- Method for preparing epsilon-caprolactone by using in-situ peroxide
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The invention discloses a method for preparing epsilon-caprolactone by using in-situ peroxide. The method efficiently utilizes an in-situ peroxide obtained in a process of oxidizing alcohol by oxygento oxidize cyclohexanone into epsilon-caprolactone, i.e., under the catalysis of a catalyst, an alcohol is oxidized into the corresponding ketone while substances such as peroxy hydroxyl or hydrogen peroxide and the like generated in the process are fully utilized, so that the Baeyer Villiger oxidation reaction from cyclohexanone to epsilon-caprolactone is realized. Compared with a previous epsilon-caprolactone synthesis method, the method of the invention has the advantages that the product yield is remarkably increased, the use efficiency of alcohol is further improved, raw materials and reagents are cheap and easy to obtain, operation is easy, reaction conditions are mild, and the method is clean and environmentally friendly.
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Paragraph 0053-0055
(2020/12/30)
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- Deacylative transformations of ketones via aromatization-promoted C–C bond activation
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Carbon–hydrogen (C–H) and carbon–carbon (C–C) bonds are the main constituents of organic matter. Recent advances in C–H functionalization technology have vastly expanded our toolbox for organic synthesis1. By contrast, C–C activation methods that enable editing of the molecular skeleton remain limited2–7. Several methods have been proposed for catalytic C–C activation, particularly with ketone substrates, that are typically promoted by using either ring-strain release as a thermodynamic driving force4,6 or directing groups5,7 to control the reaction outcome. Although effective, these strategies require substrates that contain highly strained ketones or a preinstalled directing group, or are limited to more specialist substrate classes5. Here we report a general C–C activation mode driven by aromatization of a pre-aromatic intermediate formed in situ. This reaction is suitable for various ketone substrates, is catalysed by an iridium/phosphine combination and is promoted by a hydrazine reagent and 1,3-dienes. Specifically, the acyl group is removed from the ketone and transformed to a pyrazole, and the resulting alkyl fragment undergoes various transformations. These include the deacetylation of methyl ketones, carbenoid-free formal homologation of aliphatic linear ketones and deconstructive pyrazole synthesis from cyclic ketones. Given that ketones are prevalent in feedstock chemicals, natural products and pharmaceuticals, these transformations could offer strategic bond disconnections in the synthesis of complex bioactive molecules.
- Xu, Yan,Qi, Xiaotian,Zheng, Pengfei,Berti, Carlo C.,Liu, Peng,Dong, Guangbin
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p. 373 - 378
(2019/05/22)
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- Acid fluorides as acyl electrophiles in suzuki–miyaura coupling
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The first palladium-catalyzed construction of ketones through Suzuki–Miyaura reaction by using acid fluorides is described. In contrast to typical acyl electrophiles such as acid chlorides, acid fluorides are uncommon acyl electrophiles to use in boron-based coupling reactions, probably due to a high level of stability toward nucleophiles. This first attempt to use acid fluorides as a coupling partner with boronic acids allowed highly functional group tolerance and a wide substrate scope while affording various ketones in effective yields.
- Ogiwara, Yohei,Sakino, Daisuke,Sakurai, Yuka,Sakai, Norio
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supporting information
p. 4324 - 4327
(2018/08/28)
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- A novel synthesis of [4-(3-methyl-1H-indol-2-yl) phenyl] (phenyl)methanone
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We have developed a simple route for the synthesis of [4-(3-methyl-1H-indol-2-yl)phenyl](phenyl)methanone from easily available starting materials. The (4-propylphenyl) phenylmethanone was prepared by Friedel Craft's benzoylation of n-propyl benzene with benzoyl chloride in dichloromethane using aluminium chloride as the Lewis acid catalyst. Side chain bromination with N-bromo succinimide in tetra chloro methane furnished the bromo derivative which on oxidation with bis-tetra butyl ammonium dichromate gave 1, 4-diacyl benzene. The target molecule was obtained through Fischer indole cyclisation of the diacyl benzene namely 1-(4-benzoylphenyl)propan-1-one via the formation of the hydrazone, followed by cyclization in presence of boron trifluoride ethyl etherate in acetic acid. The structure of the target molecule was elucidated by IR, H1, C13 NMR, Mass spectroscopy and elemental analysis. This method proves to be an efficient route for the synthesis of [4-(3-methyl-1H-indol-2-yl)phenyl](phenyl)methanone in high yields, thereby facilitating the generation of potential biologically active compounds.
- Suhana, Harindran,Rajeswari
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p. 3211 - 3217
(2018/01/17)
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- Erbium trifluoromethanesulfonate catalyzed Friedel-Crafts acylation using aromatic carboxylic acids as acylating agents under monomode-microwave irradiation
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Erbium trifluoromethanesulfonate is found to be a good catalyst for the Friedel-Crafts acylation of arenes containing electron-donating substituents using aromatic carboxylic acids as the acylating agents under microwave irradiation. An effective, rapid and waste-free method allows the preparation of a wide range of aryl ketones in good yields and in short reaction times with minimum amounts of waste.
- Tran, Phuong Hoang,Hansen, Poul Erik,Nguyen, Hai Truong,Le, Thach Ngoc
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p. 612 - 618
(2015/02/19)
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- Microwave-assisted facile and rapid friedel-crafts benzoylation of arenes catalyzed by bismuth trifluoromethanesulfonate
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The catalytic activity of metal triflates was investigated in Friedel-Crafts benzoylation under microwave irradiation. Friedel-Crafts benzoylation with benzoyl chloride of a variety of arenes containing electron-rich and electron-poor rings using bismuth triflate under microwave irradiation is described. This method allows the preparation of aryl ketones under solventless conditions in good to excellent yields and short reaction time. Bismuth triflate was easily recovered and reused five times without significant loss of the catalytic activity.
- Tran, Phuong Hoang,Hansen, Poul Erik,Pham, Thuy Thanh,Huynh, Vy Thanh,Huynh, Vy Hieu,Thi Tran, Thao Du,Huynh, Thanh Van,Le, Thach Ngoc
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p. 2921 - 2929
(2014/10/15)
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- Friedel-crafts benzoylation of alkylbenzenes with brazoic anhydride catalyzed by solid superacids
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The liquid-solid phase benzoylation of mono-alkylbenzenes with methyl, ethyl, propyl, and butyl groups and xylenes was carried out with benzoic anhydride at 100-110°C over solid superacids: SO4/ZrO 2, WO3/ZrO2, and SO4/ HfO 2. The reactivity ratio obtained by the competitive method of reaction over WO3/ZrO2 was 1 to 4.6 for toluene to p-xylene and 1.1:10:1 among o-, m-, and p-xylenes, respectively. Although the SO4/ZrO2 catalyst gave high yields of 92 and 97% for toluene and ethylbenzene in a 3:7 distribution of o- and p-isomers, respectively, low yields were observed with propyl and butylbenzenes over the catalyst: that is, 5 and 2% for propylbenzene and isopropylbenzene, 14% for isobutylbenzene, and trace yields for butylbenzene, s-butylbenzene, and t-butylbenzene, respectively. The usual Friedel-Crafts benzoylation using AlCl3 was examined in the present alkylbenzenes in order to confirm the low reactivity of both propyl and butylbenzenes. The results were similar to those with the SO4/ZrO2 catalyst; that is, the yields at 0°C for 1 h were 37, 21, 6, 1, 0, 3, and 2% for toluene, ethylbenzene, propylbenzene, isopropylbenzene, butylbenzene, s-butylbenzene, and t-butylbenzene, respectively, showing an unexpected result where there was no distinction between homogeneous and heterogeneous conditions.
- Nakamura, Hideo,Arata, Kazushi
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p. 1893 - 1896
(2007/10/03)
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- A facile synthesis of 1,4-diacylbenzenes
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An efficient method for the synthesis of 1,4-diacylbenzenes has been developed employing bis-tetrabutylammonium dichromate as an oxidant. By this methodology, a series of aldehydes and ketones have been synthesised under mild reaction conditions in moderate yields.
- Suhana, Harindran,Srinivasan, Panyencheri C.
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p. 3097 - 3102
(2007/10/03)
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