- Gold(I)-Catalyzed Intramolecular Hydroarylation of Phenol-Derived Propiolates and Certain Related Ethers as a Route to Selectively Functionalized Coumarins and 2 H-Chromenes
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Methods are reported for the efficient assembly of a series of phenol-derived propiolates, including the parent system 56, and their Au(I)-catalyzed cyclization (intramolecular hydroarylation) to give the corresponding coumarins (e.g., 1). Simple syntheses of natural products such as ayapin (144) and scoparone (145) have been realized by such means, and the first of these subject to single-crystal X-ray analysis. A related process is described for the conversion of propargyl ethers such as 156 into the isomeric 2H-chromene precocene I (159), a naturally occurring inhibitor of juvenile hormone biosynthesis.
- Cervi, Aymeric,Vo, Yen,Chai, Christina L. L.,Banwell, Martin G.,Lan, Ping,Willis, Anthony C.
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p. 178 - 198
(2020/12/22)
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- Method for synthesizing ultraviolet ray absorber UV-0 through solid acid catalysis
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The invention provides a method for synthesizing an ultraviolet ray absorber UV-0 through solid acid catalysis. The method comprises the following steps that benzoic acid, resorcinol and phosphotungstic acid are added into a container, heating is conducted in an oil bath to 110-140 DEG C, stirring is conducted for a reaction for 5-24 hours, it is monitored that the reaction is completed through thin layer chromatography, after cooling, toluene is added for dissolving the product, and solid catalyst phosphotungstic acid is subjected to suction filtration and recycled; a residue obtained throughevaporation of a filtrate is recrystallized with methanol/water to obtain pale yellow solid, namely the ultraviolet ray absorber UV-0. By means of the process, the yield of the UV-0 is greater than 96%.
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Paragraph 0021; 0023
(2018/11/10)
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- Thermally Induced Denitrogenative Annulation for the Synthesis of Dihydroquinolinimines and Chroman-4-imines
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A rapid growth in synthetic methods for the preparation of diverse organic molecules using N-sulfonyl-1,2,3-triazoles is of great interest in organic synthesis. Transition metals are generally used to activate the α-imino diazo intermediates. Metal-free methods have not been studied in detail, but can be a good complement to transition metal catalysis in the mild reaction conditions. We herein report a novel method for the preparation of 2,3-dihydroquinolin-4-imine and chroman-4-imine analogs from their corresponding N-sulfonyl-1,2,3-triazoles in the absence of metal catalysts. To achieve intramolecular annulation, the introduction of an electron-donating group is required at the meta position of N-sulfonyl-1,2,3-triazole methyl anilines. The inclusion of tailored substituents on the aniline moieties and nitrogen atoms enhances the nucleophilicity of the phenyl π-electrons, thus allowing them to undergo a Friedel-Crafts-type reaction with the highly electrophilic ketenimines. This metal-free method was carefully optimized to generate a variety of dihydroquinolin-4-imines and chroman-4-imines in moderate-to-good yields.
- Chou, Chih-Hung,Chen, Ying-Yu,Rajagopal, Basker,Tu, Hsiu-Chung,Chen, Kuan-Lin,Wang, Sheng-Fu,Liang, Chien-Fu,Tyan, Yu-Chang,Lin, Po-Chiao
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supporting information
p. 757 - 765
(2016/03/09)
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- Synthesis of industrially important aromatic and heterocyclic ketones using hierarchical ZSM-5 and Beta zeolites
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Hierarchical ZSM-5 and Beta zeolites were investigated in the synthesis of wide range of industrially important aromatic/heterocyclic ketones by Friedel-Crafts acylation and benzoylation reactions. For comparative study, conventional ZSM-5 and Beta, and amorphous mesoporous Al-MCM-41 were investigated. Hierarchical zeolites were prepared by multi-ammonium structure directing agents whereas conventional zeolites were prepared by mono-ammonium structure directing agents. Among the catalysts investigated in this study, hierarchical Beta exhibited the highest reactant conversion in the acylation and benzoylation reactions. In this study, the systematic assessment of the catalytic activity of acid catalysts for wide range of aromatic and heterocyclic compounds is shown under one umbrella. To the best of our knowledge, these reactions over hierarchical zeolites (ZSM-5 and Beta) are reported here for the first time. Structure activity relationship is explained based on the physico-chemical properties, molecular size, reactivity of reactants, and reaction mechanism. Catalysts can be easily recovered and reused with negligible loss in the catalytic activity.
- Kore, Rajkumar,Srivastava, Rajendra,Satpati, Biswarup
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p. 129 - 141
(2015/09/28)
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- Design, synthesis and structure-activity relationship of new HSL inhibitors guided by pharmacophore models
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Hormone-sensitive lipase (HSL) is a critical enzyme involved in the hormonally regulated release of fatty acids and glycerol from adipocyte lipid stores. Its inhibition may improve insulin sensitivity and blood glucose handling in type 2 diabetes. Accordingly, many small-molecule HSL inhibitors have recently been identified. In continuation of our efforts for discovery of new HSL inhibitors, we prepared a variety of esters, amides, sulfonamides and sulfonate esters capable of fitting two pharmacophore models that we developed and published earlier. The tested compounds were synthesized via coupling reactions of aroyl chlorides or sulfonyl chlorides with phenols, amines and related derivatives. Our efforts led to the identification of interesting compounds of low micromolar anti-HSL bioactivities, which have potential to be developed into effective antidiabetic agents.
- Al-Shawabkeh, Jumana D.,Al-Nadaf, Afaf H.,Dahabiyeh, Lina A.,Taha, Mutasem O.
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p. 127 - 145
(2014/03/21)
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- HF-Pyridine: A versatile promoter for monoacylation/sulfonylation of phenolic diols and for direct conversion of t-butyldimethylsilyl ethers to the corresponding acetates
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Monoacylation and trifluoromethanesulfonylation of phenolic diols were achieved by the aid of HF-pyridine, whereas diacylation occurred with pyridine alone. Furthermore, HF-pyridine was found to promote the direct conversion of t-butyldimethylsilyl ethers to the corresponding acetates.
- Michigami, Kyosuke,Yoshimoto, Kazuya,Hayashi, Masahiko
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scheme or table
p. 138 - 139
(2012/03/09)
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- Construction of divergent anthracene arrays within dendritic frameworks
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This publication presents simple methodologies for construction of divergent anthracene arrays either within structural interior or at peripheral positions of dendritic frameworks. The synthetic approaches employed multiple coupling reactions between two types of 10-functionalized 9-anthryl chlorides and two types of polyphenolic linkers, resulting in four types of dendritic architectures. Successful implementation of the syntheses was confirmed by a range of spectroscopies along with elemental analyses and size exclusion chromatography studies. The resulting dendritic molecules showed a range of solubilities in chloroform fairly affected by the dendritic backbone structures. Fluorescence spectroscopic experiments of the multichromophoric dendritic systems indicated pronounced energy delocalization functionalities via an energy migration within the branched molecular frameworks as expressed in reduced fluorescence quantum yields and complex emission decay profiles.
- Takahashi, Masaki,Morimoto, Hironao,Suzuki, Yousuke,Yamashita, Mitsuji,Kawai, Hideki,Sei, Yoshihisa,Yamaguchi, Kentaro
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p. 3065 - 3074
(2007/10/03)
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- Quinoxalines. Part 13: Synthesis and mass spectrometric study of aryloxymethylquinoxalines and benzo[b]furylquinoxalines
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A series of new aryloxymethylquinoxalines, benzo[b]- and naphtho[2,1-b]furylquinoxalines, possessing potential biological activity, was prepared, characterized by IR and NMR spectroscopy and their electron ionization (EI) mass spectra studied in detail. The aryloxymethylquinoxalines were obtained by reacting halogenomethylquinoxalines with bifunctional O-nucleophiles. The benzo[b]furylquinoxalines and naphtho[2,1-b] furylquinoxalines were prepared via two routes, which differed in the order of the two cyclization steps involved in the syntheses. The composition of the ions obtained by EI mass spectrometry were determined by accurate mass measurements and the fragmentation pathways clarified by B/E linked scans and collision induced dissociation. The mass spectrometric behaviour of the compounds studied as to the possible loss of OH· radicals proved to be very characteristic.
- Starke, Ines,Sarodnick, Gerhard,Ovcharenko, Vladimir V.,Pihlaja, Kalevi,Kleinpeter, Erich
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p. 6063 - 6078
(2007/10/03)
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- PhCOCI-Py/basic alumina as a versatile reagent for benzoylation in solvent-free conditions
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A solvent-free procedure using PhCOCl-Py/basic alumina under microwave irradiation has been developed for N-, O- and S-benzoylation.
- Paul, Satya,Nanda, Puja,Gupta, Rajive
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p. 374 - 380
(2007/10/03)
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- Lipase PS-C catalysed hydrolysis of aryl diesters: A new route to the synthesis of achiral half esters
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Pseudomonas cepacia lipase supported on ceramic particles (PS-C) offers a simple alternative route for the synthesis of achiral half esters, with very high yields, easy work up and remarkable substrate selectivity, as it cleaves only phenolic esters having a phenyl group (i.e. C6H5-O-CO-C6H5).
- Nair, Ranjeet V.,Shukla, Manojkumar R.,Patil, Prashant N.,Salunkhe, Manikrao M.
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p. 1671 - 1677
(2007/10/03)
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- Process for the preparation of polyhydroxybenzophenones
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The invention relates to a process for the preparation of polyhydroxybenzophenones by treating benzoic acid or a derivative thereof with a polyhydroxybenzene or a derivative thereof in the presence of a large pore zeolite as a catalyst.
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- HYDROXYLATION DIRECTE D'ESTERS DE PHENYLE ET D'ANILIDES PAR LE PEROXYDE D'HYDROGENE EN MILIEU SUPERACIDE
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In SbF5-HF, hydrogen peroxide reacts on the aromatic ring of esters 1a-5a and anilides 11a-15a to give monohydroxylated derivatives in good yields.With compounds 2a, 4a and 5a, meta or para isomers are by far the major products, whereas with formate 1a and benzoate 3a, the proportion of the ortho isomer is more important.With anilides, the reaction is less selective, the three isomers being obtained in comparable amounts.Thus, the relative proportions of ortho, meta and para-hydroxylated derivatives obtained using 70 percent H2O2 with acetate 2a and acetanilide 12a are 6/51/43 and 36.5/30/33.5, respectively.The important proportion of meta hydroxylation is the result of the reaction of protonated hydrogen peroxide H3O2+ on the protonated substrate.
- Berrier, Christian,Jacquesy, Jean-Claude,Jouannetaud, Marie-Paule,Morellet, Guy
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p. 158 - 164
(2007/10/02)
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- Selective Aminolysis of Benzoates and Acetates of α-Hydroxy Acids and Phenols with Benzylamine and Butan-1-amine
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Benzoates and acetates of α-hydroxy acids and phenols undergo facile aminolysis on treating with benzylamine or butan-1-amine in benzene at room temperature.Under the same conditions acetates and benzoates of alcohols are unaffected.
- Bell, Kevin H.
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p. 1723 - 1735
(2007/10/02)
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