- Direct C-3 alkylation of coumarins via decarboxylative coupling with carboxylic acids
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A new method for selective C-3 alkylation of coumarins using carboxylic acids as alkyl sources is reported. This process offers a practical method for the facile construction of 3-alkyl coumarins with a broad substrate scope. The reaction works under metal-free and aqueous media and both cyclic and acyclic aliphatic carboxylic acids participate in this radical C-C cross coupling reaction.
- Jafarpour, Farnaz,Darvishmolla, Masoumeh,Azaddoost, Narges,Mohaghegh, Farid
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- Chlorophyll-catalyzed photochemical regioselective coumarin C-H arylation with diazonium salts
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This communication describes the development of a mild method for the cross-coupling of the C3-position of coumarin with an array of diazonium salts mediated by chlorophyll as a biocatalyst via visible light catalysis. A natural pigment such as chlorophyll is used as a green photosensitizer and environmentally benign catalyst. This general and easy procedure provides a transition-metal-free alternative for the formation of 3-aryl coumarin derivatives at room temperature with good to excellent yields. This journal is
- Moazzam, Ali,Jafarpour, Farnaz
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supporting information
p. 16692 - 16696
(2020/10/27)
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- Facile one-pot synthetic access to libraries of diversely substituted 3-aryl (Alkyl)-coumarins using ionic liquid (IL) or conventional base/solvent, and an IL-mediated approach to novel coumarin-bearing diaryl-ethynes
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The in-situ formed carbonylimidazole derivatives of Ar(alkyl)-CH2COOH react at r.t. with substituted salicylaldehydes in [BMIM][PF6] or [BMIM][BF4] as solvent, and [PAIM][NTf2] as basic-IL, to produce libraries of 3-aryl(alkyl)coumarins. Whereas these reactions can also be performed with similar efficiency in THF by employing DBU, the IL approach offers easier work-up and recycling of the IL solvent. An IL-mediated approach to the synthesis of novel coumarin-bearing diaryl-ethynes by the Sonogshira reaction is also reported, and the potential for recycling/reuse of the IL solvent is shown.
- Kalkhambkar, Rajesh G.,Laali, Kenneth K.,Malunavar, Shruti S.,Prabhala, Pavankumar,Savanur, Hemantkumar M.,Sutar, Suraj M.
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supporting information
(2020/04/08)
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- Visible-light-driven copper-catalyzed aerobic oxidative cascade cyclization of N-tosylhydrazones and terminal alkynes: Regioselective synthesis of 3-arylcoumarins
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We present the first example of sustainable, intuitive, highly regioselective, visible-light-driven copper catalyzed aerobic oxidative cascade cyclization of N-tosylhydrazones with terminal alkynes for the preparation of 3-arylcoumarins at room temperature. This operationally simple methodology has been successfully applied to a wide range of N-tosylhydrazones and alkynes (49 examples), and proceeds well to afford biologically active compounds, such as monoamine oxidase B (MAO-B) inhibitor and horseradish peroxidase (HRP) inhibitor, in satisfactory yields under mild conditions. Furthermore, mechanistic studies suggest that the reaction proceeds via a copper(ii)-superoxo or -peroxo complex mediated oxidative annulation of terminal alkynes, as evidenced by 18O2 isotopic-labelling experiments.
- Ragupathi, Ayyakkannu,Sagadevan, Arunachalam,Charpe, Vaibhav Pramod,Lin, Chun-Cheng,Hwu, Jih-Ru,Hwang, Kuo Chu
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supporting information
p. 5151 - 5154
(2019/05/10)
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- Zn(II)-Catalyzed One-Pot Synthesis of Coumarins from Ynamides and Salicylaldehydes
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A highly efficient and straightforward synthesis of diversely substituted coumarins from ynamides and salicylaldehydes in the presence of Zn(II) catalyst has been developed. The sulfonamide moiety of ynamides was successfully recycled in this process, serving as an effective traceless directing group for high regioselectivity in the bond-forming event. The advantages of this protocol are good functional group tolerance, broad substrate scope, simple and high-yielding reaction, recovery/reuse of the sulfonamides, low catalyst loading of inexpensive catalyst, and, by these merits, a more cost-effective and greener process.
- Yoo, Huen Ji,Youn, So Won
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supporting information
p. 3422 - 3426
(2019/05/10)
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- Rational design of slightly twisted coumarin molecules with remarkable solution and solid dual efficient luminescence
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Endowing slightly twisted molecules highly emissive in both solution and solid state is of great importance for understanding the principle of maximizing the luminescent efficiency of luminophores. To this end, a series of slightly twisted coumarin luminophores CMs with different alkoxyl substituents at the 7-positions were synthesized. The effect of the substitutes on the diversity photophysical properties of the four compounds in solution, THF/H2O mixtures and solid state were investigated. Comparing to the referenced compound CM (3-p-tolyl-2H-chromen-2-one) that without a substitute, the introduced electron-rich alkoxyl substitutes not only enhanced the intramolecular charge transfer (ICT) effect, but also significantly modified their molecular packing patterns in the crystals. The combined effect of increasing the radiative and suppressing the nonradiactive pathways boosted the luminescence efficiency of CM1-CM3 in solution and the solid state simultaneously. Eventually, compound CM2 with an ethoxyl substitute exhibited the strongest blue emission with fluorescence quantum yields as high as 73.2% and 96.7% in solution and the solid state, respectively. This work presents an efficient strategy towards dual strong fluorescent luminophores in both solution and the solid state.
- Sun, Yue,Wu, Tong,Zhang, Fang,Zhang, Rong,Wu, Min,Wu, Yuezhen,Liang, Xiaozhong,Guo, Kunpeng,Li, Jie
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- Pd-catalysed carbonylative annulation of salicylaldehydes with benzyl chlorides using N-formylsaccharin as a CO surrogate
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A convenient and highly efficient Pd-catalysed carbonylative annulation of salicylaldehydes with benzyl chlorides to afford the corresponding 3-arylcoumarins in good to excellent yields has been developed. Importantly, the protocol utilizes a commercially available, low cost, solid and easy to handle N-formylsaccharin as an alternative to the highly toxic CO gas.
- Yadav, Vinod K.,Srivastava, Vishnu P.,Yadav, Lal Dhar S.
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supporting information
p. 16281 - 16286
(2018/10/04)
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- A transition-metal-free fast track to flavones and 3-arylcoumarins
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A highly regioselective and transition-metal free one-pot arylation of chromenones with arylboronic acids has been achieved employing K2S2O8. The procedure consists of a sequence of some reactions including an arylation/decarboxylation cascade and proceeds well in aqueous media to afford biologically interesting flavones and 3-arylcoumarins. This method exhibited excellent selectivity and functional group tolerance under mild conditions. The reaction also showed perfect efficacy for the preparation of styryl coumarins.
- Golshani, Mostafa,Khoobi, Mehdi,Jalalimanesh, Nafiseh,Jafarpour, Farnaz,Ariafard, Alireza
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supporting information
p. 10676 - 10679
(2017/10/06)
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- KMnO4/AcOH-mediated C3-selective direct arylation of coumarins with arylboronic acids
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An efficient protocol for KMnO4/AcOH-mediated dehydrogenative direct radical arylation of coumarins with arylboronic acids to afford 3-arylcoumarin derivatives is described. A similar reaction system is also applicable to the 3-arylation of quinolinone derivatives. These KMnO4/AcOH-mediated coupling reactions occur regioselectively at the C3 position of coumarins and quinolinones. Some notable features of this method are high efficiency, moderate to good yield, and a broad group tolerance.
- Yuan, Jin-Wei,Yang, Liang-Ru,Yin, Qiu-Yue,Mao, Pu,Qu, Ling-Bo
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p. 35936 - 35944
(2016/05/19)
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- Regioselective α-arylation of coumarins and 2-pyridones with phenylhydrazines under transition-metal-free conditions
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A facile regioselective metal-free direct α-arylation of coumarins and 2-pyridones is achieved by the reaction of coumarins and 2-pyridones with phenylhydrazine in good yields. The reaction proceeds at room temperature under mild conditions using inexpensive reagents and without the need for step intensive activating groups. The methodology is operationally simple, practically viable and also allows the coupling of similar nitrogen heterocycle aza-coumarins without prerequisite N-protection.
- Chauhan, Parul,Ravi, Makthala,Singh, Shikha,Prajapati, Prashant,Yadav, Prem P.
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p. 109 - 118
(2016/01/09)
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- Palladium-Catalyzed Zinc-Amide-Mediated C-H Arylation of Fluoroarenes and Heteroarenes with Aryl Sulfides
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C-H arylation of polyfluoroarenes and heteroarenes with aryl sulfides proceeds smoothly with the aid of a palladium-N-heterocyclic carbene catalyst. A bulky zinc amide, TMPZnCl an effective base to generate the corresponding arylzinc species in situ. This arylation protocol is practically much easier to perform than our previous method, which necessitates preparation of the arylzinc reagents in advance from the corresponding aryl halides. Aryl sulfides that are prepared through sulfur-specific reactions, such as SNAr sulfanylation and extended Pummerer reactions, undergo this direct arylation, offering interesting transformations that are otherwise difficult to achieve with conventional halogen-based organic synthesis.
- Otsuka, Shinya,Yorimitsu, Hideki,Osuka, Atsuhiro
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supporting information
p. 14703 - 14707
(2015/10/20)
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- Base-promoted synthesis of coumarins from salicylaldehydes and aryl-substituted 1,1-dibromo-1-alkenes under transition-metal-free conditions
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Facile synthesis of coumarin via the tandem reaction of salicylaldehyde with aryl-substituted 1,1-dibromo-1-alkene was developed. This new protocol proceeds smoothly under mild and transition-metal-free conditions, it allows rapid access to coumarins containing various heteroatoms that are more difficult to prepare by traditional methods. Based on the isolated intermediate of 4-(diethylamino)-3-phenylchroman-2-one and detailed mechanistic studies, a credible tandem pathway was proposed.
- Liu, Jianming,Zhang, Xin,Shi, Lijun,Liu, Muwen,Yue, Yuanyuan,Li, Fuwei,Zhuo, Kelei
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supporting information
p. 9887 - 9890
(2014/08/18)
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- A complete switch of the directional selectivity in the annulation of 2-hydroxybenzaldehydes with alkynes
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Controlling reaction selectivity is an eternal pursuit for chemists working in chemical synthesis. As part of this endeavor, our group has been exploring the possibility of constructing different natural product skeletons from the same simple starting mat
- Zeng, Huiying,Li, Chao-Jun
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supporting information
p. 13862 - 13865
(2015/01/09)
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- Synthesis of 3-arylcoumarins through N-heterocyclic carbene catalyzed condensation and annulation of 2-chloro-2-arylacetaldehydes with salicylaldehydes
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The condensation reaction of 2-chloro-2-arylacetaldehyde with salicylaldehyde catalyzed by N-heterocyclic carbene (NHC) leading to 3-arylcoumarin was studied. A number of 3-arylcoumarin derivatives were obtained in good to excellent yields via this umpolung reaction. This reaction is facile and experimentally simple and mild.
- Jiang, Yuansong,Chen, Wanzhi,Lu, Weimin
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p. 3669 - 3676
(2013/05/08)
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- Highly regioselective α-arylation of coumarins via palladium-catalyzed C-H activation/desulfitative coupling
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A novel regioselective α-arylation of coumarins with readily available arenesulfonyl chlorides and sodium arenesulfinates via palladium-catalyzed direct C-H functionalizations under mild reaction conditions is described. This protocol presents an unexpected and highly regio-controlled arylation of coumarins at C-3 to construct interesting 3-arylcoumarins with fascinating biological and fluorescent properties. The regioselectivity observed is in sharp contrast with that expected for the Heck reactions. Copyright
- Jafarpour, Farnaz,Olia, Mina Barzegar Amiri,Hazrati, Hamideh
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supporting information
p. 3407 - 3412
(2013/12/04)
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- A general palladium-catalyzed carbonylative synthesis of chromenones from salicylic aldehydes and benzyl chlorides
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Cute CO! An interesting and straightforward procedure for the carbonylative synthesis of chromenones from readily available salicylic aldehydes and benzyl chlorides has been developed (see scheme; DPPP=1,3-bis(diphenylphosphino) propane). In the presence of a palladium catalyst, various coumarins were produced in good to excellent yields. Copyright
- Wu, Xiao-Feng,Wu, Lipeng,Jackstell, Ralf,Neumann, Helfried,Beller, Matthias
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p. 12245 - 12248
(2013/09/23)
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- Palladium catalyzed dehydrogenative arylation of coumarins: An unexpected switch in regioselectivity
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A new regioselective α-arylation of coumarins with unactivated simple arenes via a palladium-catalyzed twofold C-H functionalization is devised. This method offers an attractive new approach to synthesis of a wide variety of 3-arylcoumarins from readily accessible starting materials. This journal is The Royal Society of Chemistry 2013.
- Jafarpour, Farnaz,Hazrati, Hamideh,Mohasselyazdi, Nazanin,Khoobi, Mehdi,Shafiee, Abbas
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supporting information
p. 10935 - 10937
(2013/11/19)
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- Synthesis of 3-arylcoumarins via Suzuki-cross-coupling reactions of 3-chlorocoumarin
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A convenient and innovative protocol for an efficient synthesis of different substituted 3-arylcoumarins is reported. The developed synthetic route involves a Pd-catalyzed cross-coupling reaction using a catalytic complex Pd-salen. Under these conditions a series of different substituted boronic acids have been successfully coupled to a coumarin halide to afford novel coumarins in good yields.
- Matos, Maria Joao,Vazquez-Rodriguez, Saleta,Borges, Fernanda,Santana, Lourdes,Uriarte, Eugenio
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experimental part
p. 1225 - 1227
(2011/03/22)
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- Through-bond energy transfer cassettes based on coumarin-Bodipy/distyryl Bodipy dyads with efficient energy efficiences and large pseudo-Stokes' shifts
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The energy transfer cassettes composed of coumarin and Bodipy as well as NIR distyryl Bodipys were designed to capture photonic energy and convert it to longer wavelength fluorescence emission; large pseudo-Stokes' shifts (up to 410 nm) and efficient ener
- Zhao, Yun,Zhang, Yan,Lv, Xin,Liu, Yunlong,Chen, Maliang,Wang, Pi,Liu, Jing,Guo, Wei
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supporting information; experimental part
p. 13168 - 13171
(2011/12/15)
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- Through-bond energy transfer cassettes with minimal spectral overlap between the donor emission and acceptor absorption: Coumarin-rhodamine dyads with large pseudo-stokes shifts and emission shifts
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Chemical Equation Presented Cassette recording: A new class of coumarin-rhodamine through-bond energy-transfer (TBET) cassettes with minimal spectral overlap between the donor emission and the acceptor absorption (see picture) show large pseudo-Stokes shifts (up to 230 nm) and emission shifts (up to 170 nm). The utility of this TBET platform for TBET-based probe development was demonstrated by a new ratiometric fluorescence pH probe.
- Lin, Weiying,Yuan, Lin,Cao, Zengmei,Feng, Yanming,Song, Jizeng
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supporting information; experimental part
p. 375 - 379
(2010/04/06)
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- Single-compound libraries of organic materials: Parallel synthesis and screening of fluorescent dyes
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"Hits" with high quantum yields: The screening of the chromophores of a coumarin library for optical properties allowed the identification of "hits" with high fluorescence quantum yields (see picture) which could be used as fluorescence labels and laser dyes. The generation of the library was facilitated by an efficient method involving the parallel synthesis utilizing Pd-catalyzed cross-coupling reactions.
- Schiedel, Marc-Steffen,Briehn, Christoph A.,Baeuerle, Peter
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p. 4677 - 4680
(2007/10/03)
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- A convenient synthesis of 3-arylcoumarins from arylacetonitriles
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The condensation of salicylaldehydes with various arylacetonitriles catalyzed by anion-exchange resins such as Amberlite IRA 900, leads to the corresponding 3-arylcoumarins in good yields and selectivity.
- Mhiri,Ladhar,El Gharbi,Le Bigot
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p. 1451 - 1461
(2007/10/03)
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- A CONVENIENT SYNTHESIS OF 3-ARYL COUMARINS
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A new, convenient, one-step synthesis od 3-aryl coumarins from 2-fluorobenzaldehyde and aryl acetic acids is reported.
- Ming, Yang,Boykin, David W.
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p. 3229 - 3231
(2007/10/02)
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- Synthesis of 3-Arylcoumarins, Thiacoumarins and Carbostyrils
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3-Arylcarbostyrils (2a-f), coumarins (2g-j) and thiacoumarin (2k) have been prepared by a generalised method from α,β-dibromohydrocinnamoyl derivatives (1a-k).The intermediate dihydrocoumarins and dihydrocarbostyrils (3, Y = O, NH) have been prepared which on acid treatment furnish 2.However, treatment of 3 with a base affords the 4-arylcoumarins and carbostyrils (4).
- Natarajan, M.,Manimaran, T.,Ramakrishnan, V. T.
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p. 529 - 534
(2007/10/02)
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