- Chemical conversion of β-O-4 lignin linkage models through Cu-catalyzed aerobic amide bond formation
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Methods for conversion of the lignin β-O-4 models into amide derivatives and phenols have been developed, which is achieved via chemo-selective oxidation of the secondary benzylic alcohol and subsequent Cu-catalyzed aerobic amide bond formation.
- Zhang, Jian,Liu, Yu,Chiba, Shunsuke,Loh, Teck-Peng
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Read Online
- Palladium-Catalyzed Chlorocarbonylation of Aryl (Pseudo)Halides Through In Situ Generation of Carbon Monoxide
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An efficient palladium-catalyzed chlorocarbonylation of aryl (pseudo)halides that gives access to a wide range of carboxylic acid derivatives has been developed. The use of butyryl chloride as a combined CO and Cl source eludes the need for toxic, gaseous carbon monoxide, thus facilitating the synthesis of high-value products from readily available aryl (pseudo)halides. The combination of palladium(0), Xantphos, and an amine base is essential to promote this broadly applicable catalytic reaction. Overall, this reaction provides access to a great variety of carbonyl-containing products through in situ transformation of the generated aroyl chloride. Combined experimental and computational studies support a reaction mechanism involving in situ generation of CO.
- Bismuto, Alessandro,Boehm, Philip,Morandi, Bill,Roediger, Sven
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supporting information
p. 17887 - 17896
(2020/08/19)
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- Frustrated Lewis Pair Catalyzed Hydrogenation of Amides: Halides as Active Lewis Base in the Metal-Free Hydrogen Activation
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A method for the metal-free reduction of carboxylic amides using oxalyl chloride as an activating agent and hydrogen as the final reductant is introduced. The reaction proceeds via the hydrogen splitting by B(2,6-F2-C6H3)3 in combination with chloride as the Lewis base. Density functional theory calculations support the unprecedented role of halides as active Lewis base components in the frustrated Lewis pair mediated hydrogen activation. The reaction displays broad substrate scope for tertiary benzoic acid amides and α-branched carboxamides.
- Sitte, Nikolai A.,Bursch, Markus,Grimme, Stefan,Paradies, Jan
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supporting information
p. 159 - 162
(2019/01/04)
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- Straightforward α-Amino Nitrile Synthesis Through Mo(CO)6-Catalyzed Reductive Functionalization of Carboxamides
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The selective reduction of amides into an intermediate hemiaminal catalyzed by Mo(CO)6 together with the inexpensive and easy to handle TMDS (1,1,3,3-tetramethyldisiloxane) as reducing agent, followed by subsequent trapping of the hemiaminal with a cyanide source, allows for the straightforward synthesis of α-amino nitriles. The methodology presented here, displays high levels of chemoselectivity allowing for the reduction of amides in the presence of functional groups such as ketones, imines, aldehydes, and acids, which affords a simple route for the synthesis of α-amino nitriles with a broad scope of functionalities in high yields. Furthermore, the applicability of this methodology is demonstrated by scale up experiments and by derivatization of the target compounds into synthetically interesting products. The selective cyanation is successfully applied in late stage functionalizations of amide containing drugs and prolinol derivatives.
- Trillo, Paz,Slagbrand, Tove,Adolfsson, Hans
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supporting information
p. 12347 - 12351
(2018/09/10)
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- Metal–Organic Framework Based on Copper and Carboxylate-Imidazole as Robust and Effective Catalyst in the Oxidative Amidation of Carboxylic Acids and Formamides
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A metal–organic framework (MOF) based on copper and 1,3-bis(carboxymethyl)imidazole (bcmim) was prepared on a gram scale by using a precipitation method at room temperature. The Cu(bcmim)2MOF was shown to be an efficient catalyst for the preparation of amides through an oxidative coupling between carboxylic acids and formamides in the presence of an oxidant, such as tert-butyl hydroperoxide (TBHP). The method for the preparation of the amides is robust regardless of the carboxylic acid and gives good conversions with good selectivity. The heterogeneous catalyst was recovered unaltered after the reaction, was easily separated from the reaction mixture, and subsequently reactivated by suitable treatment. Moreover, the coupling reaction was scaled up to a gram scale, which allowed for the preparation of valuable products, such as fatty acid amides (i.e., 1-palmitoylpiperidine).
- Albert-Soriano, María,Pastor, Isidro M.
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supporting information
p. 5180 - 5188
(2016/10/26)
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- Synthesis, crystal structure and anti-fatigue effects of some benzamide derivatives
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A series of benzamide derivatives such as 1-(1,3-benzodioxol-5-ylcarbonyl) piperidine (1-BCP) were synthesized by the reaction of substituted benzoic acids with piperidine, morpholine or pyrrolidine using a novel method. The crystals of these benzamide de
- Wu, Xianglong,Fan, Wutu,Pan, Yalei,Zhai, Yuankun,Niu, Yinbo,Li, Chenrui,Mei, Qibing
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p. 1034 - 1046
(2014/02/14)
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- Palladium nanoparticles supported on ZIF-8 as an efficient heterogeneous catalyst for aminocarbonylation
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Pd nanoparticles supported on ZIF-8 (PdNPs/ZIF-8) are described as an efficient heterogeneous catalyst for the aminocarbonylation of bromoarenes in the presence of phosphines and iodoarenes under phosphine-free conditions. The catalyst can be readily prepared and is air-stable. The palladium loading can be as low as 1 wt %, and the catalyst was recycled four times with negligible change in catalytic performance. A variety of pharmaceutically important amides was readily synthesized. A TON of 2540 was easily achieved in a batch reaction by scaling up to a gram scale. The catalyst reported can also be applied to the synthesis of cyclic and primary amides as well as an alkoxycarbonylation reaction to form an ester.
- Dang, Tuan T.,Zhu, Yinghuai,Ngiam, Joyce S. Y.,Ghosh, Subhash C.,Chen, Anqi,Seayad, Abdul M.
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p. 1406 - 1410
(2013/07/26)
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- Hansch analysis of veratric acid derivatives as antimicrobial agents
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The synthesis, characterization and antimicrobial evaluation of a new series of veratric acid derivatives are presented. Preliminary in vitro antimicrobial activity of the title compounds was assessed against a panel of microorganisms including Gram-positive and Gram-negative bacteria and fungi. Some of the veratric acid derivatives exhibited significant in vitro antimicrobial activity. QSAR investigation applied to find a correlation between different physicochemical parameters of the veratric acid derivatives and their antimicrobial activity indicated the importance of topological parameters in describing the antimicrobial activity.
- Narasimhan, Balasubramanian,Ohlan, Sucheta,Ohlan, Ruchita,Judge, Vikramjeet,Narang, Rakesh
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experimental part
p. 689 - 700
(2009/09/08)
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- Radical mediated-direct conversion of aldehydes into acid bromides
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A method of preparing acid bromides directly from aldehydes with Br3CCO2Et under radical conditions was developed. Aromatic aldehydes with electron-donating group were found to be more reactive than aromatic aldehydes with electron-w
- Kang, Dong Ho,Joo, Tae Young,Chavasiri, Warinthorn,Jang, Doo Ok
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p. 285 - 287
(2007/10/03)
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- Manipulation of substituents at nitrogen in tropanes, homotropanes, and dehydro- derivatives
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Trop-6-ene (8-methyl-8-azabicyclo[3.2.1]oct-6-ene) and substituted N- benzylnortrop-6-enes are synthesised. N-Debenzylation of tropanes fails using a wide variety of non-hydrogenolytic conditions despite effective application in model piperidine derivatives; debenzylation of homotropanes is more successful, giving norhomotropane and norhomotrop-7-ene. Bridged N-benzyl compounds react more slowly than N-methyl analogues with chloroformates; the resulting quaternary intermediates are more prone than the N-methyl analogues to suffer competitive reversion to the starting amine, especially in the tropanes, consistent with slower S(N)2 attack at the benzylic carbon during decomposition; the use of an N-p-methoxybenzyl group does allow partial debenzylation to nortrop-6-ene, suggesting greater S(N)1 character in the decomposition step in this case. 'Equatorial' attack is preferred in methylation of N-benzyl-nortrop-6-ene and -homotrop-7-ene with CH3I; subsequent reductive debenzylation of the quaternary salt achieves overall replacement of N-benzyl by N-methyl in both cases. VT NMR studies show the presence of a single 'equatorial' invertomer (CI syn- to the 2C-bridge) in N- chloro-norhomotropanes and -7-enes and by analogy, in the N-alkyl compounds.
- Howarth, Nicola M.,Malpass, John R.,Smith, Craig R.
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p. 10899 - 10914
(2007/10/03)
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