6876-64-8Relevant academic research and scientific papers
Catalyst-Free Singlet Oxygen-Promoted Decarboxylative Amidation of α-Keto Acids with Free Amines
Xu, Wen-Tao,Huang, Bei,Dai, Jian-Jun,Xu, Jun,Xu, Hua-Jian
, p. 3114 - 3117 (2016/07/14)
A novel catalyst-free decarboxylative amidation of α-keto acids with amines under mild conditions has been developed. Advantages of the new protocol include avoidance of metal catalysts and high levels of functional group tolerance. In addition, the reaction can be scaled up and shows high chemoselectivity. Preliminary mechanistic studies suggest that singlet oxygen, generated from oxygen under irradiation, is the key promoter for this catalyst-free transformation.
Analysis of intermolecular interactions involving halogens in substituted benzanilides
Chopra,Guru Row
, p. 133 - 141 (2007/10/03)
Crystal structures of halogen-substituted benzanilides have been analyzed in terms of weak interactions involving halogens. The four compounds namely 3-fluoro-N-(3-hydroxyphenyl)benzamide, 3-chloro-N-(3-hydroxyphenyl)benzamide, 3-fluoro-N-(4-methylphenyl)
Intramolecular charge transfer with N-benzoylaminonaphthalenes. 1-Aminonaphthalene versus 2-aminonaphthalene as electron donors
Zhang, Xuan,Liu, Chun-Hua,Liu, Li-Hong,Wu, Fang-Ying,Guo, Lin,Sun, Xiang-Ying,Wang, Chao-Jie,Jiang, Yun-Bao
, p. 728 - 732 (2007/10/03)
N-(substituted-benzoyl)-1-aminonaphthalenes and N-(substituted-benzoyl)-2-aminonaphthalenes (1-NBAs and 2-NBAs) with varied substituents at the para- or meta-position of benzoylphenyl ring were prepared to probe the difference between 1-aminonaphthalene (1-AN) and 2-aminonaphthalene (2-AN) as electron donors, using benzanilide-like charge transfer as a probe reaction. An abnormal long-wavelength emission was found for all of the prepared aminonaphthalene derivatives in cyclohexane and was assigned to the CT state by the observation of a substantial red shift with increasing solvent polarity or with increasing electron-withdrawing ability of the substituent. The CT emission energies were found to follow a linear relationship with the Hammett constant of the substituent and the value of the linear slope for 1-NBAs (-0.45 eV) was higher than that of 2-NBAs(-0.35 eV), the latter being close to that of the aniline derivatives (BAs, -0.345 eV). This pointed to a higher extent of charge separation in the CT state of 1-NBAs in which a full charge separation was established by the reduction potential dependence of the CT emission energy with a linear slope of -1.00. The possible contribution of the difference in the steric effect and the electron donating ability of the donors in 1-NBAs and 2-NBAs was ruled out by the observation that the corresponding linear slopes of benzoyl-substituted BAs remained unchanged when para-, meta-, ortho-, or ortho, ortho-methyls were introduced into the aniline moiety. It was therefore concluded that 1-AN enhanced the charge transfer in 1-NBAs and the proximity of its 1La and 1Lb states was suggested to be responsible. Results showed that the charge transfers in 1-NBAs and 2-NBAs were not the same and 1-AN and 2-AN as electron donors were different not only in electron donating ability but in shaping the charge transfer pathways as well.
Oxidative rearrangement of imines to formamides using sodium perborate
Nongkunsarn, Pakawan,Ramsden, Christopher A.
, p. 3805 - 3830 (2007/10/03)
Oxidation of C-aryl or alkyl-N-arylaldimines 6 or 20 by sodium perborate tetrahydrate (SPB) in trifluoroacetic acid solution gives rearranged N,N-disubstituted formamides 9 and 21. Yields are variable and solvent dependant with the best yields (50-60%) being obtained for electronically neutral C-aryl substituents or C-s-alkyl substituents. Product formation is rationalised in terms of an intermediate oxaziridine 5 that rearranges via acid catalysed O-N bond cleavage. An alternative C-O bond cleavage of these intermediates accounts for the formation of aldehydes, which are common by products. Rearrangement appears to be favoured by N-aryl substituents and by C-substituents that do not stabilise a developing positive charge on carbon. Further support for an oxaziridine intermediate 5 is provided by the observation that MCPBA oxidation of benzaldehyde phenylimine gives rearranged N,N-diphenylformamide. Under the conditions of the SPB oxidative rearrangements, oxaziridine formation may well occur by initial formation of trifluoroperacetic acid. Stereochemical aspects of this novel rearrangement of aldimines 1 → 2 have been investigated using trans- and cis-myrtanal 25 and 30. The observed epimerisation using die N-4-tolyl imine of trans-myrtanal 26 is believed to arise from equilibration of the precursor imine 26 with the tautomeric enamine 35b.
KINETICS AND MECHANISM OF THE AMINOLYSIS OF BENZOIC ANHYDRIDES
Lee, Byung Choon,Yoon, Ji Hyun,Lee, Cheal Gyu,Lee, Ikchoon
, p. 273 - 279 (2007/10/02)
Nucleophilic substitution reactions of benzoic anhydrides, in which one of the rings is substituted, with anilines were investigated in methanol.The product-formation step coincides with the rate-limiting step so that the two rate constants, kXY and kXZ, for the competitive reaction pathways can be dissected.The two cross-interaction constants, ρXY and ρXZ, especially an unusually large magnitude of the latter, indicate that the reaction proceeds by a frontside SN2 attack on either one of the carbonyl carbon with a strong interaction between the nucleophile (X) and the leaving group (Z).The mechanism is also supposed by the trends in the activation parameters.
An oxidative rearrangement of C,N-diarylaldimines to formamides using sodium perborate
Nongkunsarn, Pakawan,Ramsden, Christopher A.
, p. 6773 - 6776 (2007/10/02)
Treatment of C,N-diaryladium (5) with sodium tetrahydrate in triflouroacetic acid solution at 70-80° C results in an oxidative rearrangement to N,N-diarylformamides (6(Scheme 1). A mechanism involving the initial formation of 2,3-diaryloxaziridines is proposed (Scheme 2).
