- Synthesis method of p-acetoxystyrene
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The invention discloses a synthesis method of p-acetoxystyrene, which relates to the field of organic synthesis. The synthesis route of the synthesis method is as follows: 1, adding p-hydroxyacetophenone and an acetylation reagent into a first solvent, and carrying out esterification reaction under an alkaline condition to generate p-acetoxyacetophenone, 2, adding p-acetoxyacetophenone into a second solvent, and reducing the p-acetoxyacetophenone into 4-acetoxyphenyl methyl methanol under the catalysis of a catalyst in a hydrogen atmosphere, and 3, dehydrating the 4-acetoxyphenyl methyl methanol in an alkaline ionic liquid to obtain the p-acetoxystyrene. The method is high in yield, low in three wastes, green and clean, and the recovery cost and the equipment cost are reduced.
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- Preparation method of p-acetoxystyrene
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The invention relates to the field of organic chemistry, and in particular, relates to a preparation method of p-acetoxystyrene. The preparation method of p-acetoxystyrene provided by the invention comprises the steps: carrying out a reaction of p-hydroxyacetophenone with an acetylation reagent to prepare p-acetoxyacetophenone; carrying out hydrogenation reduction on p-acetoxyacetophenone to prepare 1-(4-acetoxyphenyl)ethanol; and carrying out an elimination reaction on 1-(4-acetoxyphenyl)ethanol to prepare p-acetoxystyrene. According to the preparation method of p-acetoxystyrene, starting from the most basic raw materials, three steps of reactions are carried out, especially in the third step of alkene formation reaction, alkaline elimination is creatively adopted, the defects that in traditional acid catalysis alkene formation elimination reaction, double-bond acid catalysis sudden side reactions are likely to happen, the reaction is likely to be out of control, and consequently theyield is low are overcome, and generated double bonds can stably exist for a long time in a reaction system.
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- A facile and highly efficient transfer hydrogenation of ketones and aldehydes catalyzed by palladium nanoparticles supported on mesoporous graphitic carbon nitride
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A novel transfer hydrogenation methodology for the reduction of ketones (14 examples) and benzaldehyde derivatives (12 examples) to the corresponding alcohols using Pd nanoparticles supported on mesoporous graphitic carbon nitride (mpg-C3N4/Pd) as a reusable catalyst and ammonia borane as a safe hydrogen source in an aqueous solution MeOH/H2O (v/v = 1/1) is described. The catalytic hydrogenation reactions were conducted in a commercially available high-pressure glass tube at room temperature, and the corresponding alcohols were obtained in high yields in 2–5 min. Moreover, the presented transfer hydrogenation protocol shows partial halogen selectivity with bromo-, fluoro-, and chloro-substituted carbonyl analogs. In addition, the present catalyst can be reused up to five times without losing its efficiency, and scaling-up the reaction enables α-methylbenzyl alcohol to be produced in 90% isolated yield.
- Ni?anc?, Bilal,Da?alan, Ziya
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- Oxygenation of styrenes catalyzed by N-doped carbon incarcerated cobalt nanoparticles
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NCI-Co catalyzed olefin oxygenation reactions were investigated. Among the metals examined, including noble metals, the reaction proceeded specifically on Co catalysts, and nitrogen dopant was crucial for the catalytic activity. The presence of NaBH4 as a hydride source, the corresponding alcohols were obtained in high yields. The substrates bearing a reductant-sensitive functional group were made tolerant by changing the reductant and using an additive, and furthermore, the corresponding ketones were accessed by changing reaction conditions. A preliminary examination of other SOMOphiles suggested that the heterogeneous catalyst systems have the potential to be applied to more general hydrofunctionalization of olefins to form various kinds of bonds. Several mechanistic studies suggested that the reaction proceeded in a heterogeneous manner and formed a radical intermediate on cobalt nanoparticle species.
- Yasukawa, Tomohiro,Kobayashi, Shū
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supporting information
p. 1980 - 1985
(2019/12/24)
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- Two-component boronic acid catalysis for increased reactivity in challenging Friedel-Crafts alkylations with deactivated benzylic alcohols
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A general and efficient boronic acid catalyzed Friedel-Crafts alkylation of arenes with benzylic alcohols was previously developed for the construction of unsymmetrical diarylmethane products (X. Mo, J. Yakiwchuk, J. Dansereau, J. A. McCubbin and D. G. Hall, J. Am. Chem. Soc., 2015, 137, 9694). Highly electron-deficient benzylic alcohols, however, were ineffective coupling partners due to the increased difficulty of C-O bond ionization. Herein, we report the use of perfluoropinacol as an effective co-catalyst to improve the reactivity of a boronic acid catalyst in the Friedel-Crafts benzylations of electronically deactivated primary and secondary benzylic alcohols. According to spectroscopic studies, it is believed that perfluoropinacol condenses with the arylboronic acid catalyst to form a highly electrophilic and Lewis acidic boronic ester. This in situ formed species enables a more facile ionization of the benzylic alcohols likely through a mode of activation promoted by a Lewis acid assisted hydronium Br?nsted acid generated from the interactions of the transient boronic ester with hexafluoroisopropanol solvent and water.
- Ang, Hwee Ting,Rygus, Jason P. G.,Hall, Dennis G.
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supporting information
p. 6007 - 6014
(2019/06/24)
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- Synthesis, structures, and transfer hydrogenation catalysis of bifunctional iridium complexes bearing a C-N chelate oxime ligand
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We have synthesized a series of organometallic oxime complexes as novel metal-ligand cooperating bifunctional catalysts. The reaction of [{Cp*IrCl(μ2-Cl)}2] with ketoximes in the presence of sodium acetate afforded the half-sandwich chlorido iridium complexes 6 bearing a C-N chelate oxime ligand with a protic OH group in the β-position to the metal. Complex 6a, derived from acetophenone oxime, reacted with silver triflate to give the triflate complex 7 and cationic nitrile complex 8 depending upon the reaction solvent. Complexes 6 also reacted with a base in dichloromethane to afford the oximato-bridged dinuclear complexes 9, which were converted back to the chlorido complexes 6 upon treatment with an amine hydrochloride. In contrast, dehydrochlorination of 6 in 2-propanol as well as the reaction of 9 with 2-propanol yielded the hydrido-bridged dinuclear oxime-oximato complexes 10. Crossover experiments revealed that 10 dissociates into the mononuclear hydrido-oxime complex 11 and unsaturated oximato complex 12, which are interconvertible by reactions with hydrogen donors and acceptors. Owing to the metal-ligand cooperation, 10 effectively catalyzed transfer hydrogenation of ketones with 2-propanol. Copyright
- Watanabe, Megumi,Kashiwame, Yohei,Kuwata, Shigeki,Ikariya, Takao
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experimental part
p. 504 - 511
(2012/03/11)
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- Candida tenuis xylose reductase catalysed reduction of acetophenones: The effect of ring-substituents on catalytic efficiency
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The catalytic efficiencies of Candida tenuis xylose reductase catalysed reductions of mono-substituted acetophenones are in reasonable correlation with the σ-Hammett coefficients of the substituted phenyl groups. Variations of the substrate transformation rates are hence mainly caused by mesomeric and inductive effects of the substituents, while differences in substrate binding have a secondary relevance. Some substrate 1H NMR chemical shifts and carbonyl IR absorption bands are in reasonable accordance with the catalytic activities and allow the estimation of the transformation rates with good accuracy. The resulting substituted (S)-1-phenyl ethanols are generated in very high enantiomeric excess.
- Vogl, Michael,Kratzer, Regina,Nidetzky, Bernd,Brecker, Lothar
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p. 5863 - 5870
(2011/09/30)
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- Secondary Benzylation Using Benzyl Alcohols Catalyzed by Lanthanoid, Scandium, and Hafnium Triflate
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The combination of a secondary benzyl alcohol and a metal triflate (e.g., La, Yb, Sc, and Hf triflate) in nitromethane was a highly effective secondary-benzylation system. Secondary benzylation of carbon (aromatic compounds, olefins, an enol acetate), nitrogen (amide derivatives), and oxygen (alcohols) nucleophiles was carried out with a secondary benzyl alcohol and 0.01-1 mol % of a metal triflate in the presence of water. Secondary benzyl alcohols and nucleophiles bearing acid-sensitive functional groups (e.g., tert-butyldimethylsilyloxy and acetoxy groups and methyl and benzyl esters) could be used for alkylation. Hf(OTf)4 was the most active catalyst for this alkylation, and trifluoromethanesulfonic acid (triflic acid, TfOH) was also a good catalyst. The catalytic activity of metal triflates and TfOH increased in the order La(OTf)3 3 3 4. A mechanistic study was also performed. The reaction of 1-phenylethanol (4a) in the presence of Sc(OTf) 3 in nitromethane gave an equilibrium mixture of 4a and bis(1-phenylethyl) ether (54). Addition of a carbon nucleophile to the equilibrium mixture gave alkylated product in high yield.
- Noji, Masahiro,Ohno, Tomoko,Fuji, Koji,Futaba, Noriko,Tajima, Hiroyuki,Ishii, Keitaro
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p. 9340 - 9347
(2007/10/03)
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- Germination and growth inhibitors from wheat (Triticum aestivum L.) husks
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On the basis of our findings that the germination of intact wheat seeds (with husks) belonging to dormancy varieties was restrained as compared with that of the dehusked seeds (grains), the germination inhibitors in the husks were explored. The water-soluble extracts from the husks were separated by the aid of inhibition assay experiments, resulting in the characterization of 2-phenylethyl alcohol 1, 4-vinylphenol 2 and its 2-methoxy derivative 3, and dihydroactinidiolide 4, all of which showed clear inhibition of germination at 500 ppm in aqueous solution. The related compounds 1-phenylethyl alcohol 5 and tetrahydroactinidiolide 6 were as active as 1 and 4, while no noticeable difference in activity was detected among both enantiomers and the DL-form of compounds 4-6. Clear synergistic relations were observed between 4 and 1 and also 4 and 3. Since the present inhibitors have been isolated from various kinds of seed plants, they may be responsible for the general germination inhibition in the seed plants.
- Kato, Tadahiro,Saito, Naoko,Kashimura, Kaori,Shinohara, Mariko,Kurahashi, Takuma,Taniguchi, Kohji
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p. 6307 - 6312
(2007/10/03)
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- Convenient and selective acetylations of phenols, amines and alcohols
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Two convenient methods have been developed for selective acetylation. In method 1, phenols and amines are selectively acetylated in the presence of alcohols by acetic anhydride in a biphasic aqueous NaOH-isopropanol mixture. In method 2, alcoholic group is acetylated in the presence of amino functions using a strong acidic resin.
- Srivastava,Tandon,Ray
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p. 2703 - 2710
(2007/10/02)
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- Synthesis of 4-acetoxystyrene oxide and related compounds
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A method is provided of producing 4-acetoxystyrene oxide and substituted 4-acetoxystyrene oxides wherein at least one of the ring hydrogen atoms is substituted with a C1 to C10 alkyl or alkoxy, amino, halogen or nitro, wherein 4-acetoxystyrene or the corresponding substituted 4-acetoxystyrene is epoxided with peracetic acid containing no more than a trace of a mineral acid or water. The invention also includes, as new compositions of matter, 3,5-dimethyl-4-acetoxystyrene oxide and 3,5-dibromo-4-acetoxystyrene oxide.
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- SELECTIVE REDUCTION OF KETOESTERS TO HYDROXYESTERS WITH THE USE OF LITHIUM ALUMINUM HYDRIDE IN THE PRESENCE OF SILICA GEL
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Lithium aluminum hydride, in the presence of a small amount of silica gel, has been found to be a versatile and highly selective reagent for reduction of various ketoesters to the corresponding hydroxyesters in fair yields.
- Kamitori, Yasuhiro,Hojo, Masaru,Masuda, Ryoichi,Inoue, Tatsuro,Izumi, Tatsuo
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p. 4585 - 4588
(2007/10/02)
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