5336-24-3Relevant academic research and scientific papers
Diverse Oxidative C(sp2)-N Bond Cleavages of Aromatic Fused Imidazoles for Synthesis of α-Ketoamides and N-(pyridin-2-yl)arylamides
Xu, Fangzhou,Wang, Yanyan,Xun, Xiwei,Huang, Yun,Jin, Zhichao,Song, Baoan,Wu, Jian
, p. 8411 - 8422 (2019/05/17)
An efficient and chemoselective C(sp2)-N bond cleavage of aromatic imidazo[1,2-a]pyridine molecules is developed. A broad scope of amide compounds such as α-ketoamides and N-(pyridin-2-yl)arylamides are afforded as the final products in up to quantitative yields. Diverse C-N bond cleavages are controlled by the oxidative species used in this transformation, with various amide products afforded in a chemoselective fashion. A preliminary study indicated that some α-ketoamides exhibit anti-Tobacco Mosaic Virus activity for potential use in plant protection.
Mechanistic Basis for Efficient, Site-Selective, Aerobic Catalytic Turnover in Pd-Catalyzed C-H Imidoylation of Heterocycle-Containing Molecules
Tereniak, Stephen J.,Stahl, Shannon S.
supporting information, p. 14533 - 14541 (2017/10/24)
A recently reported Pd-catalyzed method for oxidative imidoylation of C-H bonds exhibits unique features that have important implications for Pd-catalyzed aerobic oxidation catalysis: (1) The reaction tolerates heterocycles that commonly poison Pd catalysts. (2) The site selectivity of C-H activation is controlled by an N-methoxyamide group rather than a suitably positioned heterocycle. (3) A Pd0 source, Pd2(dba)3 (dba = dibenzylideneacetone), is superior to Pd(OAc)2 as a precatalyst, and other PdII sources are ineffective. (4) The reaction performs better with air, rather than pure O2. The present study elucidates the origin of these features. Kinetic, mechanistic, and in situ spectroscopic studies establish that PdII-mediated C-H activation is the turnover-limiting step. The tBuNC substrate is shown to coordinate more strongly to PdII than pyridine, thereby contributing to the lack of heterocycle catalyst poisoning. A well-defined PdII-peroxo complex is a competent intermediate that promotes substrate coordination via proton-coupled ligand exchange. The effectiveness of this substrate coordination step correlates with the basicity of the anionic ligands coordinated to PdII, and Pd0 catalyst precursors are most effective because they selectively afford the PdII-peroxo in situ. Finally, elevated O2 pressures are shown to contribute to background oxidation of the isonitrile, thereby explaining the improved performance of reactions conducted with air rather than 1 atm O2. These collective results explain the unique features of the aerobic C-H imidoylation of N-methoxybenzamides and have important implications for other Pd-catalyzed aerobic C-H oxidation reactions.
Stoichiometric Reactions of CO2 and Indium-Silylamides and Catalytic Synthesis of Ureas
Xu, Maotong,Jupp, Andrew R.,Stephan, Douglas W.
supporting information, p. 14277 - 14281 (2017/10/31)
The indium compounds In(N(SiMe3)2)2Cl?THF (2) and In(N(SiMe3)2)Cl2?(THF)n (3) were shown to react with CO2 to give [(Me3Si)2N)InX(μ-OSiMe3)]2 (X=N(SiMe3)2 4, Cl 5). 0.05–2.0 mol % of the species 3 acts as a pre-catalyst for the conversion of aryl and alkyl silylamines under CO2 (2–3 atm) to give the corresponding ureas in 70–99 % yields. A proposed mechanism is supported by experimental and computational data.
Synthesis of secondary amides from N-Substituted amidines by tandem oxidative rearrangement and isocyanate elimination
Debnath, Pradip,Baeten, Mattijs,Lefvre, Nicolas,Van Daele, Stijn,Maes, Bert U. W.
supporting information, p. 197 - 209 (2015/03/03)
In this work an efficient tandem process transforming N-substituted amidines into secondary amides has been described. The process involves N-acylurea formation by reaction of the substrate with bis(acyloxy)(phenyl)-λ3-iodane followed by isocyanate elimination. The periodinane reagents are obtained from the commercially available phenyl-iodine(III) diacetate [PhI(OAc)2, (PIDA)] by ligand exchange with carboxylic acids. The N-substituted amidine substrates are easily synthesized from readily available nitriles. The method is applicable for secondary amide synthesis, based on both aliphatic and (hetero)aromatic amines, including challenging amides consisting of sterically hindered acids and amines. Moreover, the protocol allows one to combine steric bulk with electron deficiency in the target amides (aniline based). Such compounds are difficult to synthesize efficiently based on classical condensation reactions involving carboxylic acids and amines. Overall, the synthetic protocol transforms a nitrile into a secondary amide in both aliphatic and (hetero)aromatic systems.
Synthesis of 2-aminobenzoxazoles and 3-aminobenzoxazines via palladium-catalyzed aerobic oxidation of o -aminophenols with isocyanides
Liu, Bifu,Yin, Meizhou,Gao, Hanling,Wu, Wanqing,Jiang, Huanfeng
supporting information, p. 3009 - 3020 (2013/06/26)
A Pd-catalyzed aerobic oxidation of o-aminophenols and isocyanides for the synthesis of 2-aminobenzoxazoles and 3-aminobenzoxazines has been achieved in an air atmosphere. The procedure constructs 2-aminobenzoxazoles and 3-aminobenzoxazines with moderate to excellent yields and a broad substrate scope. Apart from experimental simplicity, this methodology has the advantages of mild reaction conditions and easily accessible starting materials. Furthermore, the utility of this method has also been successfully applied to the synthesis of other types of useful nitrogen heterocycles.
Novel synthesis of diazetidine-2,4-dione by ring expansion of diaziridinone
Komatsu, Mitsuo,Tamabuchi, Satoshi,Minakata, Satoshi,Ohshiro, Yoshiki
, p. 67 - 70 (2007/10/03)
Treatment of N,N'-di-tert-butyldiaziridinone with Ni(CO)4 under an atmosphere of carbon monoxide caused a carbonylative ring expansion to give ditert-butyldiazetidinedione in good yield. In the presence of diphenylketene under the conditions, azetidinedione derivative was obtained.
N,N-Dialkylcarbodiimide synthesis by palladium-catalysed coupling of amines with isonitriles
Pri-Bar, Ilan,Schwartz, Jeffrey
, p. 347 - 348 (2007/10/03)
Catalytic condensation of amines and isonitriles can be accomplished efficiently at 100°C using a palladium complex catalyst, oxygen, and iodine to give N,N-dialkylcarbodiimides.
Metathesis and reduction reactions of nitroso compounds with metal carbenes and metal carbonyls
Herndon, James W.,McMullen, Leonard A.
, p. 83 - 102 (2007/10/02)
Reaction of nitroso compounds with metal-carbene complexes and metal carbonyls has been investigated.These reactions lead to reduction of the nitroso compounds, primarily to the corresponding azo- and azoxy compounds.Metal-nitrene complexes have been proposed as intermediates in these reactions.These intermediates couple rapidly with the unreacted nitroso compound, or enter into nitrene-like reactions with external or internal trapping agents.Reaction of metal carbonyls with nitrosoarenes and photolysis has been found to be an effective method for the reduction of nitrosoarenes to azoxyarenes, with few problems resulting from overreduction to amines or azo compounds.
ANIONIC ACTIVATION BY FLUORIDE ION IN SOLID-LIQUID SYSTEMS. SYNTHESIS OF 3 (2H)-FURANONES AND 2 (5H)-FURANONES.
Sebti, S.,Foucaud, A.
, p. 1361 - 1368 (2007/10/02)
The evolution of 2-acyloxy 2-methyl 3-oxobutanamides 1 and 2-acyloxy 3-oxo 2,3-diphenylpropanamides 13 under anionic activation by cesium fluoride was studied.The fluoride ion is an efficient base for the heterocyclization of 1 into 3 (2H)-furanones and 2 (5H)-furanones, but the hydrolysis of the ester group lowered the selectivity of the reaction.However, the cleavage of 13 into the esters 14 and the cyclization of 3-benzoyloxy 3-methyl 2-butanone into bullatenone are very selective.
