- An expedient solvent-free C-benzylation of 4-hydroxycoumarin with styrenes
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An efficient straightforward solvent-free C(3)-benzylation of 4-hydroxycoumarin with styrenes is performed by heating the reactants in the presence of p-toluenesulfonic acid. By this procedure, benzylated 4-hydroxycoumarin derivatives which exhibit variou
- Chatterjee, Rana,Mukherjee, Anindita,Santra, Sougata,Zyryanov, Grigory V.,Chupakhin, Oleg N.,Majee, Adinath
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p. 123 - 124
(2021/02/16)
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- HFIP Promoted C3 Alkylation of Lawsone and 4-Hydroxycoumarin with Alcohols by Dehydrative Cross-Coupling
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An environmentally benign system for the direct alkylation of lawsones and 4-hydroxycoumarins with alcohols in 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) is reported. The reaction proceeded smoothly via a dehydrative cross-coupling process by utilizing the unique properties of HFIP. A variety of alkylated products and subsequent one-pot cyclized products (pyranonaphthoquinones and pyranocoumarins) could be obtained in 40-93% yields.
- Chen, Yixin,Wang, Yurong,Zhong, Rong,Li, Jinshan
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p. 10638 - 10647
(2020/09/23)
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- Metal-Free C-O Bond Functionalization: Catalytic Intramolecular and Intermolecular Benzylation of Arenes
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A catalytic, metal-free intramolecular rearrangement of benzyl phenyl ethers using nitrosonium salt as a catalyst is described. The optimized reaction conditions enabled a catalytic and metal-free Friedel-Crafts alkylation reaction with benzylic alcohols, producing water as the stoichiometric byproduct. A comprehensive scope (>50 examples) for both approaches and application in drug synthesis were demonstrated. Mechanistic studies suggest a Lewis acid-based mechanism for the metal-free Friedel-Crafts reaction.
- Bering, Luis,Jeyakumar, Kirujan,Antonchick, Andrey P.
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supporting information
p. 3911 - 3914
(2018/07/22)
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- Regioselective Access to Structurally Diverse Coumarin Analogues through Iron-Catalysed Annulation Reactions
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A highly efficient iron-catalysed propargylation/alkyne oxacyclization/isomerization strategy is described. Biologically active furo[3,2-c]coumarins and pyrano[3,2-c]coumarins are expeditiously assembled in moderate to good yields and with a broad substrate scope. The regioselective access to different coumarins is mainly dependent on the terminal group of the secondary propargylic alcohol.
- Ren, Qiao,Kang, Jie,Li, Muyao,Yuan, Lujiang,Chen, Ruoyun,Wang, Lei
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supporting information
p. 5566 - 5571
(2017/10/13)
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- Synthesis method of propafenone drug intermediate 3-(alpha-ethylbenzyl)-4-hydroxyl coumarin
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A synthesis method of a propafenone drug intermediate 3-(alpha-ethylbenzyl)-4-hydroxyl coumarin includes the following steps that 0.21 mol of 4-hydroxyl coumarin and 0.26-0.29 mol of alpha-ethyl benzyl amine are added into a reaction vessel, the solution temperature is raised to 110-115 DEG C, the reaction time is 3-5 hours, the solution temperature is reduced to 10-15 DEG C, 300 ml of a potassium sulfite solution is added, acetonitrile is used for extracting the excessive alpha-ethyl benzyl amine, the solution is poured into 1.3 L of an oxalic acid solution, solid precipitation, filtration and washing with a saline solution are performed, a filter cake is added into 2.3 L of a potassium bromide solution, the solution temperature is raised to 90-95 DEG C and is kept for 2-3 hours, the solution temperature is reduced to 5-9 DEG C, solid precipitation, washing with cyclohexane and dehydration with a dehydrating agent are performed, and recrystallization is performed in nitromethane to obtain the crystal 3-(alpha-ethylbenzyl)-4-hydroxyl coumarin.
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Paragraph 0014; 0015; 0006
(2016/11/21)
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- Nitrimines as reagents for metal-free formal C(sp2)-C(sp2) cross-coupling reactions
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Nitrimines are employed as powerful reagents for metal-free formal C(sp2)-C(sp2) cross-coupling reactions. The new chemical process is tolerant of a wide array of nitrimine and heterocyclic coupling partners giving rise to the corresponding di- or trisubstituted alkenes, typically in high yield and with high stereoselectivity. This method is ideal for the metal-free construction of heterocycle-containing drug targets, such as phenprocoumon.
- Angeles-Dunham, Veronica V.,Nickerson, David M.,Ray, Devin M.,Mattson, Anita E.
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p. 14538 - 14541
(2015/01/16)
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- Direct catalytic benzylation of hydroxycoumarin - Efficient synthesis of warfarin derivatives and analogues
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Effective metal-catalyzed benzylations of 4-hydroxycoumarin have been developed. Employing a low amount of a cheap, nontoxic, and air-stable catalyst the 3-alkylated hydroxycoumarins were isolated in high yields after short reaction times. Applying this new methodology two widely used anticoagulants phenprocoumon and coumatetralyl were synthesized applying mild reaction conditions. Georg Thieme Verlag Stuttgart New York.
- Rueping, Magnus,Nachtsheim, Boris J.,Sugiono, Erli
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experimental part
p. 1549 - 1553
(2010/08/22)
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- A general and efficient iron-catalyzed benzylation of 1,3-dicarbonyl compounds
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Various CH-acidic 1,3-dicarbonyl compounds and methyl 3-acetamidobut-2- enoate react with benzylic alcohols to give the corresponding 2-benzylated products in good to excellent yield. Typically, reactions proceed under mild conditions (50-80°C; air) in the presence of catalytic amounts of inexpensive iron chloride hexahydrate. The benzylation of 4-hydroxycoumarin gives the pharmaceutically interesting 4-hydroxy-3-(1-phenylethyl)-2H-chromen-2- ones. As an example the anticoagulant Phenprocoumon is prepared in one step from commercially available substrates in 94 % yield.
- Kischel, Jette,Mertins, Kristin,Michalik, Dirk,Zapf, Alexander,Beller, Matthias
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p. 865 - 870
(2008/03/18)
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- 4-HYDROXY-BENZOPYRAN-2-ONES AND 4-HYDROXY-CYCLOALKYL[B]PYRAN-2-ONES USEFUL TO TREAT RETROVIRAL INFECTIONS
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The present invention relates to compounds of formula I which are 4-hydroxy-benzopyran-2-ones and 4-hydroxy-cycloalkyl[b]pyran-2-ones useful for inhibiting a retrovirus in a mammalian cell infected with said retrovirus. STR1 Wherein R 10 and R 20 taken together are: STR2
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