- Stereoselective Synthesis of Pyrroloquinolines by a Br?nsted Acid Catalyzed [4+2]-Heterocyclization of Indole-7-Carbaldehydes, Anilines and Electron-Rich Alkenes
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The pyrrolo[3,2,1-ij]quinoline heterocyclic core is found in the structure of a variety of compounds with interesting applications and then, new efficient and flexible strategies to construct this skeleton are required. Here, a new diastereoselective tetrafluoroboric acid (HBF4)-catalyzed three-component coupling reaction of 1H-indole-7-carbaldehyde derivatives, anilines and electron-rich alkenes to give pyrrolo[3,2,1-ij]quinolines is described. The reaction involves an unusual [4+2]-heterocyclization between an in situ formed imine and an alkene. The new catalytic method, where water is the only by-product, is efficient, robust and flexible, and allows for multigram-scale synthesis.
- Galván, Alicia,Fontaneda, Raquel,Fa?anás, Francisco J.,Rodríguez, Félix
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- Synthesis, molecular docking studies, and larvicidal activity evaluation of new fluorinated neonicotinoids against Anopheles darlingi larvae
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Anopheles darlingi is the main vector of malaria in Brazil, characterized by a high level of anthropophilia and endophagy. Imidacloprid, thiacloprid, and acetamiprid are the most widespread insecticides of the neonicotinoid group. However, they produce adverse effects on the non-target insects. Flupyradifurone has been marketed as an alternative to non-fluorinated neonicotinoids. Neonicotinoids containing trifluoroacethyl substituent reveal increased insecticidal activity due to higher hydrophobicity and metabolic stability. We synthesized novel neonicotinoid insecticides containing fluorinated acceptor groups and their interactions were estimated with the nicotinic acetylcholine receptor (nAChR) binding site by molecular docking studies, to evaluate their larvicidal activity against A. darlingi, and to assess their outdoor photodegradation behavior. New neonicotinoid analogues were prepared and characterized by NMR and mass-spectrometry. The synthesized molecules were modelled by time-dependent density functional theory and analyzed, their interaction with nAChR was investigated by molecular docking. Their insecticide activity was tested on Anopheles larvae collected in suburban area of Manaus, Brazil. Four new fluorinated neonicotinoid analogs were prepared and tested against 3rd instars larvae of A. darlingi showing high larvicidal activity. Docking studies reveal binding modes of the synthesized compounds and suggest that their insecticidal potency is governed by specific interactions with the receptor binding site and enhanced lipophilicity. 2-Chloro-5-(2-trifluoromethyl-pyrrolidin-1-ylmethyl)pyridine 5 showed fast degradation in water maintaining high larvicidal activity. All obtained substances possessed high larvicidal activity in low concentrations in 48 hours of exposure, compared to commercial flupyradifurone. Such activity is connected to a unique binding pattern of the synthesized compounds to insect's nAChR and to their enhanced bioavailability owing to introduction of fluorinated amino-moieties. Therefore, the compounds in question have a high potential for application as control agents for insects transmitting tropical diseases, and they will be less persistent in the environment.
- da Silva Mesquita, Rochelly,Kyrylchuk, Andrii,Grafova, Iryna,Kliukovskyi, Denys,Bezdudnyy, Andriy,Rozhenko, Alexander,Tadei, Wanderli Pedro,Leskel?, Markku,Grafov, Andriy
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- Novel compound 1 - bromo -2 , 4, 6 -trifluoro -3, 5 -bis (trifluoromethyl) benzene and preparation method thereof (by machine translation)
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The invention relates to the field of industrial organic synthesis, and particularly discloses a compound shown as a formula I, and the chemical formula is 1 - bromo -2 , 4, 6 -trifluoro -3, 5 -trifluoromethyl benzene and a preparation method thereof. The method comprises the steps of nitration, catalytic hydrogenation, chlorination, diazotization, fluoro and the like. The preparation method has the characteristics of easily available raw materials, simple process, controllable reaction conditions and the like, is suitable for industrial production and can be used as a key intermediate to prepare OLED materials. (by machine translation)
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- Electronic Structures and Reactivity Profiles of Aryl Nitrenoid-Bridged Dicopper Complexes
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Dicopper complexes templated by dinucleating, pacman dipyrrin ligand scaffolds (Mesdmx, tBudmx: Dimethylxanthine-bridged, cofacial bis-dipyrrin) were synthesized by deprotonation/metalation with mesitylcopper (CuMes; Mes: Mesityl) or by transmetalation with cuprous precursors from the corresponding deprotonated ligand. Neutral imide complexes (Rdmx)Cu2(μ2-NAr) (R: Mes, tBu; Ar: 4-MeOC6H4, 3,5-(F3C)2C6H3) were synthesized by treatment of the corresponding dicuprous complexes with aryl azides. While one-electron reduction of (Mesdmx)Cu2(μ2-N(C6H4OMe)) with potassium graphite initiates an intramolecular, benzylic C-H amination at room temperature, chemical reduction of (tBudmx)Cu2(μ2-NAr) leads to isolable [(tBudmx)Cu2(μ2-NAr)]-product salts. The electronic structures of the thermally robust [(tBudmx)Cu2(μ2-NAr)]0/-complexes were assessed by variable-temperature electron paramagnetic resonance spectroscopy, X-ray absorption spectroscopy (Cu L2,3/K-edge, N K-edge), optical spectroscopy, and DFT/CASSCF calculations. These data indicate that the formally Class IIIA mixed valence complexes of the type [(Rdmx)Cu2(μ2-NAr)]-feature significant NAr-localized spin following reduction from electronic population of the [Cu2(μ2-NAr)] ? manifold, contrasting previous methods for engendering iminyl character through chemical oxidation. The reactivity of the isolable imido and iminyl complexes are examined for prototypical radical-promoted reactivity (e.g., nitrene transfer and H-atom abstraction), where the divergent reactivity is rationalized by the relative degree of N-radical character afforded from different aryl substituents.
- Carsch, Kurtis M.,Lukens, James T.,Dimucci, Ida M.,Iovan, Diana A.,Zheng, Shao-Liang,Lancaster, Kyle M.,Betley, Theodore A.
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supporting information
p. 2264 - 2276
(2020/02/18)
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- Copper(ii)-catalyzed c-n coupling of aryl halides and n-nucleophiles promoted by quebrachitol or diethylene glycol
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Herein, we report the natural ligand quebrachitol (QCT) as a promoter for a Cu(II) catalyst, which is highly effective for N-Arylation of various amines and related aryl halides. A series of diarylamine derivatives were obtained in high yields by using diethylene glycol (DEG) as both ligand and solvent. The C-N coupling reactions proceed under mild conditions and exhibit good functional group tolerance.
- Chen, Guoliang,Chen, Yuanguang,Du, Fangyu,Fu, Yang,Wu, Ying,Zhou, Qifan
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supporting information
p. 2161 - 2168
(2019/11/25)
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- Unclicking of thioureas: Base catalyzed elimination of anilines and isothiocyanates from thioureas
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Bisaromatic thioureas are widely used in e.g. asymmetric organocatalysis and considered to be robust compounds. Herein we show, in strong contrast to common notion, that thioureas dissociate to amines and isothiocyanates in a base catalyzed reaction under mild conditions. This ‘unclicking’ process can occur in the presence of weak organic bases even at moderate temperatures. The influence of the substituents at the aromatic rings of the thiourea on the regioselectivity of this unclicking process is also shown.
- Vlatkovi?, Matea,Feringa, Ben L.
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p. 2188 - 2192
(2019/03/05)
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- New thiourea organocatalysts and their application for the synthesis of 5-(1H-indol-3-yl)methyl-2,2-dimethyl-1,3-dioxane-4,6-diones a source of chiral 3-indoylmethyl ketenes
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The stereoselective properties of modified thiourea organocatalysts were tested in the Friedel–Crafts alkylation of indole with 5-arylidene-2,2-dimethyl-1,3-dioxane-4,6-diones, which produces chiral 5-((1H-indol-3-yl)(aryl)methyl)-2,2-dimethyl-1,3-dioxane-4,6-diones. Based on a tentative reaction mechanism for ((S)-N-benzyl-2-(3-(3,5-bis(trifluoromethyl)phenyl)thioureido)-N,3,3-trimethylbutanamide organocatalysts, modifications were applied in four selected regions. Systematic structure-stereoselectivity relationship study allowed designing the best efficient organocatalyst for the investigated Friedel–Crafts alkylation of indole with 5-arylidene-2,2-dimethyl-1,3-dioxane-4,6-diones.
- Najda-Mocarska, Ewelina,Zakaszewska, Anna,Janikowska, Karolina,Makowiec, S?awomir
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supporting information
p. 14 - 25
(2017/12/26)
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- Selective Hydrogenation of Amides to Amines and Alcohols Catalyzed by Improved Iron Pincer Complexes
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A comparative study on the synthesis, stability, and catalytic activity of various iron pincer complexes with the general formula [(R-PNHP)Fe(H) (CO) (BH4)] is reported, where R denotes the substituent of the terminal PR2-groups (R = tBu, Cy, iPr, Ph, Et). By the example of the synthesized precatalysts, it is shown that the nature of the ligands has a surprising influence on the catalytic properties of the complexes. Bulky ligands and less electron donating ligands affect the stability of the complexes, which preferably react under the loss of CO or H2 to deactivated products. In return, the reduced steric demand and the strong σ-donating properties of the Et-substituted precatalyst (2a) lead to an improved activity in the hydrogenation of esters to alcohols, compared to that of the previously reported iPr-substituted complexes. The improved activity of complex 2a is clearly demonstrated in the direct hydrogenation of amides to alcohols and amines under mild conditions.
- Schneck, Felix,Assmann, Maik,Balmer, Markus,Harms, Klaus,Langer, Robert
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p. 1931 - 1943
(2016/07/06)
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- Amination-Oxidation Strategy for the Copper-Catalyzed Synthesis of Monoarylamines
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A novel approach for the synthesis of monoarylamines from aryl halides is presented. This method employs an inexpensive, nontoxic metal source (copper) and incorporates a stable ammonia surrogate (α-amino acids), obviating the need for special experimental setup or handling of ammonia reagents. This process, which is proposed to proceed via an amination-oxidation sequence, selectively promotes the transformation of a range of aryl and heteroaryl iodides as well as bromides to the corresponding monoarylamines.
- Thomas, Christopher,Wu, Marvin,Billingsley, Kelvin L.
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p. 330 - 335
(2016/01/15)
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- Mild and highly selective palladium-catalyzed monoarylation of ammonia enabled by the use of bulky biarylphosphine ligands and palladacycle precatalysts
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A method for the Pd-catalyzed arylation of ammonia with a wide range of aryl and heteroaryl halides, including challenging five-membered heterocyclic substrates, is described. Excellent selectivity for monoarylation of ammonia to primary arylamines was achieved under mild conditions or at rt by the use of bulky biarylphosphine ligands (L6, L7, and L4) as well as their corresponding aminobiphenyl palladacycle precatalysts (3a, 3b, and 3c). As this process requires neither the use of a glovebox nor high pressures of ammonia, it should be widely applicable.
- Cheung, Chi Wai,Surry, David S.,Buchwald, Stephen L.
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supporting information
p. 3734 - 3737
(2013/08/23)
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- The [Cu]-catalyzed SNAR reactions: Direct amination of electron deficient aryl halides with sodium azide and the synthesis of arylthioethers under Cu(II) - Ascorbate redox system
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A one pot [Cu]-promoted SNAr reaction of electron-deficient halobenzenes with sodium azide and the reduction of the intermediate aryl azides under the same Cu(II)-ascorbate redox conditions leading to anilines has been documented. Control experiments revealed that both ascorbate and proline play important role in the reaction path way. Further, the use of this catalytic Cu(II)-ascorbate redox system has been explored for the synthesis of arylthioethers.
- Goriya, Yogesh,Ramana
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experimental part
p. 7642 - 7650
(2010/12/19)
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- Palladium-catalyzed coupling of ammonia with aryl chlorides, bromides, iodides, and sulfonates: A general method for the preparation of primary arylamines
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We report that the complex generated from Pd[P(o-tol)3] 2 and the alkylbisphosphine CyPF-t-Bu is a highly active and selective catalyst for the coupling of ammonia with aryl chlorides, bromides, iodides, and sulfonates. The couplings of ammonia with this catalyst conducted with a solution of ammonia in dioxane form primary arylamines from a variety of aryl electrophiles in high yields. Catalyst loadings as low as 0.1 mol % were sufficient for reactions of many aryl chlorides and bromides. In the presence of this catalyst, aryl sulfonates also coupled with ammonia for the first time in high yields. A comparison of reactions in the presence of this catalyst versus those in the presence of existing copper and palladium systems revealed a complementary, if not broader, substrate scope. The utility of this method to generate amides, imides, and carbamates is illustrated by a one-pot synthesis of a small library of these carbonyl compounds from aryl bromides and chlorides, ammonia, and acid chlorides or anhydrides. Mechanistic studies show that reactions conducted with the combination of Pd[P(o-tol)3]2 and CyPF-t-Bu as catalyst occur with faster rates and higher yields than those conducted with CyPF-t-Bu and palladiun(II) as catalyst precursors because of the low concentration of active catalyst that is generated from the combination of palladium(II), ammonia, and base.
- Vo, Giang D.,Hartwig, John F.
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supporting information; experimental part
p. 11049 - 11061
(2009/12/05)
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- Palladium-catalyzed silane/siloxane reductions in the one-pot conversion of nitro compounds into their amines, hydroxylamines, amides, sulfonamides, and carbamates
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A combination of palladium(II) acetate, aqueous potassium fluoride, and polymethylhydrosiloxane (PMHS) facilitates the room-temperature reduction of aromatic nitro compounds to anilines. These reactions tend to be quick (30 min), high-yielding, and tolerate a range of other functional groups. Replacement of PMHS/KF with triethylsilane allows for the reduction of aliphatic nitro compounds to their corresponding hydroxylamines. Depending on the substrate, both conditions can allow for the in situ conversion of the product amines into amides, sulfonamides, and carbamates. Georg Thieme Verlag Stuttgart.
- Rahaim Jr., Ronald J.,Maleczka Jr., Robert E.
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p. 3316 - 3340
(2008/09/17)
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- Catalyst compositon for olefin polymerization
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The invention relates to a catalyst composition comprising a salt of a non- or weakly coordinating anion, said non- or weakly coordinating anion comprising at least one metal or metalloid ion M with valency v+, v representing an integer between 1 and 5, and at least one bidentate ligand coordinating to this metal or metalloid ion, and a catalyst that can be activated by said non- or weakly coordinating anion, characterized in that said bidentate ligand is a bidentate monoanionic ligand of formula (I): (R1qA1-X-A2R2r), wherein X represents a bridging moiety; A1 and A2 are each independently chosen from the group comprising N, O, P, S, and C; R1 and R2 are each independently chosen from the group comprising an optionally substituted linear or branched (hetero)alkyl group, an optionally substituted (hetero)aryl group, and a Si containing group; and q and r each independently represent an integer with 0≦q, r≦2.
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- Zinc trimethylsilylamide as a mild ammonia equivalent and base for the amination of aryl halides and triflates
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(Chemical Equation Presented) We report that Zn[N(SiMe3) 2]2 is a mild ammonia equivalent and base for the palladium-catalyzed amination of aryl halides and triflates. In contrast to LiN(SiMe3)2, the combination of Zn[N(SiMe 3)2]2 and LiCl coupled with aryl halides and triflates containing base-sensitive functionality in high yields. In addition, aryl bromides coupled with aryl and alkylamines with the combination of Zn[N(SiMe3)2]2 and LiCl as base. These aminations occurred without racemization of the enolizable stereocenter of an optically active ester.
- Lee, Dae-Yon,Hartwig, John F.
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p. 1169 - 1172
(2007/10/03)
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- Allylic amination of unfunctionalyzed olefins by nitroarenes and CO, catalyzed by Ru3(CO)12/Ph-BIAN (Ph-BIAN=bis(phenylimino) acenaphthenequinone): Extension to the synthesis of allylic amines with strongly electron-withdrawing or el
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The allylic amination of unfunctionalyzed olefins by nitroarenes under CO pressure, catalyzed by Ru3(CO)12/Ph-BIAN (Ph-BIAN=bis(phenylimino)acenaphthenequinone) has been extended to some substrates with strongly electron-withdrawing
- Ragaini, Fabio,Cenini, Sergio,Turra, Fabrizio,Caselli, Alessandro
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p. 4989 - 4994
(2007/10/03)
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- Trifluoromethyl derivatives of cyclohexanol and cyclohexanone and their reactions
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The catalytic hydrogenation of mono- and bistrifluoromethylphenols was investigated, and the structure of the obtained trifluoromethylcyclohexanols was established.Methods were developed for the production of trifluoromethyl derivatives of caprolactam and adipic acid.
- Zalesskaya, I. M.,Blakitnyi, A. N.,Saenko, E. P.,Fialkov, Yu. A.,Yagupol'skii, L. M.
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p. 1031 - 1038
(2007/10/02)
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