Stereochemistry of N-methylbenzanilide and benzanilide

Itai, Akiko; Toriumi, Yoshiharu; Tomioka, Nobuo; Kagechika, Hiroyuki; Azumaya, Isao; Shudo, Koichi

doi:10.1016/s0040-4039(01)93335-0

Cited by 172 publications

(84 citation statements)

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“…The final computed energies were used to calculate the Boltzmann distribution of the conformers in a THF solution. The preferred cis conformation of N-substituted aromatic amides 38 confines 3 or 4 to preferentially adopt all-cis conformations. A helical conformation is, therefore, strongly preferred in tetramer 4 and presumably in longer congeners, 39 while the four lowest-energy conformations of 3 or 3 − represent potential energy minima that directly lead to the corresponding macrocycles (Tables SI3−SI6; Figures SI22 and SI23).…”

Section: −15mentioning

confidence: 99%

One-Pot Synthesis and AFM Imaging of a Triangular Aramide Macrocycle

et al. 2014

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Macrocyclizations in exceptionally good yields were observed during the self-condensation of Nbenzylated phenyl p-aminobenzoates in the presence of LiHMDS to yield three-membered cyclic aramides that adopt a triangular shape. An ortho-alkyloxy side chain on the N-benzyl protecting group is necessary for the macrocyclization to occur. Linear polymers are formed exclusively in the absence of this Li-chelating group. A model that explains the lack of formation of other cyclic congeners and the demand for an N-(o-alkoxybenzyl) protecting group is provided on the basis of DFT calculations. High-resolution AFM imaging of the prepared molecular triangles on a calcite(10.4) surface shows individual molecules arranged in groups of four due to strong surface templating effects and hydrogen bonding between the molecular triangles.

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Section: −15mentioning

confidence: 99%

One-Pot Synthesis and AFM Imaging of a Triangular Aramide Macrocycle

et al. 2014

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“…N-methylbenzanilide and N,N¢-dimethyl-N,N¢-diphenyl-2,6-pyridine dicarboxamide. 6,7 In these compounds, both of the aromatic groups are placed at the cis-position when the amide C-N bond is considered as a double bond. In this case, the planes of these aromatic groups deviate from the plane of the amide group, and are oriented as face to face each other.…”

Section: X-ray Structure Analysis Onlinementioning

confidence: 99%

Crystal Structure of N-Methyl-N-phenyl-1,10-phenanthroline-2-carboxamide

Kobayashi

Suzuki

Shiwaku

et al. 2012

X-ray Structure Analysis Online

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The establishment of a disposal method of high-level radioactive waste, based on a simple and efficient separation strategy, is of increasing importance, and the development of an efficient separation ligand for minor actinides is strongly desired. Considering the transmutation of long-lived radionuclides, such as Am 3+ , into short-lived isotopes by neutron irradiation, in particular, the selective separation of minor actinides from lanthanides, which have a high neutron capture cross section, is a key technique. 1 To separate the trivalent actinides from lanthanides, a soft-donor ligand, such as an aza-aromatic nitrogen compound, is promising because these actinides show a slightly softer character than lanthanides. 1 However, most nitrogen ligands hardly coordinate to a metal ion in highly acidic media due to the protonation of nitrogen atoms, although the separation process is generally designed to perform in acidic media. In contrast, a newly synthesized aza-aromatic nitrogen based ligand, PTA, which was architected by the combination of both oxygen and nitrogen donors, effectively extracts and separates trivalent actinide from lanthanides by a liquid-liquid extraction method, even in a highly acidic condition. 2 N-Methyl-N-phenyl-1,10-phenanthroline-2-carboxamide, MePhPTA ( Fig. 1), is synthesized from 1,10-phenanthroline-2-carboxychloride and N-methylaniline. 1,10-phenanthroline-2-carboxychloride is also synthesized by a facile method. 2 Since the single crystal of MePhPTA, obtained through a purification process, was isolated, and the structure was determined by X-ray crystallography, the detailed structure and the features are discussed in this report.MePhPTA was synthesized by the reaction of 1,10-phenanthroline-2-carboxychloride (1.3 mmol) and N-methylaniline (13.4 mmol) in 1 mL of DMF at 70˚C for 16 h, and the resulting crude product was purified via column chromatography, eluting with an ethyl acetate and chloroform 1:1 mixture. The obtained MePhPTA was recrystallized from methanol to give a single crystal. This crystal was sufficiently stable for X-ray analysis. The structures were solved by a direct method, 3 and expanded using Fourier techniques. 4 The data were refined using a package program, CrystalStructure. 5 All of the non-hydrogen atoms were refined anisotropically. Although the positions of almost all hydrogen atoms were determined from a difference Fourier maps, all of the hydrogen atoms were refined using a riding model at the final stage of refinement. X-ray Structure Analysis OnlineCrystal Structure of N-Methyl-N-phenyl-1,10-phenanthroline-2-carboxamide Japan The single-crystal structure of N-methyl-N-phenyl-1,10-phenanthroline-2-carboxamide, MePhPTA, which is a promising ligand for the effective disposal of high-level radioactive waste, was determined by X-ray crystallography. The structure was solved by a direct method, and refined to R = 0.040. The oxygen atom of the amide group is oriented to the same side of the nitrogen atoms of the phenanthroline moiety. This conformation ...

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“…The N-substituted aromatic amide linkages generally prefer the cis conformation. 7 Hence, if a bulky substituent is introduced at the amide nitrogen atom of oligo(obenzamide), all of the amide linkage may adopt the cis conformation in order to avoid the repulsion between the N-substituent and the benzene unit connected to the carbonyl group at the same amide linkage. This leads to a helical structure in the oligo(o-benzamide).…”

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confidence: 99%