- Novel aza-BODIPY based small molecular NIR-II fluorophores for: In vivo imaging
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The development of new NIR-II fluorophores, particularly those with facile syntheses, high fluorescence quantum yields, and stable and tunable photophysical properties, is challenging. Herein, we report a new class of small molecular NIR-II fluorophores based on aza-dipyrromethene boron difluoride (aza-BODIPY) dyes. We demonstrate promising photophysical properties of these dyes, such as large Stokes shift, superior photostability, and good fluorescence brightness as nanoparticles in aqueous solution. Because of these properties and high resolution and deep penetration NIR-II imaging ability, the aza-BODIPY based dyes show great potential as NIR-II imaging agents.
- Bai, Lei,Sun, Pengfei,Liu, Yi,Zhang, Hang,Hu, Wenbo,Zhang, Wansu,Liu, Zhipeng,Fan, Quli,Li, Lin,Huang, Wei
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Read Online
- Covalent Organic Frameworks toward Diverse Photocatalytic Aerobic Oxidations
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Photoactive two-dimensional covalent organic frameworks (2D-COFs) have become promising heterogenous photocatalysts in visible-light-driven organic transformations. Herein, a visible-light-driven selective aerobic oxidation of various small organic molecules by using 2D-COFs as the photocatalyst was developed. In this protocol, due to the remarkable photocatalytic capability of hydrazone-based 2D-COF-1 on molecular oxygen activation, a wide range of amides, quinolones, heterocyclic compounds, and sulfoxides were obtained with high efficiency and excellent functional group tolerance under very mild reaction conditions. Furthermore, benefiting from the inherent advantage of heterogenous photocatalysis, prominent sustainability and easy photocatalyst recyclability, a drug molecule (modafinil) and an oxidized mustard gas simulant (2-chloroethyl ethyl sulfoxide) were selectively and easily obtained in scale-up reactions. Mechanistic investigations were conducted using radical quenching experiments and in situ ESR spectroscopy, all corroborating the proposed role of 2D-COF-1 in photocatalytic cycle.
- Liu, Shuyang,Tian, Miao,Bu, Xiubin,Tian, Hua,Yang, Xiaobo
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supporting information
p. 7738 - 7744
(2021/05/07)
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- Sodium Triethylborohydride-Catalyzed Controlled Reduction of Unactivated Amides to Secondary or Tertiary Amines
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The first transition-metal-free catalytic protocol for controlled reduction of amide functions using cheap and bench-stable hydrosilanes as reducing agents has been established. By altering the hydrosilane and solvent, the new method enables the selective cleavage of unactivated C-O bonds in amides and allows the C-N bonds to selectively break via the deacylated cleavage. Overall, this novel process may offer a versatile alternative to current methodologies employing stoichiometric metal systems for the controlled reduction of carboxamides.
- Yao, Wubing,He, Lili,Han, Deman,Zhong, Aiguo
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- Sodium Triethylborohydride-Catalyzed Controlled Reduction of Unactivated Amides to Secondary or Tertiary Amines
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The first transition-metal-free catalytic protocol for controlled reduction of amide functions using cheap and bench-stable hydrosilanes as reducing agents has been established. By altering the hydrosilane and solvent, the new method enables the selective cleavage of unactivated C-O bonds in amides and allows the C-N bonds to selectively break via the deacylated cleavage. Overall, this novel process may offer a versatile alternative to current methodologies employing stoichiometric metal systems for the controlled reduction of carboxamides.
- Yao, Wubing,He, Lili,Han, Deman,Zhong, Aiguo
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p. 14627 - 14635
(2019/12/02)
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- B(C6F5)3-Catalyzed Deoxygenative Reduction of Amides to Amines with Ammonia Borane
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The first B(C6F5)3-catalyzed deoxygenative reduction of amides into the corresponding amines with readily accessible and stable ammonia borane (AB) as a reducing agent under mild reaction conditions is reported. This metal-free protocol provides facile access to a wide range of structurally diverse amine products in good to excellent yields, and various functional groups including those that are reduction-sensitive were well tolerated. This new method is also applicable to chiral amide substrates without erosion of the enantiomeric purity. The role of BF3 ? OEt2 co-catalyst in this reaction is to activate the amide carbonyl group via the in situ formation of an amide-boron adduct. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Han, Jiahong,Xu, Xin,Chen, Changjun,Zhao, Haoqiang,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 2301 - 2308
(2019/01/30)
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- Ru-Catalyzed Deoxygenative Transfer Hydrogenation of Amides to Amines with Formic Acid/Triethylamine
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A ruthenium(II)-catalyzed deoxygenative transfer hydrogenation of amides to amines using HCO2H/NEt3 as the reducing agent is reported for the first time. The catalyst system consisting of [Ru(2-methylallyl)2(COD)], 1,1,1-tris(diphenylphosphinomethyl) ethane (triphos) and Bis(trifluoromethane sulfonimide) (HNTf2) performed well for deoxygenative reduction of various secondary and tertiary amides into the corresponding amines in high yields with excellent selectivities, and exhibits high tolerance toward functional groups including those that are reduction-sensitive. The choice of hydrogen source and acid co-catalyst is critical for catalysis. Mechanistic studies suggest that the reductive amination of the in situ generated alcohol and amine via borrowing hydrogen is the dominant pathway. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Xu, Xin,Zhao, Haoqiang,Han, Jiahong,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 3800 - 3806
(2019/07/12)
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- Method for selective reducing reaction of tertiary aryl amide and borane
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The present invention relates to a method for a selective reducing reaction of a tertiary aryl amide and borane. A tertiary amine product is prepared by the reducing reaction of a tertiary aryl amidederivative and a cheap and easily available organoboron reagent under mild conditions under the convenient catalysis of a non-transition metal compound sodium triethylborohydride used as a catalyst for the first time. Compared with traditional methods, the method of the method generally has the advantages of wide universality of a substrate, low cost and easy availability of the catalyst, and simplicity in reaction operation. The selective reducing reaction of the tertiary aryl amide compound and the organoboron reagent under the catalysis of the transition metal catalyst is realized for the first time, and a brand new "green" reaction strategy is provided for the laboratory preparation or industrial production of tertiary arylamine products.
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Paragraph 0085-0088
(2019/10/23)
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- Iridium-Catalyzed Direct Cyclization of Aromatic Amines with Diols
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We developed an environmentally friendly iridium-catalyzed direct cyclization of aromatic amines with diols that generates the corresponding N-heterocyclic compounds with water as the sole by-product. Thus, under conditions of 165 °C for 18 hours, the direct cyclization of N -methylanilines with 1,3-propanediol by using an IrCl 3 catalyst with rac -BINAP as a ligand in mesitylene afforded the corresponding tetrahydroquinoline derivatives with yields ranging from 73 to 83%. Under similar reaction conditions, direct cyclization of anilines with 1,3-propanediol produced the corresponding tetrahydrobenzoquinolizine derivatives with yields ranging from 26 to 76%.
- Minakawa, Maki,Watanabe, Kouichi,Toyoda, Satoru,Uozumi, Yasuhiro
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p. 2385 - 2389
(2018/11/23)
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- Method for efficiently preparing tetrahydroquinoline compound, and catalyst with acid or alkaline carrier supporting Ni metal
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The invention relates to a method for efficiently preparing a tetrahydroquinoline compound, and a catalyst with an acid or alkaline carrier supporting Ni metal, and belongs to the field of biomass ethanol conversion. The invention also relates to an application of the co-catalyst with a metal active center and the solid acid or alkaline carrier in the synthesis of 1,2,3,4-tetrahydroquinoline, andbelongs to the technical field of biomass ethanol conversion. The catalyst consists of uniformly dispersed nickel nano particles and a nickel-aluminum (zirconium) composite oxide. The catalyst is prepared by in-situ topological transformation of nickel-containing hydrotalcite (NiAl-LDHs, NiAlZr-LDHs), and has the advantages that a strong interface interaction exists between the Ni nano particles and the carrier. When a reaction is carried out at the temperature of 125 DEG for 16 hours, and the yield of 1,2,3,4-tetrahydroquinoline by the catalysis of Ni-NiAl-LDO can reach 97%. When the reactionis carried out for 26 hours, the yield of 1,2,3,4-tetrahydroquinoline by the catalysis of Ni-NiAlZr-LDO can reach 95%.
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Paragraph 0023; 0025; 0026
(2018/11/27)
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- Novel nonmetal catalytic bidirectional selective reduction method of tertiary aromatic amide
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The invention relates to a novel effective bidirectional selective environment-friendly method for hydrosilation reduction of tertiary aromatic amide and an organic silicon reagent. The method comprises the following steps: selecting a nonmetal catalytic system, and selectively preparing a secondary or tertiary organic amine compound by successively catalyzing tertiary aromatic amide and cheap PHMS or triethoxysilane under a mild condition. By adopting the method, the bidirectional selective reduction of the tertiary aromatic amide is realized by innovatively utilizing an electronic effect and steric hindrance difference of an organic silicon reagent at first time, so that a brand new strategy is provided for the reduction of amide and derivative of the amide, the defects of the traditional method that the substrate functional group is poor in compatibility, the production cost is high and the like can be overcome, and the application prospect of the amine compound prepared in industrial production or laboratory is promising.
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Paragraph 0094; 0095; 0096; 0097
(2017/10/22)
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- Rhenium-Loaded TiO2: A Highly Versatile and Chemoselective Catalyst for the Hydrogenation of Carboxylic Acid Derivatives and the N-Methylation of Amines Using H2 and CO2
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Herein, we report a heterogeneous TiO2-supported Re catalyst (Re/TiO2) that promotes various selective hydrogenation reactions, which includes the hydrogenation of esters to alcohols, the hydrogenation of amides to amines, and the N-methylation of amines, by using H2 and CO2. Initially, Re/TiO2 was evaluated in the context of the selective hydrogenation of 3-phenylpropionic acid methyl ester to afford 3-phenylpropanol (pH2 =5 MPa, =5 MPa, T=180 °C), which revealed a superior performance over other catalysts that we tested in this study. In contrast to other typical heterogeneous catalysts, hydrogenation reactions with Re/TiO2 did not produce dearomatized byproducts. DFT studies suggested that the high selectivity for the formation of alcohols in favor of the hydrogenation of aromatic rings is ascribed to the higher affinity of Re towards the COOCH3 group than to the benzene ring. Moreover, Re/TiO2 showed a wide substrate scope for the hydrogenation reaction (19 examples). Subsequently, this Re/TiO2 catalyst was applied to the hydrogenation of amides, the N-methylation of amines, and the N-alkylation of amines with carboxylic acids or esters.
- Toyao, Takashi,Siddiki,Morita, Yoshitsugu,Kamachi, Takashi,Touchy, Abeda S.,Onodera, Wataru,Kon, Kenichi,Furukawa, Shinya,Ariga, Hiroko,Asakura, Kiyotaka,Yoshizawa, Kazunari,Shimizu, Ken-Ichi
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supporting information
p. 14848 - 14859
(2017/10/27)
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- Towards a general ruthenium-catalyzed hydrogenation of secondary and tertiary amides to amines
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A broad range of secondary and tertiary amides has been hydrogenated to the corresponding amines under mild conditions using an in situ catalyst generated by combining [Ru(acac)3], 1,1,1-tris(diphenylphosphinomethyl)ethane (Triphos) and Yb(OTf)3. The presence of the metal triflate allows to mitigate reaction conditions compared to previous reports thus improving yields and selectivities in the desired amines. The excellent isolated yields of two scale-up experiments corroborate the feasibility of the reaction protocol. Control experiments indicate that, after the initial reduction of the amide carbonyl group, the reaction proceeds through the reductive amination of the alcohol with the amine arising from collapse of the intermediate hemiaminal.
- Cabrero-Antonino, Jose R.,Alberico, Elisabetta,Junge, Kathrin,Junge, Henrik,Beller, Matthias
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p. 3432 - 3442
(2016/05/19)
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- Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines
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The synthesis of novel tetrahydroquinolines (THQ) and dihydroquinolines (DHQ) are reported using three practical, scalable synthetic approaches to access highly lipophilic analogues bearing a 6-iodo substituent, each with a different means of cyclisation. A versatile and stable quinolin-2-one intermediate was identified, which could be reduced to the corresponding THQ with borane reagents, or to the DHQ with diisobutylaluminium hydride via a novel elimination that is more favourable at higher temperatures. Coupling these strongly electron-donating scaffolds to electron-accepting moieties caused the resulting structures to exhibit strong fluorescence.
- Chisholm, David R.,Zhou, Garr-Layy,Pohl, Ehmke,Valentine, Roy,Whiting, Andrew
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p. 1851 - 1862
(2016/10/05)
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- α-Alkylation of tertiary amines by C(sp3)–C(sp3) cross-coupling under redox neutral photocatalysis
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Direct α-alkylation of N-phenyl-tetrahydroisoquinoline with alkyl selenides of desired alkyl chain length and functionality is reported by photoredox catalysis. Construction of hexahydro pyrrolo- and pyrido-isoquinoline scaffolds along with indolines and tetrahydroquinolines is also described by intramolecular C(sp3)–C(sp3) cross-couplings.
- Pandey, Ganesh,Tiwari, Sandip Kumar,Singh, Bhawana
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supporting information
p. 4480 - 4483
(2016/09/14)
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- Cu(ii)-catalyzed C-H (SP3) oxidation and C-N cleavage: Base-switched methylenation and formylation using tetramethylethylenediamine as a carbon source
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Base-switched methylenation and formylation using tetramethylethylenediamine (TMEDA) as a carbon source have been achieved under mild conditions, catalyzed by CuCl2, with atmospheric oxygen as oxidant. Bisindolylmethanes, diphenylmethanes and 3-formylindoles were synthesized with excellent regioselectivity and good yield.
- Zhang, Lei,Peng, Chen,Zhao, Dan,Wang, Yue,Fu, Hai-Jian,Shen, Qi,Li, Jian-Xin
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supporting information; experimental part
p. 5928 - 5930
(2012/07/27)
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- An efficient one pot transfer hydrogenation and N-alkylation of quinolines with alcohols mediated by Pd/C/Zn
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A Pd/C/Zn mixture with alcohols has been revealed to be an efficient transfer hydrogenation system to quinolines. Furthermore, the metals mixture is able to activate alcohols as N-alkylating agents in a hydrogen autotransfer process. 1,2,3,4-Tetrahydroquinolines and N-alkylated tetrahydroquinolines from quinolines have been obtained with excellent yields in one step.
- Abarca, Belen,Adam, Rosa,Ballesteros, Rafael
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experimental part
p. 1826 - 1833
(2012/04/23)
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- A facile one-pot synthesis of N-substituted tetrahydroquinolines
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An uncatalyzed one-pot synthesis of N-substituted tetrahydroquinolines was achieved in good yields by the reaction of quinoline and alkyl/acyl halides with Hantzsch dihydropyridine ester under mild reaction conditions.
- Babu, Thelagathoti Hari,Shanthi, Gnanamani,Perumal, Paramasivan T.
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experimental part
p. 2881 - 2884
(2009/09/06)
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- Regio- and chemoselective transfer hydrogenation of quinolines catalyzed by a Cp*Ir complex
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An efficient method for the transfer hydrogenation of quinolines catalyzed by a Cp*Ir complex was developed. A variety of 1,2,3,4-tetrahydroquinolines were obtained by regio- and chemoselective transfer hydrogenation of quinolines using 2-propanol as a hydrogen source.
- Fujita, Ken-Ichi,Kitatsuji, Chihiro,Furukawa, Shigetoyo,Yamaguchi, Ryohei
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p. 3215 - 3217
(2007/10/03)
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- Efficient nickel-mediated intramolecular amination of aryl chlorides
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(Matrix presented) The use of an in situ generated Ni(0) catalyst associated with 2,2′-bipyridine or N,N′ -bis(2,6-diisopropylphenyl)dihydroimidazol-2-ylidene (SIPr) as a ligand and NaO-t-Bu as the base for the intramolecular coupling of aryl chlorides with amines is described. The procedure has been applied to the formation of five-, six-, and seven-membered rings.
- Omar-Amrani, Rafik,Thomas, Antoine,Brenner, Eric,Schneider, Raphael,Fort, Yves
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p. 2311 - 2314
(2007/10/03)
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- Hypoglycemic thiazolidinediones
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Hypoglycemic 5-[1-(5,6,7,8-tetrahydro-2-napthyl-; 1,2,3,4-tetrahydro-6-quinolyl-; 2-indanyl-; and 2-indolyl)alkyl]thiazolidine-2,4-dione derivatives, pharmaceutically acceptable salts thereof, and a method for their use in the treatment of hyperglycemic mammals.
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- A Convenient Preparation of N-Acyl-1,2-dihydroquinoline
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N-Acetyl- and N-formyl-1,2-dihydroquinolone were conviniently prepared by reductive acylation of quinoline without isolating the labile 1,2-dihydroquinoline.This method was also applied to isoquinoline to prepare N-acetyl-1,2-dihydroisoquinoline.
- Katayama, Hajime,Ohkoshi, Mitsuko,Yasue, Masaiti
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p. 2226 - 2228
(2007/10/02)
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