryl amides possessing a variety of functional groups. The method was used as the key step to synthesize an alkaloid, (±)-deoxyeseroline. Mechanistic investigations suggest a radical process.
- Gillaizeau-Simonian, Nicolas,Barde, Etienne,Guérinot, Amandine,Cossy, Janine
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supporting information
p. 4004 - 4008
(2021/02/11)
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- Chemoselective Electrosynthesis Using Rapid Alternating Polarity
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Challenges in the selective manipulation of functional groups (chemoselectivity) in organic synthesis have historically been overcome either by using reagents/catalysts that tunably interact with a substrate or through modification to shield undesired sites of reactivity (protecting groups). Although electrochemistry offers precise redox control to achieve unique chemoselectivity, this approach often becomes challenging in the presence of multiple redox-active functionalities. Historically, electrosynthesis has been performed almost solely by using direct current (DC). In contrast, applying alternating current (AC) has been known to change reaction outcomes considerably on an analytical scale but has rarely been strategically exploited for use in complex preparative organic synthesis. Here we show how a square waveform employed to deliver electric current - rapid alternating polarity (rAP) - enables control over reaction outcomes in the chemoselective reduction of carbonyl compounds, one of the most widely used reaction manifolds. The reactivity observed cannot be recapitulated using DC electrolysis or chemical reagents. The synthetic value brought by this new method for controlling chemoselectivity is vividly demonstrated in the context of classical reactivity problems such as chiral auxiliary removal and cutting-edge medicinal chemistry topics such as the synthesis of PROTACs.
- Baran, Phil S.,Carlson, Ethan,Edwards, Jacob T.,Hayashi, Kyohei,Kawamata, Yu,Saito, Masato,Shaji, Shobin,Simmons, Bryan J.,Waldmann, Dirk,Zapf, Christoph W.
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supporting information
p. 16580 - 16588
(2021/10/20)
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- Nickel/Photoredox Dual Catalytic Cross-Coupling of Alkyl and Amidyl Radicals to Construct C(sp3)-N Bonds
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The construction of C(sp3)-N bonds via direct radical-radical cross-coupling under benign conditions is a desirable but challenging approach. Herein, the cross-coupling of alkyl and amidyl radicals to build aliphatic C-N bonds in a concise, mild, and oxid
- Zhou, Shaofang,Lv, Kang,Fu, Rui,Zhu, Changlei,Bao, Xiaoguang
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p. 5026 - 5034
(2021/05/07)
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- Copper-catalyzed oxidative methylation of sulfonamides by dicumyl peroxide
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A novel and facile copper-catalyzed methylation of sulfonamides was herein demonstrated. The practical transformation took place readily under the oxidative conditions, and N-methyl amides (23 examples) were successfully furnished in high efficiency (up to 90% yields). Dicumyl peroxide was considered to act not only as the oxidant in the system, but also methyl donor for the methylation protocol.
- Che, Shiying,Zhu, Qiao,Luo, Zhenghong,Lian, Yan,Zhao, Zijian
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p. 935 - 942
(2021/01/05)
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- Recyclable covalent triazine framework-supported iridium catalyst for the N-methylation of amines with methanol in the presence of carbonate
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An iridium complex Cp*Ir@CTF, which is synthesized by the coordinative immobilization of [Cp*IrCl2]2 on a functionalized covalent triazine framework (CTF), was found to be a general and highly efficient catalyst for the N-methylation of amines with methanol in the presence of carbonate. Under environmentally benign conditions, a variety of desirable products were obtained in high yields with complete selectivities and functional group friendliness. Furthermore, the synthesized catalyst could be recycled by simple filtration without obvious loss of catalytic activity after sixth cycle. Notably, this research exhibited the potential of covalent triazine framework-supported transition metal catalysts for hydrogen autotransfer process.
- Liu, Peng,Yang, Jiazhi,Ai, Yao,Hao, Shushu,Chen, Xiaozhong,Li, Feng
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p. 281 - 290
(2021/03/26)
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- N-Methylation of Amines with Methanol in the Presence of Carbonate Salt Catalyzed by a Metal-Ligand Bifunctional Ruthenium Catalyst [(p-cymene)Ru(2,2′-bpyO)(H2O)]
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A ruthenium complex [(p-cymene)Ru(2,2′-bpyO)(H2O)] was found to be a general and efficient catalyst for the N-methylation of amines with methanol in the presence of carbonate salt. Moreover, a series of sensitive substituents, such as nitro, ester, cyano, and vinyl groups, were tolerated under present conditions. It was confirmed that OH units in the ligand are crucial for the catalytic activity. Notably, this research exhibited the potential of metal-ligand bifunctional ruthenium catalysts for the hydrogen autotransfer process.
- Liu, Peng,Tung, Nguyen Thanh,Xu, Xiangchao,Yang, Jiazhi,Li, Feng
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p. 2621 - 2631
(2021/02/27)
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- Additive-freeN-methylation of amines with methanol over supported iridium catalyst
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An efficient and versatile zinc oxide-supported iridium (Ir/ZnO) catalyst was developed to catalyze the additive-freeN-methylation of amines with methanol. Mechanistic studies suggested that the high catalytic reactivity is rooted in the small sizes (1.4 nm) of Ir nanoparticles and the high ratio (93%) of oxidized iridium species (IrOx, Ir3+and Ir4+) on the catalyst. Moreover, the delicate cooperation between the IrOxand ZnO support also promoted its high reactivity. The selectivity of this catalyticN-methylation was controllable between dimethylation and monomethylation by carefully tuning the catalyst loading and reaction solvent. Specifically, neat methanol with high catalyst loading (2 mol% Ir) favored the formation ofN,N-dimethylated amine, while the mesitylene/methanol mixture with low catalyst loading (0.5 mol% Ir) was prone to producing mono-N-methylated amines. An environmentally benign continuous flow system with a recycled mode was also developed for the efficient production ofN-methylated amines. With optimal flow rates and amine concentrations, a variety ofN-methylamines were produced with good to excellent yields in this Ir/ZnO-based flow system, providing a starting point for the clean and efficient production ofN-methylamines with this cost-effective chemical process.
- Liu, Xiang,Loh, Teck-Peng,Qiang, Wenwen,Wang, Jing,Ye, Sen,Zhu, Longfei
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p. 3364 - 3375
(2021/06/06)
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- Direct Introduction of Sulfonamide Groups into Quinoxalin-2(1H)-ones by Cu-Catalyzed C3-H Functionalization
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Direct sulfonamidation of quinoxalin-2(1H)-one derivatives has been developed using a readily available Cu salt as the catalyst and inexpensive ammonium persulfate as the oxidant in moderate conditions. Owing to the feature of handy operation and good functional group tolerance, this method provides a convenient and efficient access to curative 3-sulfonamidated quinoxalin-2(1H)-one scaffolds.
- Tan, Yushi,Liu, Boyan,Han, Ya-Ping,Zhang, Yuecheng,Zhang, Hong-Yu,Zhao, Jiquan
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supporting information
p. 3365 - 3369
(2020/10/02)
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- Electrophilic Cyanative Alkenylation of Arenes
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A variety of appropriately substituted internal alkynes were transformed into the corresponding cyano-substituted phenanthrenes, dihydronaphthalenes, and cyclohepta-1,3,5-trienes in moderate to excellent yields by treatment with imidazolium thiocyanate 1, which serves as an easy to handle [CN]+ precursor, in the presence of BCl3. The synthetic value of the method is additionally demonstrated by the transformation of the primarily obtained products into heavily substituted quinolines. Additionally, the dynamic properties of the prepared dibenzocyclohepta-1,3,5-trienes have been investigated.
- Zhao, Mingyue,Barrado, Alejandro G.,Sprenger, Kristin,Golz, Christopher,Mata, Ricardo A.,Alcarazo, Manuel
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supporting information
p. 4932 - 4937
(2020/06/08)
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- Electron Transfer Photoredox Catalysis: Development of a Photoactivated Reductive Desulfonylation of an Aza-Heteroaromatic Ring
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Herein, we report a protocol for desulfonylation of aza-heteroaromatic rings via photoinduced electron transfer and hydrogen atom transfer. This general protocol has a wide substrate range and moderate to good yields. The utility of the method was demonstrated by the chemoselective desulfonylation of a molecule containing both an aliphatic and an aromatic sulfonamide. (Figure presented.).
- Qiang-Liu,Liu, Yu-Xiu,Song, Hong-Jian,Wang, Qing-Min
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supporting information
p. 3110 - 3115
(2020/07/04)
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- Facile one-pot synthesis of 2-aminoindoles from simple anilines and ynamides
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A highly effective and straightforward one-pot synthesis of diversely substituted 2-aminoindoles has been developed, involving sequential Au(i)-catalyzed regioselective hydroamination and CuCl2-mediated oxidative cyclization. This protocol offers an operationally easy, simple, robust, and sustainable approach with the use of readily available starting materials, good functional group tolerance, and high practicality and efficiency. This journal is
- Kim, Young Ho,Yoo, Huen Ji,Youn, So Won
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supporting information
p. 13963 - 13966
(2020/11/20)
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- Dealkoxylation ofN-alkoxyamides without an external reductant driven by Pd/Al cooperative catalysis
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Lewis acid-assisted palladium-catalysed dealkoxylation ofN-alkoxyamides has been developed. This reaction proceeded smoothly with a range ofN-alkoxyamides in the absence of an external reductant, thereby establishing a convenient and reductant-free protocol. In addition, a gram-scale reaction could be achieved. Preliminary mechanistic investigations indicated that β-hydrogen elimination from a palladium alkoxide intermediate generated an intramolecular hydride source.
- Suzuki, Hirotsugu,Shiomi, Takahiro,Yoneoka, Kenji,Matsuda, Takanori
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supporting information
p. 7545 - 7548
(2020/10/15)
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- Method for synthesizing N-methyl sulfonamide in water
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The invention discloses a method N - for synthesizing,methylsulfamide in water, by using a transition metal iridium catalyst to catalyze N - methylation reaction. by using a non-toxic and harmless water as a solvent, to avoid using the organic agent; to react only as a byproduct, without an environmental hazard; reaction temperature with respect to the previous strip more mild; and have a wide application prospect; with high selectivity, reaction atomic economy.
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Paragraph 0030-0034
(2020/03/12)
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- N-Methylation of Amines with Methanol in Aqueous Solution Catalyzed by a Water-Soluble Metal-Ligand Bifunctional Dinuclear Iridium Catalyst
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The N-methylation of amines with methanol in aqueous solution was proposed and accomplished by using a water-soluble metal-ligand bifunctional dinuclear iridium catalyst. In the presence of [(Cp*IrCl)2(thbpym)][Cl]2 (1 mol %), a range of desirable products were obtained in high yields under environmentally benign conditions. Notably, this research exhibited the potential of transition metal-catalyzed activation of methanol as a C1 source for the construction of the C-N bond in aqueous solution.
- Han, Xingyou,Li, Feng,Liu, Peng,Meng, Chong,Tung, Nguyen Thanh
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p. 5815 - 5824
(2020/05/26)
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- Bimetallic Bis-NHC-Ir(III) Complex Bearing 2-Arylbenzo[d]oxazolyl Ligand: Synthesis, Catalysis, and Bimetallic Effects
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Herein, an unprecedented bimetallic bis-NHC Cp*Ir complex 1 bearing 2-arylbenzo[d]oxazolyl and NHC ligands is reported. A significant increase in activity was observed for N-methylation of amines and reduction of aldehydes with MeOH catalyzed by 1 compared to the monometallic analogues (2-11). Under the optimal conditions, it showed to be highly effective in N-methylation of nitroarenes with MeOH as both C1 and H2 source. Substrates, including aromatic amines, ketones, and nitro compounds with various functional groups, can be well-tolerated. Mechanistic studies and DFT calculation highlight the significance of bimetallic centers cooperativity.
- Huang, Shuang,Hong, Xi,Cui, He-Zhen,Zhan, Bing,Li, Zhi-Ming,Hou, Xiu-Feng
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p. 3514 - 3523
(2020/10/09)
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- A Micellar Catalysis Strategy for Amidation of Alkynyl Bromides: Synthesis of Ynamides in Water
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Copper-catalyzed amidation of alkynyl bromides can be carried out in water for the first time, which is made possible by a micellar catalysis strategy using rosin-based surfactant APGS-550-M. The surfactant can be easily prepared from natural abundant biomass, resin acids. Studies as to substrate scope and reaction aqueous medium recycling showcase the ease and sustainability of this technology.
- Yang, Yunqin,Meng, Xiangtai,Zhu, Baolong,Jia, Ying,Cao, Xiaoji,Huang, Shenlin
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supporting information
p. 1166 - 1169
(2019/01/04)
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- Transition-Metal-Free One-Step Synthesis of Ynamides
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A robust transition-metal-free one-step strategy for the synthesis of ynamides from sulfonamides and (Z)-1,2-dichloroalkenes or alkynyl chlorides is presented. This method is not only effective for internal ynamides but also amenable for terminal ynamides. Various functional groups, even the vinyl moiety, are compatible, and thus, this strategy offers the opportunity for further functionalization.
- Zeng, Xianzhu,Tu, Yongliang,Zhang, Zhenming,You, Changming,Wu, Jiao,Ye, Zhiying,Zhao, Junfeng
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p. 4458 - 4466
(2019/03/26)
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- C(sp3)-H Bond Arylation and Amidation of Si-Bound Methyl Group via Directing Group Strategy
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Silylmethyl functionalization provides a general and efficient access to diverse organosilanes. The traditional methods for silylmethyl functionalization often involved silylmethylmetals or silylmethylhalides. In recent years, a C-H activation strategy has become one of the most attractive alternatives in organic synthesis. We envisioned that the attachment of a coordinating group at silicon of methylsilanes provides the opportunity to modify the silylmethyl group via directed C-H bond functionalization. However, despite employment of silicon tethers bearing a directing group (DG) for C(sp2)-H functionalization has been well established due to the fact that the silicon tethers are easily installable and removable/modifiable, applying this concept toward C(sp3)-H functionalization remains underdeveloped. Herein, we successfully develop IrIII/RhIII-catalyzed C-H bond arylation/amidation of silyl methyl group by using directing group strategy, which constitutes the most powerful access to benzylsilanes and amino-substituted silanes. Moreover, we demonstrated that the pyridine directing group on silicon atom can be easily removed, and the starting materials can also be efficiently recovered, which are different from those of pyridine-directed C-H functionalization of C-bound methyl group.
- Han, Jie-Lian,Qin, Ying,Zhao, Dongbing
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p. 6020 - 6026
(2019/06/25)
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- N -Methylation of ortho -substituted aromatic amines with methanol catalyzed by 2-arylbenzo [d] oxazole NHC-Ir(iii) complexes
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Seven new chelated cyclometalated Ir complexes of ABON,P, ABON,O, and ABON,C(carbene) based on a rigid and tunable 2-arylbenzo[d]oxazole backbone have been prepared for the N-methylation of amines. Among these three coordinated modes, ABON,C(carbene)-chelated iridium-based catalysts exhibited good performance in the monomethylation of aromatic amines with methanol (MeOH) as the green methylation reagent. The steric-modified synthesis of ABON,C(carbene) complexes was described. The most active ABON,C(carbene) complex with marginal steric hindrance as a catalyst was obtained from the benzoxazole ring without a substituent and methyl group of the benzimidazole ring on the N-heterocyclic carbene (NHC) ligand. A variety of amines including para- and meta-substituted aromatic amines, as well as heterocyclic amines, were formulated as suitable substrates. Importantly, this catalyst considerably promoted the yield of the N-methylation of ortho-substituted aromatic amines. Controlled kinetic experiments and deuterium-labeling reactions of these ortho-substituted amines were conducted under optimized conditions. On the basis of the experimental results, a plausible mechanism was proposed.
- Huang, Shuang,Hong, Xi,Cui, He-Zhen,Zhou, Quan,Lin, Yue-Jian,Hou, Xiu-Feng
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p. 5072 - 5082
(2019/04/17)
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- Manganese-Catalyzed N-Alkylation of Sulfonamides Using Alcohols
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An efficient manganese-catalyzed N-alkylation of sulfonamides has been developed. This borrowing hydrogen approach employs a well-defined and bench-stable Mn(I) PNP pincer precatalyst, allowing benzylic and simple primary aliphatic alcohols to be employed as alkylating agents. A diverse range of aryl and alkyl sulfonamides undergoes mono-N-alkylation in excellent isolated yields (32 examples, 85% average yield).
- Reed-Berendt, Benjamin G.,Morrill, Louis C.
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p. 3715 - 3724
(2019/03/30)
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- Synthesis of 3-Amino-1-benzothiophene-1,1-diones by Alkyne Directed Hydroarylation and 1/N→3/C-Sulfonyl Migration
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A completely regioselective and highly stereoselective palladium-catalyzed intramolecular hydroarylation of arenesulfonyl ynamines to benzothiazoles was developed. The presence of an electron-withdrawing group on the triple bond of the sulfonyl ynamine was crucial for the success of the reaction and our mechanistic studies suggest an alkyne-directed 5-exo-dig cyclization pathway. The products easily underwent photoinduced rearrangement to 3-amino-1-benzothiophene-1,1-diones (up to 35 % yields after two steps).
- Bernar, Ivan,Blanco-Ania, Daniel,Stok, Sophie J.,Sotorríos, Lia,Gómez-Bengoa, Enrique,Rutjes, Floris P. J. T.
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supporting information
p. 5435 - 5444
(2018/10/20)
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- Visible light mediated oxidation of benzylic sp3 C-H bonds using catalytic 1,4-hydroquinone, or its biorenewable glucoside, arbutin, as a pre-oxidant
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Benzylic ethers undergo a visible light induced C-H activation and oxygen insertion to give the corresponding benzoate esters in moderate to good yields. The conditions employ substoichiometric amounts of 1,4-hydroquinone with copper(ii) chloride dihydrate as an electron-transfer mediator, oxygen as the terminal oxidant and dimethyl carbonate as solvent under visible light irradiation. The naturally occurring glucoside, arbutin, which is commercially available or can be accessed via extraction of the leaves of bearberry (Arctostaphylos uva-ursi) or elephant ears (Bergenia crassifolia) can be used as a biorenewable source of 1,4-hydroquinone. The methodology exploits the increase in oxidizing ability of quinones upon irradiation with visible light, and offers a sustainable alternative for the late stage oxidative functionalization of benzylic C-H bonds. It is applicable to a range of cyclic benzylic ethers such as isochromans and phthalans, and simple benzyl alkyl ethers. It can also be applied in the oxidation of benzylic amines into amides, and of diarylmethanes into the corresponding ketones. Mechanistic studies suggest that the reaction proceeds by H-abstraction by the photo-excited triplet benzoquinone to give a benzylic radical that subsequently reacts with molecular oxygen.
- Finney, Laura C.,Mitchell, Lorna J.,Moody, Christopher J.
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supporting information
p. 2242 - 2249
(2018/05/28)
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- Three-Component Ring-Opening Reactions of Cyclic Ethers, α-Diazo Esters, and Weak Nucleophiles under Metal-Free Conditions
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A protocol for three-component reactions of cyclic ethers, α-diazo esters, and weak nitrogen, oxygen, carbon, and sulfur nucleophiles (pKa = 2.2-14.8) to afford a variety of structurally complex α-oxyalkylated esters is reported. These reactions involve intermolecular activation of the cyclic ether (present in excess) by the α-diazo ester to form an oxonium ylide under metal-free conditions, followed by ring opening by the nucleophile.
- Lu, Lin,Chen, Chuwei,Jiang, Huanfeng,Yin, Biaolin
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p. 14385 - 14395
(2018/11/27)
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- Silver(i)-catalyzed sequential hydroamination and Prins type cyclization for the synthesis of fused benzo-δ-sultams
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An intramolecular annulation strategy has been developed for the synthesis of tetrahydrobenzo[e]pyrano[4,3-c][1,2]thiazine derivatives by means of coupling of aldehydes with 2-(4-hydroxybut-1-yn-1-yl)-N-arylsulfonamides using a catalytic amount of silver hexafluoroantimonate in toluene at 80 °C. This is the first report on the synthesis of fused benzo-δ-sultam derivatives through C-N, C-O, and C-C bond formations. The reaction proceeds through a cascade of hydroamination and Prins type cyclization.
- Maheshwar Rao,Yadav,Sridhar,Subba Reddy
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supporting information
p. 5163 - 5166
(2018/07/29)
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- Highly efficient synthesis of aryl ketones by PEPPSI-palladium catalyzed acylative Suzuki coupling of amides with diarylborinic acids
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An improved acylative cross-coupling of various N-methyl-N-tosyl amides with diarylborinic acids for synthesis of aryl ketones is developed. In most cases, aryl ketones could be obtained in excellent yields by using 1 mol% 2,6-diisopropylphenylimidazolylidene and 3-chloropyridine co-supported palladium chloride as catalyst in the presence of 3 equiv. K2CO3 as base in refluxing THF. The readily prepared and cost-effective substrates, N-methyl-N-tosylamides and diarylborinic acids, and the commercially available catalyst system promise a practical and efficient access to aryl ketones.
- Wang, Chen,Huang, Lingyun,Wang, Fengze,Zou, Gang
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supporting information
p. 2299 - 2301
(2018/05/16)
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- Copper(i)-catalyzed N-H olefination of sulfonamides for: N -sulfonyl enaminone synthesis
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This communication reports copper-catalyzed N-H olefination of sulfonamides for enaminone synthesis using saturated ketones as olefin sources. With TEMPO derivatives and O2 as oxidants, this method provided an efficient way to produce various enaminones in good yields. Mechanistic studies helped figure out the stable intermediates and develop novel methodologies for the difunctionalization of saturated ketones.
- Liang, Xiao,Huang, Xin,Xiong, Mingteng,Shen, Kexin,Pan, Yuanjiang
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supporting information
p. 8403 - 8406
(2018/08/03)
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- Methylation of Amines and Ketones with Methanol Catalyzed by an Iridium Complex Bearing a 2-Hydroxypyridylmethylene Fragment
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Reaction of complex [Cp?Ir(HOC5H3CH2C5H3OH)Cl][Cl] (1) with AgOTf generated the product [Cp?Ir(HOC5H3CH2C5H3OH)(H2O)][OTf]2 (2), which was further transformed to the complex [Cp?Ir(OC5H3CH2C5H3O)(H2O)] (3) in the presence of t-BuONa via -OH deprotonation. Complexes 1-3 exhibited high activity for the methylation of amines and ketones. These C-C and C-N coupling reactions proceeded in air with 1 mol % catalyst loading in the presence of K2CO3.
- Deng, Danfeng,Hu, Bowen,Yang, Min,Chen, Dafa
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p. 3353 - 3359
(2018/09/25)
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- Iron-Catalyzed Methylation Using the Borrowing Hydrogen Approach
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A general iron-catalyzed methylation has been developed using methanol as a C1 building block. This borrowing hydrogen approach employs a Kn?lker-type (cyclopentadienone)iron carbonyl complex as catalyst (2 mol %) and exhibits a broad reaction scope. A variety of ketones, indoles, oxindoles, amines, and sulfonamides undergo mono- or dimethylation in excellent isolated yields (>60 examples, 79% average yield).
- Polidano, Kurt,Allen, Benjamin D. W.,Williams, Jonathan M. J.,Morrill, Louis C.
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p. 6440 - 6445
(2018/07/25)
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- Selective synthesis of mono- and di-methylated amines using methanol and sodium azide as C1 and N1 sources
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A Ru(ii) complex mediated synthesis of various N,N-dimethyl and N-monomethyl amines from organic azides using methanol as a methylating agent is reported. This methodology was successfully applied for a one-pot reaction of bromide derivatives and sodium azide in methanol. Notably, by controlling the reaction time several N-monomethylated and N,N-dimethylated amines were synthesized selectively. The practical applicability of this tandem process was revealed by preparative scale reactions with different organic azides and synthesis of an anti-vertigo drug betahistine. Several kinetic experiments and DFT studies were carried out to understand the mechanism of this transformation.
- Chakrabarti, Kaushik,Mishra, Anju,Panja, Dibyajyoti,Paul, Bhaskar,Kundu, Sabuj
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supporting information
p. 3339 - 3345
(2018/07/29)
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- Targeted Polypharmacology: Discovery of a Highly Potent Non-Hydroxamate Dual Matrix Metalloproteinase (MMP)-10/-13 Inhibitor
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Matrix metalloproteinases (MMPs) play a key role in many diseases like cancer, atherosclerosis or arthritis. Interest in MMP inhibition has been revitalized very recently as the knowledge on the underlying network of biological pathways is steadily growing. On the basis of this new insight into the relevance of MMP-10 and MMP-13 within the MMP network and the ban of hydroxamate inhibitors from clinical development, the discovery of non-hydroxamate multitarget drugs against specific MMPs is of foremost interest. Here, we disclose the discovery of a very potent and selective non-hydroxamate MMP-10/-13 inhibitor. The high potency (IC50 of 31 nM [MMP-10] and 5 nM [MMP-13]) and selectivity over MMP-1, -2, -3, -7, -8, -9, -12, and -14 enable this compound to decipher disease causing MMP networks and to generate new treatment options through targeted polypharmacology.
- Senn, Nicole,Ott, Michael,Lanz, Jan,Riedl, Rainer
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p. 9585 - 9598
(2017/12/26)
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- The scope and regioselectivity of intramolecular N-C rearrangements of orthogonally protected sulfonamides, including cyclization to saccharin derivatives
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The scope and regiochemistry of the intramolecular N-C rearrangement involving ortholithiation of orthogonally protected sulfonamides in which an N-acyl or N-carboalkoxy group is transferred from nitrogen to the aromatic ring have been explored. Provided that excess lithium diisopropylamide is used, the process is compatible with the presence of acidic α-protons in a substituent attached to the aromatic ring or if the protons in the migrating acyl group are relatively inaccessible because of steric factors. In certain cases, the isolated product is not the ortho carboalkoxy species, but the derived saccharin; the regiochemistry found for starting materials containing a naphthalene ring is consistent with ortho lithiation at the most electron deficient position.
- Saidykhan, Amie,Ebert, Jenessa,Ally, Hashim,Gallagher, Richard T.,Martin, William H.C.,Bowen, Richard D.
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supporting information
p. 3089 - 3091
(2017/07/18)
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- Copper-Catalyzed Arylsulfonylation and Cyclizative Carbonation of N-(Arylsulfonyl)acrylamides Involving Desulfonative Arrangement toward Sulfonated Oxindoles
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Sulfonated oxindoles are accessed by a Cu(OAc)2-catalyzed three-component reaction of N-(arylsulfonyl)acrylamides, DABSO, and aryldiazonium tetrafluoroborates. This transformation is triggered by the formation of arylsulfonyl radicals in situ from the reaction of aryldiazonium tetrafluoroborates and DABSO. Afterward, the sequential radical addition, radical cyclization, and desulfonylative 1,4-aryl migration take place to provide the final product by the formation of four new bonds in one pot. This procedure shows good functional group tolerance.
- Wang, Hepan,Sun, Song,Cheng, Jiang
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supporting information
p. 5844 - 5847
(2017/11/10)
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- Mono-N-methylation of anilines with methanol catalyzed by a manganese pincer-complex
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The selective mono-N-methylation of anilines derivatives was achieved under mild conditions using inexpensive methanol as C1 source. Under hydrogen borrowing conditions, using a tridentate PN3P manganese pre-catalyst (5?mol%), a catalytic amount of base (20?mol%), for 24?h at 120?°C, a large variety of anilines derivatives was methylated in good to excellent yield. Mechanistic investigations allowed us to isolate and characterize by X-ray diffraction studies a de-aromatized manganese intermediate.
- Bruneau-Voisine, Antoine,Wang, Ding,Dorcet, Vincent,Roisnel, Thierry,Darcel, Christophe,Sortais, Jean-Baptiste
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- N-Methylation of Amines with Methanol Catalyzed by a Cp?Ir Complex Bearing a Functional 2,2′-Bibenzimidazole Ligand
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A new type of Cp?Ir complex bearing a functional 2,2′-bibenzimidazole ligand was designed, synthesized, and found to be a highly effective and general catalyst for the N-methylation of a variety of amines with methanol in the presence of a weak base (0.3 equiv of Cs2CO3).
- Liang, Ran,Li, Shun,Wang, Rongzhou,Lu, Lei,Li, Feng
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supporting information
p. 5790 - 5793
(2017/11/10)
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- Studies on the Synthesis of the Alkaloid (-)-Gilbertine via Indolidene Chemistry
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A synthesis route to the pentacyclic alkaloid (-)-gilbertine, which features a cyclization cascade passing through a transient indolidene intermediate, was pursued. A key stereochemical relationship was set via a Nicholas-type enolate alkylation. Ultimately, undesired C-N cyclization thwarted the final projected C-C bond forming ring closure, and gilbertine could not be prepared by this route.
- Feldman, Ken S.,Folda, Tamara S.
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supporting information
p. 4566 - 4575
(2016/07/06)
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- UV Light Induced Direct Synthesis of Phenanthrene Derivatives from a Linear 3-Aryl-N-(arylsulfonyl) Propiolamides
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A novel photochemical approach for the synthesis of phenanthrene derivatives from linear 3-aryl-N-(arylsulfonyl) propiolamides via a tandem radical Smiles rearrangement/C-S bonding/Mallory reaction is disclosed. The control experiment results and isolation of the key intermediates give further insight into the reaction mechanism. Gram scale reaction using a flow reactor demonstrated the synthetic potential applications of our protocol.
- Chen, Ming,Yang, Chao,Wang, Yanpei,Li, Dazhi,Xia, Wujiong
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supporting information
p. 2280 - 2283
(2016/06/01)
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- The mechanism of alkene elimination from protonated toluenesulphonamides generated by electrospray ionisation
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The positive ion electrospray mass spectra of a range of sulphonamides of general structure CH3C6H4SO2NHR1 [R1 = CnH2n+1 (n = 1-7), CnH2n-1 (n = 3, 4), C6H5, C6H5CH2 and C6H5CH(CH3)] and CH3C6H4SO2NR1R2 [R1, R2 = CnH2n+1 (n = 1-8)] are reported and discussed. The protonated sulphonamides derived from saturated primary and secondary aliphatic amines generally fragment to only a limited extent unless energised by collision. Two general fragmentations are observed: firstly, elimination of an alkene, CnH2n, obtained by hydrogen abstraction from one of the CnH2n+1 alkyl groups on nitrogen; secondly, cleavage to form CH3C6H4SO2+. The mechanism by which an alkene is lost has been probed by studying the variation of the intensity of the [M + H - CnH2n]+ signal with the structure of the alkyl substituent(s) on nitrogen and by monitoring the competition between the loss of different alkenes from protonated unsymmetrical sulphonamides in which two different alkyl groups are attached to nitrogen. This fragmentation is favoured by branching of the alkyl group at the carbon atom directly attached to nitrogen, thus suggesting that it involves a mechanism in which the stability of the cation obtained by stretching the bond connecting the nitrogen atom to the alkyl group is critical. This interpretation also explains the competition between alkene elimination and cleavage to form CH3C6H4SO2+ (and, in some cases, cleavage to form C6H5CH2+ or [C6H5CHCH3]+).
- Saidykhan, Amie,Ebert, Jenessa,Martin, William H.C.,Gallagher, Richard T.,Bowen, Richard D.
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p. 165 - 173
(2016/11/09)
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- Electrochemical synthesis of sulfonamides from arenesulfonohydrazides or sodium p-methylbenzenesulfinate and amines
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An efficient electrochemical synthesis of sulfonamides (yields 56–98%) from arenesulfonohydrazides or sodium p-methylbenzenesulfinate and amines was performed in an undivided cell with graphite anode and iron cathode in MeCN–H2O medium using halides as redox mediators and supporting electrolytes.
- Terent'ev, Alexander O.,Mulina, Olga M.,Pirgach, Dmitry A.,Syroeshkin, Mikhail A.,Glinushkin, Alexey P.,Nikishin, Gennady I.
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p. 538 - 539
(2016/12/02)
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- Alkylation of Sulfonamides with Trichloroacetimidates under Thermal Conditions
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An intermolecular alkylation of sulfonamides with trichloroacetimidates is reported. This transformation does not require an exogenous acid, base, or transition metal catalyst; instead the addition occurs in refluxing toluene without additives. The sulfonamide alkylation partner appears to be only limited by sterics, with unsubstituted sulfonamides providing better yields than more encumbered N-alkyl sulfonamides. The trichloroacetimidate alkylating agent must be a stable cation precursor for the substitution reaction to proceed under these conditions.
- Wallach, Daniel R.,Chisholm, John D.
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p. 8035 - 8042
(2016/09/12)
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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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- Regioselective Access to Sultam Motifs through Cobalt-Catalyzed Annulation of Aryl Sulfonamides and Alkynes using an 8-Aminoquinoline Directing Group
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The use of cobalt as catalyst in direct C-H activation protocols as a replacement for more expensive second row transition metals is currently attracting significant attention. Herein we disclose a facile cobalt-catalyzed C-H functionalization route towards sultam motifs through annulation of easily prepared aryl sulfonamides and alkynes using 8-aminoquinoline as a directing group. The reaction shows broad substrate scope with products obtained in a highly regioselective manner in good to excellent isolated yields. Mechanistic insights suggest the formation of a Co(III)-aryl key species via a rate-determining arene C-H activation during the annulation reaction.
- Planas, Oriol,Whiteoak, Christopher J.,Company, Anna,Ribas, Xavi
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supporting information
p. 4003 - 4012
(2016/01/25)
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- NRF2 REGULATORS
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The present invention relates to bis aryl analogs, pharmaceutical compositions containing them and their use as Nrf2 regulators.
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Page/Page column 136
(2015/07/07)
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- Palladium-Catalyzed Regio- and Chemoselective Reactions of 2-Bromobenzyl Bromides: Expanding the Scope for the Synthesis of Biaryls Fused to a Seven-Membered Sultam
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Speedy access to biaryls fused to seven-membered sultams was achieved by starting from readily accessible N-alkylbenzenesulfonamides and 2-bromobenzyl bromides. The protocol features a domino reaction and proceeds through an N-benzylation followed by an intramolecular direct C-H arylation that occurs ortho to the sulfonamide group. A palladium-catalyzed domino reaction of N-alkylbenzenesulfonamides and 2-bromobenzyl bromides gives biaryls fused to a seven-membered sultam. This approach employs readily accessible substrates and provides speedy access to fused-ring compounds.
- Laha, Joydev K.,Sharma, Shubhra,Dayal, Neetu
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p. 7885 - 7891
(2015/12/24)
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- Synthesis and characterization of biocompatible bimodal meso-sulfonamide-perfluorophenylporphyrins
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Herein we describe a synthetic strategy for preparing a set of meso-aryl sulfonamide-perfluorinated porphyrins by covalent binding in order to obtain new chemical entities that can potentially target bacteria and act both as bacteriostatic and photosensitizing agents. The conditions optimized allow to selectively obtain porphyrins containing the desired number of sulfonamide substituents. The new compounds showed a broad range of 1-octanol/water partition coefficients and singlet oxygen quantum yields from 0.59 to 0.74. Our results demonstrate that sulfonamide-perfluorinated porphyrins are a promising platform for biomedical applications, particularly in aPDT and medical imaging.
- Vinagreiro, Carolina S.,Gon?alves, Nuno P.F.,Calvete, Mário J.F.,Schaberle, Fábio A.,Arnaut, Luís G.,Pereira, Mariette M.
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p. 161 - 167
(2015/10/12)
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- Synthesis of sulfonamides via I2-mediated reaction of sodium sulfinates with amines in an aqueous medium at room temperature
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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
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supporting information
p. 1400 - 1403
(2015/03/18)
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