- Microdroplets as Microreactors for Fast Synthesis of Ketoximes and Amides
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The formation of amide bonds is one of the most valuable transformations in organic synthesis. Beckmann rearrangement is a well-known method for producing secondary amides from ketoximes. This study demonstrates the rapid synthesis of ketoximes and amides in microdroplets. Many factors are found to affect the yield, such as microdroplet generation devices, temperature, catalysts, and concentrations of reactants. In particular, the temperature has a great influence on the synthesis of amide, which is demonstrated by a sharp ascendance to the yield when the temperature was increased to 45 °C. The best amide yield (93.3%) can be obtained by using coaxial flowing devices, a sulfonyl chloride compound as a catalyst, and heating to 55 °C in microdroplets. The yields can reach 78.7-91.3% for benzoylaniline and 87.2-93.4% for benzophenone oximes in several seconds in microdroplets compared to 10.1-66.1% and 82.5-93.3% in several hours in the bulk phase. Apart from the dramatically decreased reaction time and enhanced reaction yields, the microdroplet synthesis is also free of severe reaction environments (anhydrous and anaerobic conditions). In addition, the synthesis in microdroplets also saves reactants and solvents and reduces the waste amounts. All of these merits indicate that the microdroplet synthesis is a high-efficiency green methodology.
- Zhang, Wenwen,Yang, Shiwei,Lin, Qiuyu,Cheng, Heyong,Liu, Jinhua
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p. 851 - 859
(2019/01/24)
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- Nickel/Briphos-Catalyzed Direct Transamidation of Unactivated Secondary Amides Using Trimethylsilyl Chloride
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Direct transamidation of secondary amides was developed via nickel catalysis. In the presence of trimethylsilyl chloride and manganese, Ni(diglyme)Cl2 with a Briphos ligand efficiently promoted the transamidation of N-aryl benzamide derivatives with primary amines to afford the corresponding secondary amides in moderate to good yields. Primary amines bearing electron-donating groups gave higher yields of the transamidation products.
- Yu, Subeen,Shin, Taeil,Zhang, Maosheng,Xia, Yuanzhi,Kim, Hyunwoo,Lee, Sunwoo
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supporting information
p. 7563 - 7566
(2019/01/03)
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- Rapidly Activating Pd-Precatalyst for Suzuki-Miyaura and Buchwald-Hartwig Couplings of Aryl Esters
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Esters are valuable electrophiles for cross-coupling due to their ubiquity and ease of synthesis. However, harsh conditions are traditionally required for the effective cross-coupling of ester substrates. Utilizing a recently discovered precatalyst, Pd-catalyzed Suzuki-Miyaura and Buchwald-Hartwig reactions involving cleavage of the C(acyl)-O bond of aryl esters that proceed under mild conditions are reported. The Pd(II) precatalyst is highly active because it is reduced to the Pd(0) active species more rapidly than previous precatalysts.
- Dardir, Amira H.,Melvin, Patrick R.,Davis, Ryan. M.,Hazari, Nilay,Mohadjer Beromi, Megan
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supporting information
p. 469 - 477
(2018/02/19)
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- Hypervalent Iodine-Mediated Oxidative Rearrangement of N-H Ketimines: An Umpolung Approach to Amides
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An umpolung approach to amides via hypervalent iodine-mediated oxidative rearrangement of N-H ketimines under mild reaction conditions is described. This strategy provides target amides with excellent selectivity in good yields. In addition, preliminary m
- Zhao, Zhenguang,Peng, Zhiyuan,Zhao, Yongli,Liu, Hao,Li, Chongnan,Zhao, Junfeng
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p. 11848 - 11853
(2017/11/28)
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- Lewis acid-assisted N-fluorobenzenesulfonimide-based electrophilic fluorine catalysis in Beckmann rearrangement
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A microwave-assisted N-fluorobenzenesulfonimide (NFSI)/Lewis acid-catalyzed Beckmann rearrangement was developed. The remarkable promotion to the electrophilicity of NFSI by Lewis acids was illustrated utilizing a series of readily available oxime substrates. The action model between NFSI and Lewis acids was probed by control experiments and theoretical calculations.
- Xie, Fukai,Du, Chuan,Pang, Yadong,Lian, Xu,Xue, Chentao,Chen, Yanyu,Wang, Xuefei,Cheng, Maosheng,Guo, Chun,Lin, Bin,Liu, Yongxiang
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p. 5820 - 5824
(2016/12/06)
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- DDQ-promoted direct transformation of benzyl hydrocarbons to amides via tandem reaction of the CDC reaction and Beckmann rearrangement
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An atom-efficient and transition metal-free approach to amides from the corresponding benzyl hydrocarbons through C-H and C-C bond cleavage has been developed. Mechanistic studies have shown that a DDQ-promoted cross-dehydrogenative coupling (CDC) reaction with subsequent oxidation and rearrangement are involved in this transformation. The Royal Society of Chemistry.
- Qiu, Jun,Zhang, Ronghua
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supporting information
p. 6008 - 6012
(2013/09/12)
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- The synthesis of N-arylated amides via copper(II) triflate-catalyzed direct oxygenation and N-arylation of benzylamines with aryl iodides
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An efficient approach for the synthesis of N-arylated amides by copper(II) triflate-catalyzed direct oxygenation and N-arylation reaction of benzylamines with aryl iodides is reported. Various benzylamines and aryl iodides can participate in the reaction, providing a series of N-arylated amides in moderate to good yields.
- Xu, Mei,Zhang, Xiao-Hong,Shao, Yin-Lin,Han, Jiang-Sheng,Zhong, Ping
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supporting information
p. 2665 - 2670,6
(2012/12/12)
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- The synthesis of N-arylated amides via copper(II) triflate-catalyzed direct oxygenation and N-arylation of benzylamines with aryl iodides
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An efficient approach for the synthesis of N-arylated amides by copper(II) triflate-catalyzed direct oxygenation and N-arylation reaction of benzylamines with aryl iodides is reported. Various benzylamines and aryl iodides can participate in the reaction, providing a series of N-arylated amides in moderate to good yields.
- Xu, Mei,Zhang, Xiao-Hong,Shao, Yin-Lin,Han, Jiang-Sheng,Zhong, Ping
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supporting information
p. 2665 - 2670
(2013/01/15)
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- Synthesis and evaluation of18F-labeled 2-phenylbenzothiazoles as positron emission tomography imaging agents for amyloid plaques in alzheimer's disease
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Imaging agents targeting amyloid β(Aβ) may be useful for early diagnosis and follow-up of treatment of patients with Alzheimer's disease (AD). Three of five tested 2-(4′-fluorophenyl)-1,3-benzothiazoles displayed high binding affinities for Aβ plaques in
- Serdons, Kim,Terwinghe, Christelle,Vermaelen, Peter,Van Laere, Koen,Kung, Hank,Mortelmans, Luc,Bormans, Guy,Verbruggen, Alfons
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experimental part
p. 1428 - 1437
(2009/12/26)
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- 1-Acyl-3-(amino-lower-alkyl)indoles
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1-Acyl-3-(amino-lower-alkyl)indoles, useful as anti-inflammatory agents, are prepared either by acylation of a 3-(amino-lower-alkyl)indole; by Fisher indole synthesis from an N'-acylphenylhydrazine and an amino-lower-alkanone; by alkylation of an amine with a 1-acyl-3-(halo-lower-alkyl)indole; or by reductive alkylation of a 1-acyl-3-indole-lower-alkylcarboxaldehyde.
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- 3-(Piperidino-lower-alkyl)-indoles
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1-Acyl-3-(amino-lower-alkyl)indoles, useful as anti-inflammatory agents, are prepared either by acylation of a 3-(amino-lower-alkyl)indole; by Fisher indole synthesis from an N'-acylphenylhydrazine and an amino-lower-alkanone; by alkylation of an amine with a 1-acyl-3-(halo-lower-alkyl)indole; or by reductive alkylation of a 1-acyl-3-indole-lower-alkylcarboxaldehyde.
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