13490-93-2Relevant academic research and scientific papers
Tandem Transformation of Aldoximes to N-Methylated Amides Using Methanol
Paul, Bhaskar,Maji, Milan,Panja, Dibyajyoti,Kundu, Sabuj
supporting information, p. 5357 - 5362 (2019/11/14)
Tandem conversion of aldoximes to N-methylated amides with methanol in presence of a single Ru(II) catalyst is accomplished through the Ru(II)-mediated rearrangement followed by the reductive N-methylation. Employing this protocol, several aldoximes were directly transformed to the N-methylated amides using methanol. Kinetic experiments with H218O advocated that the aldoxime is acted as the nucleophile during the aldoxime to amide rearrangement process. Involvement of nitrile intermediate during this transformation is realized from the kinetic study. (Figure presented.).
Atom-Economical and Tandem Conversion of Nitriles to N-Methylated Amides Using Methanol and Water
Paul, Bhaskar,Maji, Milan,Kundu, Sabuj
, p. 10469 - 10476 (2019/11/05)
A cobalt complex catalyzed tandem conversion of nitrile to N-methylated amide is described using a methanol and water mixture. Using this protocol, several nitriles were directly and efficiently converted to the desired N-methylated amides. Kinetic experiments using H2O18 and CD3OD suggested that water and methanol were the source of the oxygen atom and methyl group, respectively, in the final N-methylated amides. Importantly, the participation of active Co(I)-H species in this transformation was realized from the control experiment. The kinetic isotope effect (KIE) study suggested that the activation of the C-H bond of methanol was a kinetically important step. The Hammett plot confirmed that the reaction was faster with the electron deficient nitriles. In addition, the plausible pathway for the formation of N-methylated amides from the nitriles was supported by the computational study.
Ruthenium-Catalyzed Synthesis of N-Methylated Amides using Methanol
Paul, Bhaskar,Panja, Dibyajyoti,Kundu, Sabuj
supporting information, p. 5843 - 5847 (2019/08/26)
An efficient synthesis of N-methylated amides using methanol in the presence of a ruthenium(II) catalyst is realized. Notably, applying this process, tandem C-methylation and N-methylation were achieved to synthesize α-methyl N-methylated amides. In addition, several kinetic studies and control experiments with the plausible intermediates were performed to understand this novel protocol. Furthermore, detailed computational studies were carried out to understand the mechanism of this transformation.
Reaction pathway and rate-determining step of the Schmidt rearrangement/fragmentation: A kinetic study
Akimoto, Ryo,Tokugawa, Takehiro,Yamamoto, Yutaro,Yamataka, Hiroshi
experimental part, p. 4073 - 4078 (2012/06/29)
The Schmidt rearrangement of substituted 3-phenyl-2-butanone with trimethylsilyl azide in 90% (v/v) aqueous TFA gave two types of product, fragmentation and rearrangement, the ratio of which depends on the substituent: more fragmentation for a more electron-donating substituent. Rate measurements by azotometry indicated the presence of an induction period, and the pseudo-first-order rate constants showed saturation kinetics with respect to the azide concentration. It was indicated that the reaction proceeds through pre-equilibrium in the formation of iminodiazonium (ID) ion and that the N 2 liberation from the ID ion is rate-determining. Under high azide concentration conditions, where the effective reactant is the ID ion, the reaction gave a linear Hammett plot with a value of -0.50. The observed substituent effects on the rate and the product selectivity imply that path bifurcation on the way from the rate-determining TS to the product states occurs, as suggested by previous molecular dynamics simulations, in a similar manner to the analogous Beckmann rearrangement/fragmentation reactions.
Synthesis of α-amino amides via N,O-acetals derived from Weinreb amides
Hirner, Sebastian,Somfai, Peter
supporting information; experimental part, p. 7798 - 7803 (2009/12/29)
(Chemical Equation Presented) An easy and straightforward synthesis of α-amino amides via a base-mediated rearrangement of modified Weinreb amides into N,O-acetals is presented. Subsequent arylation, alkylation, alkenylation, or alkynylation of this intermediate affords the corresponding R-amino amides in excellent yields. Furthermore, a more generalized protocol for the α-arylation of Weinreb amides lacking an R-amino moiety is also discussed.
The ruthenium-catalyzed reduction and reductive N-alkylation of secondary amides with hydrosilanes: Practical synthesis of secondary and tertiary amines by judicious choice of hydrosilanes
Hanada, Shiori,Ishida, Toshiki,Motoyama, Yukihiro,Nagashima, Hideo
, p. 7551 - 7559 (2008/02/12)
(Chemical Equation Presented) A triruthenium cluster, (μ3, η2,η3,η5-acenaphthylene)Ru 3(CO)7 (1) catalyzes the reaction of secondary amides with hydrosilanes, yielding a mixture of secondary amines, tertiary amines, and silyl enamines. Production of secondary amines with complete selectivity is achieved by the use of higher concentration of the catalyst (3 mol %) and the use of bifunctional hydrosilanes such as 1,1,3,3-tetramethyldisiloxane. Acidic workup of the reaction mixture affords the corresponding ammonium salts, which can be treated with a base, providing a facile method for isolation of secondary amines with high purity. In contrast, tertiary amines are formed with high selectivity by using lower concentration of the catalyst (1 mol %) and polymeric hydrosiloxanes (PMHS) as reducing agent. Reduction with PMHS encapsulates the ruthenium catalyst and organic byproducts to the insoluble silicone resin. The two reaction manifolds are applicable to various secondary amides and are practical in that the procedures provide the desired secondary or tertiary amine as a single product. The product contaminated with only minimal amounts of ruthenium and silicon residues. On the basis of the products and observed side products as well as NMR studies a mechanistic scenario for the reaction is also described.
Hydroamidation of alkenes with N-substituted formamides
Nath, Dilip Chandra Deb,Fellows, Christopher M.,Kobayashi, Toshiaki,Hayashi, Teruyuki
, p. 218 - 224 (2008/02/02)
Hydroamidation of olefins with N-substituted formamides is performed with dodecacarbonyltriruthenium (Ru3(CO)12) at 180°C under N2 or CO atmosphere in toluene and in a series of ionic liquids. Yields of 99% with 94?97% exo selectivity are found in the addition of N-methylformamide to 2-norbornene under CO both in toluene and in the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [bmim][NTf2]. The presence of CO or a phosphine is necessary for significant reaction to occur, with CO more effective than triphenylphosphine in all ionic liquids investigated. Reasonable yields are achieved at low pressures, in contrast to most reported hydroamidations. Conversion, exo-selectivity, and selectivity fall with increasing steric bulk of the N-formamide substituent, and disubstituted formamides are inactive. Of the terminal alkenes investigated, only styrene can be hydroamidated. CSIRO 2006.
Study of the reactivity of α-acylenaminoketones. Synthesis of pyrazoles
Negri,Kascheres
, p. 109 - 123 (2007/10/03)
The reactions of 4-(methylamino)-3-penten-2-one with diazoketones yielded the α-acylenaminoketones 1-3 in good yields. Preparation of the α-acylenaminoketone 4 was carried out by treatment of 4-(t-butylamino)-3-penten-2-one with benzoyl chloride being followed by reaction of transamination with methylamine. The reactions were carried out in five different solvents and were submitted to gas chromatography/mass spectrometry analysis, with the goal of obtaining substituted pyrazoles and determining which of the carbonyls would preferentially be attacked by the nucleophile. The reactions of compounds 1-4 with hydrazine reagents led to the formation of the pyrazoles 5-7a-q. Small amounts of 4-methylamino-2-pentenones 10a-q, amides 11a-q and pyrazoles 12a-q were also obtained in these reactions. The unexpected formation of pyrazoles 15d,h,q was detected when methanol and N,N-dimethylformamide were used as solvents in the reactions of α-acylenaminoketone 4 with hydrazine reagents.
Principal Component Analysis on the effect of nucleophiles on the reactivity of α-acylenaminoketones
Kascheres, Concetta,Negri, Giuseppina,Ferreira, Marcia M.C.,Sabino, Luciana C.
, p. 2237 - 2243 (2007/10/03)
This report shows the importance of Principal Component Analysis for grouping types of products observed when α-acylenaminoketones K1-K3 react with four substituted hydrazine nucleophiles in five organic solvents. The reactions were carried out with the g
