3904-18-5Relevant academic research and scientific papers
Iron-Catalyzed Wacker-type Oxidation of Olefins at Room Temperature with 1,3-Diketones or Neocuproine as Ligands**
Kataeva, Olga,Kn?lker, Hans-Joachim,Linke, Philipp,Puls, Florian
supporting information, p. 14083 - 14090 (2021/05/24)
Herein, we describe a convenient and general method for the oxidation of olefins to ketones using either tris(dibenzoylmethanato)iron(III) [Fe(dbm)3] or a combination of iron(II) chloride and neocuproine (2,9-dimethyl-1,10-phenanthroline) as catalysts and phenylsilane (PhSiH3) as additive. All reactions proceed efficiently at room temperature using air as sole oxidant. This transformation has been applied to a variety of substrates, is operationally simple, proceeds under mild reaction conditions, and shows a high functional-group tolerance. The ketones are formed smoothly in up to 97 % yield and with 100 % regioselectivity, while the corresponding alcohols were observed as by-products. Labeling experiments showed that an incorporated hydrogen atom originates from the phenylsilane. The oxygen atom of the ketone as well as of the alcohol derives from the ambient atmosphere.
Green and simple preparation process of alpha-asarone
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Paragraph 0044-0047; 0054-0057, (2019/10/01)
The invention relates to the technical field of medicine, in particular to a green and simple preparation process of alpha-asarone. 1,2,4-trimethoxybenzene is adopted as a raw material, and three steps, namely, an acylation reaction, a reduction reaction and a dehydration reaction are included. Through the preparation process of alpha-asarone, the total yield can reach 62.3% or above, all organicsolvents can be recycled repeatedly, and the process has the advantages of low cost, small pollution, safe and convenient operation, high yield and the like.
Asymmetric Oxidation of Enol Derivatives to α-Alkoxy Carbonyls Using Iminium Salt Catalysts: A Synthetic and Computational Study
Page, Philip C. Bulman,Almutairi, Saud M.,Chan, Yohan,Stephenson, G. Richard,Gama, Yannick,Goodyear, Ross L.,Douteau, Alice,Allin, Steven M.,Jones, Garth A.
, p. 544 - 559 (2019/01/11)
We report herein the first examples of asymmetric oxidation of enol ether and ester substrates using iminium salt organocatalysis, affording moderate to excellent enantioselectivities of up to 98% ee for tetralone-derived substrates in the α-hydroxyketone products. A comprehensive density functional theory study was undertaken to interpret the competing diastereoisomeric transition states in this example in order to identify the origins of enantioselectivity. The calculations, performed at the B3LYP/6-31G(D) level of theory, gave good agreement with the experimental results, in terms of the magnitude of the effects under the specified reaction conditions, and in terms of the preferential formation of the (R)-enantiomer. Just one of the 30 characterized transition states dominates the enantioselectivity, which is attributed to the adoption of an orientation relative to stereochemical features of the chiral controlling element that combines a CH interaction between a CH2 group in the substrate and one of the aromatic rings of the biaryl section of the chiral auxiliary with a good alignment of the acetoxy group with the other biaryl ring, and places the smallest substituent on the alkene (a hydrogen atom) in the most sterically hindered position.
A new efficient method for the preparation of intermediate aromatic ketones by Friedel–Crafts acylation
Jin, Xiaojun,Wang, Ailing,Cao, Hongyu,Zhang, Shujia,Wang, Lihao,Zheng, Xueliang,Zheng, Xuefang
, p. 5521 - 5530 (2018/04/30)
Abstract: As the most important method to prepare pharmaceutical and chemical intermediate aromatic ketones, Friedel–Crafts (F–C) acylation is used to seek a novel catalytic system which is imminently consistent with the concept of green chemistry. In this study, six deep eutectic solvents (DES) were synthesized for the Friedel–Crafts acylation reaction as a catalytic solvent. Among the six DES, choline chloride-zinc chloride ([ChCl][ZnCl2]2) proved to be the most competent candidate of electron-rich arenes with acylation reagent. It got the highest yield when 1.0 equivalent of [ChCl][ZnCl2]2 used with acyl halides at 70?°C. Recycled DES was reused directly without any extra process. After five cycles, the catalytic activity did not decrease significantly (80–85%). Finally, according to experimental validation, the possible mechanism of this reaction was considered. Graphical Abstract: [Figure not available: see fulltext.].
Short Enantioselective Total Synthesis of Tatanan A and 3-epi-Tatanan A Using Assembly-Line Synthesis
Noble, Adam,Roesner, Stefan,Aggarwal, Varinder K.
supporting information, p. 15920 - 15924 (2016/12/16)
Short and highly stereoselective total syntheses of the sesquilignan natural product tatanan A and its C3 epimer are described. An assembly-line synthesis approach, using iterative lithiation–borylation reactions, was applied to install the three contiguo
Microwave- and ultrasound-assisted semisynthesis of natural methoxylated propiophenones from isomeric mixture of phenylpropenes in minutes
Joshi, Bhupendra P.,Sharma, Anuj,Sinha, Arun K.
, p. 1826 - 1832 (2007/10/03)
A rapid and practical semisynthesis of natural methoxylated propiophenones (3a-3f) is realized by reacting stereo- and regio-isomeric mixture of phenylpropenes (1a-1f) with a catalytic amount of palladium chloride - sodium formate in formic acid, methanol, and water (2:1:2) into single product phenylpropanes (2a-2f) followed by its oxidation with 2,3-dichloro-5,6- dicyanobenzoquinone (DDQ) in wet dioxane, containing a few drops of formic acid. Conventional, ultrasound, and microwave heating were compared through these studies.
Ultrasound-assisted convenient synthesis of hypolipidemic active natural methoxylated (E)-arylalkenes and arylalkanones
Joshi, Bhupendra P.,Sharma, Anuj,Sinha, Arun K.
, p. 3075 - 3080 (2007/10/03)
An ultrasound-assisted convenient method was developed for the conversion of toxic methoxylated cis-isomer of arylalkenes into its hypolipidemic active trans-isomer. Treatment of cis-isomer or mixture of all three isomers (1a-1j) with ammonium formate and 10% Pd/C gave arylalkanes (2a-2j), which upon oxidation with DDQ in anhydrous dioxane containing a little amount of silica gel, provided (E)-arylalkenes (3a-3g) in 42-72% yield depending upon the substituents attached at the aryl ring. The same method, upon addition of a few drops of water, provided hypolipidemic active arylalkanones (3h-3j) in 59-65% yield.
A mechanistic deviation in the Bischler indole synthesis
Sanchez-Viesca,Gomez,Berros, Martha
, p. 367 - 372 (2007/10/03)
When α-bromo-2,4,5-trimethoxybutyrophenone reacted with p-toluidine, the unexpected 3,5-dimethyl-2-(2,4,5-trimethoxybenzyl)indole was obtained. This mechanistic deviation was also observed with α -bromo-2,4,5-trimethoxyvalerophenone and α -bromo-2,4,5-tri
Process for the preparation of pharmacologically active α-asarone from toxic β-asarone rich acorus calamus oil
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, (2008/06/13)
The present invention relates to a process for the preparation of high purity and yield α-asarone, trans 2,4,5-trimethoxy cinnamaldehyde, 2,4,5-trimethoxy-phenyl propionone, from β-asarone or β-asarone rich Acorus calamus oil containing α and γ-asarone by hydrogenating, followed by treatment with DDQ with or without solid support of silica gel or alumina in dry organic solvent and α-asarone can also be obtained by treating the hydrogenated product of β-asarone or β-asarone rich Acorus calamus with DDQ in an aqueous organic solvent to obtain an intermediate 2,4,5-trimethoxy phenyl propionone, which in turn is reduced with sodiumborohydride to obtain the corresponding 2,4,5-trimethoxy-phenyl propanol and followed by final treatment with a dehydrating agent.
A PROCESS FOR THE PREPARATION OF PHARMACOLOGICALLY ACTIVE ALPHA-ASARONE FROM TOXIC BETA-ASARONE RICH ACORUS CALAMUS OIL
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Page/Page column 22, (2008/06/13)
The present invention relates to a process for the preparation of high purity and yield α-asarone, trans 2,4,5-trimethoxy cinnamaldehyde, 2,4,5-trimethoxy-phenyl propionone, from β-asarone or β-asarone rich Acorus calamus oil containing α and γ-asarone by hydrogenating, followed by treatment with DDQ with or without solid support of silica gel or alumina in dry organic solvent and α-asarone can also be obtained by treating the hydrogenated product of β-asarone or β-asarone rich Acorus calamus with DDQ in an aqueous organic solvent to obtain an intermediate 2,4,5-trimethoxy phenyl propionone, which in turn is reduced with sodiumborohydride to obtain the corresponding 2,4,5-trimethoxy-phenyl propanol and followed by final treatment with a dehydrating agent.
