- Synthesis of (±)-pterocarpin and its thia- and aza-analogues in a modular manner
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Syntheses of racemic pterocarpin, its thia- and aza-pterocarpin have been achieved in a modular manner using sesamol iodide, diethyl malonate and 3-methoxyphenol, 3-methoxythiophenol and N-tosyl-3-methoxyaniline as building blocks. Copper-mediated Hurtley
- Huang, Qingyun,Wang, Peng,Tian, Yu,Song, Ni,Ren, Sumei,Tao, Jiaxin,Hang, Kaini,Li, Ming
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Read Online
- Corrigendum to “Transition-metal-free synthesis of aromatic amines via the reaction of benzynes with isocyanates” [Tetrahedron Lett. 59 (2018) 671–674](S0040403918300352)(10.1016/j.tetlet.2018.01.022)
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The authors regret that the structure of Scheme 3 is shown incorrectly. The structure of the compound 3e' is shown correctly here.[Figure presented] The penultimate paragraph of the “Results and Discussion” section should read as follows: During the investigation of several substrates, we observed the unexpected product 3e' which had a diphenyl backbone with a tosyl amine in 45% yield (Scheme 3). This structure was confirmed by 1H NMR, 13C NMR, and high-resolution mass spectroscopy. The diphenyl scaffold is useful to develop new ligands, or synthesize materials, pharmaceuticals, and natural products.The Authors also note corrections needed to the data of compound 3j in the Supplementary Data files. This should be re-written as follows: 13C NMR (125 MHz, CDCl3) δ 150.4 (dd, 1C, JC–F = 242.8, 8.2 Hz), 148.3 (dd, 1C, JC–F = 240.6, 7.3 Hz), 144.4, 135.6, 133.0 (dd, 1C JC–F = 8.1, 3.3 Hz), 129.9, 127.3, 118.1 (q, 1C, JC-F = 3.3 Hz), 117.8 (dd, 1C, JC–F = 18.2, 1.3 Hz), 111.8 (d, 1C, JC–F = 20.3 Hz), 21.6.The updated Supplementary Data files have been published online with this Corrigendum. The authors would like to apologise for any inconvenience caused.
- Seo, Jeong Hoon,Ko, Haye Min
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supporting information
p. 1213 - 1213
(2019/03/23)
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- Characteristic Hydrogen Bonding Observed in the Crystals of Aromatic Sulfonamides: 1D Chain Assembly of Molecules and Chiral Discrimination on Crystallization
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N-Phenylbenzenesulfonamides exist preferentially in (+)- or (-)-synclinal conformations, which place the aromatic rings at both ends in the same direction with a twist. We have systematically analyzed the crystal structure of secondary aromatic sulfonamides bearing methyl, ethyl, and/or methoxy groups on the benzene rings. Intermolecular hydrogen bonding between the sulfonamide protons and sulfonyl oxygens was observed in 81 out of 85 crystals. The intermolecular hydrogen-bonding patterns could be classified into four types, i.e. Dimeric, Zigzag, Helical, and Straight patterns, with retention of the synclinal conformation of the sulfonamide moiety. We investigated the relationship between the hydrogen-bonding pattern and the proportion of the compounds that show chiral crystallization. On the basis of our classification of the intermolecular hydrogen bonds of aromatic sulfonamides, the crystals with Dimeric and Zigzag patterns, which both have enantiomeric synclinal conformers, intrinsically become achiral, except for kryptoracemates. In contrast, a high proportion of compounds with Helical or Straight patterns in the crystals showed chiral crystallization. Our classification is useful for discussion regarding the chirality of molecular assemblies, on the basis of the conformational chirality of the molecules in the crystal.
- Kikkawa, Shoko,Masu, Hyuma,Katagiri, Kosuke,Okayasu, Misaki,Yamaguchi, Kentaro,Danjo, Hiroshi,Kawahata, Masatoshi,Tominaga, Masahide,Sei, Yoshihisa,Hikawa, Hidemasa,Azumaya, Isao
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p. 2936 - 2946
(2019/05/10)
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- Facile Chan-Lam coupling using ferrocene tethered N-heterocyclic carbene-copper complex anchored on graphene
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Ferrocene tethered N-heterocyclic carbene-copper complex anchored on graphene ([GrFemImi]NHC@Cu complex) has been synthesized by covalent grafting of ferrocenyl ionic liquid in the matrix of graphene followed by metallation with copper (I) iodide. The [GrFemImi]NHC@Cu complex has been characterized by fourier transform infrared (FT-IR), fourier transform Raman (FT-Raman), CP-MAS 13C NMR spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), energy dispersive X-ray (EDX) analysis, X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface area analysis and X-ray diffractometer (XRD) analysis. This novel complex served as a robust heterogeneous catalyst for the synthesis of bioactive N-aryl sulfonamides from variety of aryl boronic acids and sulfonyl azides in ethanol by Chan-Lam coupling. Recyclability experiments were executed successfully for six consecutive runs.
- Gajare, Shivanand,Jagadale, Megha,Naikwade, Altafhusen,Bansode, Prakash,Rashinkar, Gajanan
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- Transition-metal-free synthesis of aromatic amines via the reaction of benzynes with isocyanates
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An unexpected reaction between benzynes and isocyanates to generate aromatic amines has been developed under transition-metal-free conditions. The in situ prepared anions formed through cleavage of the N–C bond in isocyanates, reacted with aryne precursor
- Seo, Jeong Hoon,Ko, Haye Min
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supporting information
p. 671 - 674
(2018/01/19)
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- Triple Mode of Alkylation with Ethyl Bromodifluoroacetate: N, or O-Difluoromethylation, N-Ethylation and S-(ethoxycarbonyl)difluoromethylation
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In this report, we have explored a triple mode of chemical reactivity of ethyl bromodifluoroacetate. Typically, bromodifluoroacetic acid has been used as a difluorocarbene precursor for difluoromethylation of soft nucleophiles. Here we have disclosed nucleophilicity and base dependent divergent chemical reactivity of ethyl bromodifluoroacetate. It furnishes lithium hydroxide and cesium carbonate promoted difluoromethylation of tosyl-protected aniline and electron-deficient phenols respectively. Interestingly, switching the base from lithium hydroxide to 4-N,N-dimethylamino pyridine (DMAP) tosyl-protected anilines afforded the corresponding N-ethylation product. Whereas, highly nucleophilic thiophenols furnished the corresponding S-carboethoxydifluoromethylation product via a rapid SN2 attack to the bromine atom prior to the ester hydrolysis. This mechanistic divergence was established through several control experiments. It was revealed that difluoromethylation reaction proceeds through a tandem in situ ester hydrolysis/decarboxylative-debrominative difluorocarbene formation and subsequent trapping by the soft nucleophile-NHTs or electron-deficient phenolic ?OH groups. In the presence of DMAP the hydrolysis of the ester is perturbed instead a nucleophilic attack at the ethyl moiety provides the N-ethylation product. Hence, besides the development of a practical base-promoted N-difluoromethylation of amines and electron-deficient phenols, divergent reactivity pattern of inexpensive and user-friendly ethyl bromodifluoroacetate has been explored. (Figure presented.).
- Polley, Arghya,Bairy, Gurupada,Das, Pritha,Jana, Ranjan
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supporting information
p. 4161 - 4167
(2018/09/21)
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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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supporting information
p. 6636 - 6640
(2017/05/29)
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- Discovery, Optimization, and Biological Evaluation of Sulfonamidoacetamides as an Inducer of Axon Regeneration
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Axon regeneration after injury in the central nervous system is hampered in part because if an age-dependent decline in the intrinsic axon growth potential, and one of the strategies to stimulate axon growth in injured neurons involves pharmacological manipulation of implicated signaling pathways. Here we report phenotypic cell-based screen of chemical libraries and structure-activity-guided optimization that resulted in the identification of compound 7p which promotes neurite outgrowth of cultured primary neurons derived from the hippocampus, cerebral cortex, and retina. In an animal model of optic nerve injury, compound 7p was shown to induce growth of GAP-43 positive axons, indicating that the in vitro neurite outgrowth activity of compound 7p translates into stimulation of axon regeneration in vivo. Further optimization of compound 7p and elucidation of the mechanisms by which it elicits axon regeneration in vivo will provide a rational basis for future efforts to enhance treatment strategies.
- Ku, Jin-Mo,Park, Kyuhee,Lee, Jung Hun,Cho, Kyong Jin,Nam, Yeon-Ju,Jeong, Dae-Youn,Kim, Yu-Han,Kwon, Soonjung,Park, Ju-Young,Yang, Jungeun,Nam, Tae-Gyu,Yoon, Sung-Hwa,Ahn, Sangmee,Choi, Yongmun
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p. 4676 - 4687
(2016/06/13)
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- A highly efficient heterogeneous copper-catalyzed Chan-Lam coupling reaction of sulfonyl azides with arylboronic acids leading to: N -arylsulfonamides
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A heterogeneous Chan-Lam coupling reaction between sulfonyl azides and arylboronic acids was achieved in MeOH at room temperature in the presence of 10 mol% of an l-proline-functionalized MCM-41-immobilized copper(i) complex [MCM-41-l-proline-CuCl] under air, yielding a variety of N-arylsulfonamides in excellent yields. The new heterogeneous copper complex can be prepared from commercially readily available and inexpensive reagents, and recovered by simple filtration of the reaction solution and recycled at least 8 times without any decreases in activity.
- You, Chongren,Yao, Fang,Yan, Tao,Cai, Mingzhong
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p. 43605 - 43612
(2016/05/24)
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- Nickel-catalyzed monoarylation of ammonia
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Structurally diverse (hetero)aryl chloride, bromide, and tosylate electrophiles were employed in the Ni-catalyzed monoarylation of ammonia, including chemoselective transformations. The employed JosiPhos/[Ni(cod)2] catalyst system enables the use of commercially available stock solutions of ammonia, or the use of ammonia gas in these reactions, thereby demonstrating the versatility and potential scalability of the reported protocol. Proof-of-principle experiments established that air-stable [(JosiPhos)NiCl2] precatalysts can be employed successfully in such transformations. Lighten Up: The substrate scope of the title reaction includes (hetero)aryl chloride, bromide, and tosylate electrophiles. The versatility and potential scalability of the reported method is demonstrated by the use of either commercially available stock solutions of ammonia or ammonia gas.
- Borzenko, Andrey,Rotta-Loria, Nicolas L.,Macqueen, Preston M.,Lavoie, Christopher M.,McDonald, Robert,Stradiotto, Mark
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supporting information
p. 3773 - 3777
(2015/03/18)
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- Direct C-H amidation of benzoic acids to introduce meta- and para-amino groups by tandem decarboxylation
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The Ir-catalyzed mild C-H amidation of benzoic acids with sulfonyl azides was developed to give reactions with high efficiency and functional-group compatibility. Subsequent protodecarboxylation of ortho-amidated benzoic acid products afforded meta- or para-substituted (N-sulfonyl)aniline derivatives, the latter being inaccessible by other C-H functionalization approaches. The decarboxylation step was compatible with the amidation conditions, enabling a convenient one-pot, two-step process. Without a trace: Carboxylic acids are used as traceless directing groups in the Ir-catalyzed direct C-H amidation of arenes with sulfonyl azides under mild conditions. The tandem protodecarboxylation of the ortho-amidated benzoic acid products afforded meta- or para-substituted (N-sulfonyl)anilines, which are difficult to obtain by other C-H functionalization approaches.
- Lee, Donggun,Chang, Sukbok
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p. 5364 - 5368
(2015/03/30)
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- Synthesis of phenyl-1-benzoxepinols isolated from butcher's broom and analogous benzoxepines
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Extracts of Ruscus aculeatus L., known as butcher's broom, are mainly used for the treatment of chronic venous insufficiency (CVI). In a recent study on the phenolic compounds of Rusci rhizoma, new phenyl-1-benzoxepinols were isolated. As the therapeutic effect of butcher's broom is ascribed to the pharmacological activity of the main constituents, steroidal saponins and their aglycones the ruscogenins, the role of the newly identified compounds was of interest. Owing to the low availability of the compounds by isolation, we synthesized them for pharmacological testing. In an ORAC-fluorescein assay they revealed a significant antioxidative activity, which may contribute to the anti-inflammatory properties of the phenolic fraction obtained from Rusci rhizoma extracts. Copyright
- Herrmann, Josef M.,Untergehrer, Monika,Juergenliemk, Guido,Heilmann, Joerg,Koenig, Burkhard
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supporting information
p. 3170 - 3181
(2014/06/09)
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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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- Copper-catalyzed mild nitration of protected anilines
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A practical copper-catalyzed direct nitration of protected anilines, by using one equivalent of nitric acid as the nitrating agent, has been developed. This procedure features mild reaction conditions, wide structural scope (with regard to both N-protecting group and arene substitution), and high functional-group tolerance. Dinitration with two equivalents of nitric acid is also feasible. Practical and reliable: A Cu-catalyzed selective nitration of para- and ortho-substituted aniline derivatives by using one equivalent of HNO3 has been developed that produces water as the only stoichiometric byproduct (see scheme; PG=protecting group). This method is compatible with strongly electron-deficient substrates, enabling dinitration (by using 2.0 equiv of HNO3). This method allows for a rapid access to relevant nitrogen-containing heterocyclic architectures.
- Hernando, Elier,Castillo, Rafael R.,Rodríguez, Nuria,G?mez Arrayás, Ram?n,Carretero, Juan C.
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supporting information
p. 13854 - 13859
(2016/02/18)
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- Copper-catalyzed Chan-Lam Coupling between Sulfonyl Azides and Boronic acids at room temperature
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A mild and efficient method for the synthesis of N-arylsulfonamides in the presence of 10 mol % of CuCl is demonstrated. The reaction proceeds readily at room temperature in an open flask using a variety of sulfonyl azides and boronic acids without any base, ligand, or additive.
- Moon, Soo-Yeon,Nam, Jungsoo,Rathwell, Kris,Kim, Won-Suk
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supporting information
p. 338 - 341
(2014/04/03)
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- Efficient ligand-free, copper-catalyzed N-arylation of sulfonamides
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An efficient and convenient protocol has been developed for the N-arylation of sulfonamides with differently substituted aryl iodides using ligand-free copper iodide to afford the arylated products in good to excellent yields (up to 91%). Georg Thieme Verlag Stuttgart.
- Teo, Yong-Chua,Yong, Fui-Fong
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supporting information; experimental part
p. 837 - 843
(2011/06/21)
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- Intramolecular catalytic Friedel-Crafts reactions with allenyl cations for the synthesis of quinolines and their analogues
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(Equation Presented) This paper describes a novel method to synthesize a quinoline backbone by incorporating allenyl cations into a catalytic intramolecular Friedel-Crafts reaction. The initial products were isomerized and aromatized upon treatment with acid and base, respectively, to give quinolines. The basic concept also proved to be promising for 1-benzazepine, 1-benzazocine, or isoquinoline synthesis.
- Ishikawa, Teruhiko,Manabe, Shinobu,Aikawa, Toshiaki,Kudo, Takayuki,Saito, Seiki
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p. 2361 - 2364
(2007/10/03)
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- Pd-catalyzed intermolecular amidation of aryl halides: The discovery that xantphos can be trans-chelating in a palladium complex
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A general method for the intermolecular coupling of aryl halides and amides using a Xantphos/ Pd catalyst is described. This system displays good functional group compatibility, and the desired C-N bond forming process proceeds in good to excellent yields with 1-4 mol % of the Pd catalyst. Additionally, the arylation of sulfonamides, oxazolidinones, and ureas is reported. The efficiency of these transformations was found to be highly dependent on reaction concentrations and catalyst loadings. A Pd complex resulting from oxidative addition of 4-bromobenzonitrile, (Xantphos)Pd(4-cyanophenyl)(Br) (II), was prepared in one step from Xantphos, Pd2(dba)3, and the aryl bromide. Complex II proved to be an active catalyst for the coupling between 4-bromobenzonitrile and benzamide. X-ray crystallographic analysis of II revealed a rare trans-chelating bisphosphine-Pd(II) structure with a large bite angle of 150.7°.
- Yin, Jingjun,Buchwald, Stephen L.
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p. 6043 - 6048
(2007/10/03)
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- A practical route to quinolines from anilines
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A practical route to quinoline from anilines through acid-mediated cyclization of 3-(N-aryl-N-sulfonylamino)propionaldehydes has been developed. Treatment of the cyclization products, dihydroquinoline intermediates with KOH in DMSO leads to substituted quinolines.
- Tokuyama, Hidetoshi,Sato, Masashi,Ueda, Toshihiro,Fukuyama, Tohru
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p. 105 - 108
(2007/10/03)
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- Solid phase synthesis of sulfonamides using a carbamate linker
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A method for the synthesis of sulfonamides on a solid support by immobilizing amines through the nitrogen atom using a carbamate linkage is described.
- Raju,Kogan, Timothy P.
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p. 3373 - 3376
(2007/10/03)
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- AMEBA: An acid sensitive aldehyde resin for solid phase synthesis
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Oxidation of 4-(3-methoxy-4-hydroxymethylphenoxy)methyl polystyrene resin produced AMEBA resin 1, a novel acid sensitive aldehyde resin. Reductive amination of AMEBA resin generated resin bound amines which were derivatized as sulfonamides, amides, ureas, and carbamates. Cleavage of the resin under mild acidic conditions generated the derivatized amines in high purity and moderate yield.
- Fivush, Adam M.,Willson, Timothy M.
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p. 7151 - 7154
(2007/10/03)
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- Stereoselective syntheses of substituted pterocarpans with anti-HIV activity, and 5-aza-/5-thia-pterocarpan and 2-aryl-2,3-dihydrobenzofuran analogues
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Oxygenated pterocarpans and 5-azapterocarpans are prepared utilizing Lewis acid-promoted reactions of 2-alkoxy-1,4-benzoquinones with 2H-chromenes and N-tosyl-1,2-dihydroquinolines, respectively. Similarly, benzannulated analogues are prepared via reactions of 5-aIkoxy-1,4-naphthoquinones with chromenes, and related 2-aryl-2,3-dihydrobenzofurans result from reactions of styrenes with the quinones. Syntheses of 5-thiapterocarpans are also described utilizing Pd(0)-coupling of o-chloromercuriophenols with 2H-chromenes.
- Engler, Thomas A.,LaTessa, Kenneth O.,Iyengar, Rajesh,Chai, Wenying,Agrios, Konstantinos
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p. 1755 - 1769
(2007/10/03)
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- Cycloaddition reactions of 1,4-benzoquinone mono- And bisimides with styrenyl systems: New syntheses of nitrogen substituted azapterocarpans, pterocarpans, 2-aryl-2,3-dihydroindoles and -dihydrobenzofurans
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Lewis acid-promoted reactions of 1,4-benzoquinones and 1,4-benzoquinone bis- and monoimides with various 2H-chromenes, N-tosyl-1,2-dihydroquinolines and styrenes regio- and stereoselectively produce the title compounds in good yields.
- Engler, Thomas A.
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p. 2713 - 2716
(2007/10/02)
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- Studies in Antifertility Agents: Part XXVII - Synthesis of 2-Acetyl-3-aryl-5-tosyl-7/8-H (or methoxy)-3,3a,4,5-tetrahydropyrazoloquinolines
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N-Tosyl-2,3-dihydro-4-quinolones (12-14), prepared from aniline, m- and p-anisidines by reported procedures, on condensation with araldehydes in the presence of NaOMe give the corresponding 3-arylidene-4-quinolones (15-18).Refluxing of 15-18 with NH2-NH2*H2O in gl.AcOH affords the title compounds, 2-acetyl-3-aryl-5-tosyl-7/8-H (or methoxy)-3,3a,4,5-tetrahydropyrazoloquinolines (19-22).The stereochemistry of the title compounds based on the assignments of C3-H, C3a-H, C4-H2 protons has been studied by PMR decoupling experiments.In preliminary screening, compounds 19 and 22 have been found to prevent pregnancy at 20 mg/kg dose in female albino rats, but are ineffective at lower doses.None of the compounds tested shows any significant pharmacological activity.
- Kelkar, Prabhakar M.,Sangwan, Naresh K.,Rastogi, Shri Nivas,Anand, Nitya
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p. 297 - 300
(2007/10/02)
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