34855-33-9Relevant academic research and scientific papers
Microdroplets as Microreactors for Fast Synthesis of Ketoximes and Amides
Zhang, Wenwen,Yang, Shiwei,Lin, Qiuyu,Cheng, Heyong,Liu, Jinhua
, p. 851 - 859 (2019/01/24)
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.
o-Phthalic Anhydride/Zn(OTf)2 co-catalyzed Beckmann rearrangement under mild conditions
Xu, Ze-Feng,Zhang, Teng,Hong, Wenjun
supporting information, p. 3113 - 3117 (2019/05/08)
o-Phthalic anhydride/Zn(OTf)2 co-catalyzed Beckmann rearrangement was developed, producing the corresponding amide in up to 99% yield with acid-sensitive functionalities tolerated well, and the scale of the reaction could be enlarged to 77 mmol and the excellent yield was maintained. A successive procedure was developed. Moreover, the reaction was carried out at rt under nearly neutral conditions, and the workup was concise. These features illustrated the potential of the protocol in amide synthesis.
Hypervalent Iodine-Mediated Oxidative Rearrangement of N-H Ketimines: An Umpolung Approach to Amides
Zhao, Zhenguang,Peng, Zhiyuan,Zhao, Yongli,Liu, Hao,Li, Chongnan,Zhao, Junfeng
, p. 11848 - 11853 (2017/11/28)
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
Palladium-Catalyzed Carbonylative Synthesis of Amides from Aryltriazenes under Additive-Free Conditions
Yin, Zhiping,Wang, Zechao,Wu, Xiao-Feng
supporting information, p. 3992 - 3995 (2017/07/28)
An interesting palladium-catalyzed carbonylative synthesis of amides from aryltriazenes was developed. By using Pd(MeCN2)Cl2 as the catalyst precursor under CO pressure through a N2 extrusion/CO insertion sequence, a broad range of aryltriazenes were transformed into the corresponding amides in good yields with excellent functional group tolerance. Remarkably, no additives such as acids or phosphine ligands were required.
Crystal engineering of hand-twisted helical crystals
Saha, Subhankar,Desiraju, Gautam R.
supporting information, p. 1975 - 1983 (2017/02/15)
A strategy is outlined for the design of hand-twisted helical crystals. The starting point in the exercise is the one-dimensional (1D) plastic crystal, 1,4-dibromobenzene, which is then changed to a 1D elastic crystal, exemplified by 4-bromophenyl 4'-chlorobenzoate, by introduction of a molecular synthon -O-CO-in lieu of the supramolecular synthon Br···Br in the precursor. The 1D elastic crystals are next modified to two-dimensional (2D) elastic crystals, of the type 4-bromophenyl 4'-nitrobenzoate where the halogen bonding and C-H· · ·O hydrogen bonding are well-matched. Finally, varying the interaction strengths in these 2D elastic crystals gives plastic crystals with two pairs of bendable faces but without slip planes. Typical examples are 4-chlorophenyl and 4-bromophenyl 4'-nitrobenzoate. This type of 2D plasticity represents a new type of bendable crystals in which plastic behavior is seen with a fair degree of isotropic character in the crystal packing. The presence of two sets of bendable faces, generally orthogonal to each other, allows for the possibility of hand-twisting of the crystals to give grossly helical morphologies. Accordingly, we propose the name hand-twisted helical crystals for these substances.
Ligand- and Solvent-Tuned Chemoselective Carbonylation of Bromoaryl Triflates
Shen, Chaoren,Wei, Zhihong,Jiao, Haijun,Wu, Xiao-Feng
, p. 13369 - 1337 (2017/09/06)
The palladium-catalyzed chemoselective carbonylation of bromoaryl triflates is reported. The selective C?Br bond versus C?OTf (OTf=triflate) bond functionalization can be remarkably tuned by the combination of the ligand [4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (Xantphos) vs. 1,1′-bis(diphenylphosphino)ferrocene (DPPF)] and the solvent (toluene vs. DMSO). The respective ligand and solvent effects are rationalized by DFT calculations. In contrast, the monodentate ligands BuPAd2 and tBu3P prefer the selective C?Br bond activation and are solvent insensitive.
Convenient palladium-catalyzed aminocarbonylation of anilines to N-arylbenzamides
Wu, Xiao-Feng,Schranck, Johannes,Neumann, Helfried,Beller, Matthias
experimental part, p. 3702 - 3704 (2011/08/06)
The first one-pot diazotization/aminocarbonylation reaction of anilines to benzamides has been developed. In the presence of commercially available palladium acetate/P(o-Tolyl)3 as the catalyst system without base at low temperature (50°C) a variety of amides were synthesized in moderate to good yields.
Solid phase synthesis of amides using Mukaiyama's reagent
Tao, Bin,Boykin, David W.
, p. 10 - 11 (2007/10/03)
A new solid-phase synthetic method using Mukaiyama's reagent under mild conditions is reported to prepare amides in high purity without purification after cleavage from the resins.
