Stereochemistry in trivalent nitrogen compounds. XXVIII. Conformational analysis and torsional barriers of imides and triamides

Noe, Eric A.; Raban, Morton

doi:10.1021/ja00853a027

Cited by 60 publications

(23 citation statements)

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“…The determined values for the amide bond rotation barriers are in agreement to those reported for other benzamides, which are in the range of 57-73 kJ mol À1 . [46][47][48] The observed solvent effect on the rotational barriers is also in accord to literature reports and can be explained by the fact that more polar solvent molecules can better stabilize the zwitterionic canonical form of the amide bond ( Fig. 3 top right).…”

Section: Mono-substituted Piperazinessupporting

confidence: 89%

NMR-based investigations of acyl-functionalized piperazines concerning their conformational behavior in solution

et al. 2018

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Section: Mono-substituted Piperazinessupporting

confidence: 89%

NMR-based investigations of acyl-functionalized piperazines concerning their conformational behavior in solution

et al. 2018

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“…[3] In contrast to the experimentally unknown acid of dca, HN(CN) 2 , the free acid of dfa, HNA C H T U N G T R E N N U N G (CHO) 2 , has been synthesized and identified on the basis of IR, microwave, and 1 H NMR data. [3][4][5] As expected for a pseudohalide, the silver salt is insoluble in water, [6] and it was possible to isolate the very labile halogen-pseudohalogen compound bromodiformylamide, BrNA C H T U N G T R E N N U N G (CHO) 2 , in small yields. [3] Tetraformylhydrazine represents, according to the pseudohalogen concept, a bimolecular pseudohalogen which is known and fully characterized.…”

Section: Introductionmentioning

confidence: 83%

“…[4] Two years later, Noe and Raban reported (E,E)-diformamide on the basis of 1 H NMR data as the most stable conformer. [5] To shed some light on this structural problem, a single crystal X-ray study was carried out.…”

Section: Introductionmentioning

confidence: 99%

Salts and Ionic Liquids of Resonance Stabilized Amides

Brand

Martens

Mayer

et al. 2009

Chemistry An Asian Journal

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The synthesis, structure, and bonding of alkali salts of resonance stabilized amides, such as diformylamide (dfa), formylcyanoamide (fca), nitrocyanoamide (nca), and for comparision, the well-known dicyanoamide (dca), are discussed on the basis of experimental and theoretical data. The first structural reports of K(18-crown-6)+dfa-, K(18-crown-6)+fca-, Na+nca-, and Li(TMEDA)+dca- are presented. Examination of the X-ray data reveals almost planar anions with strong cation-anion interactions resulting in network-like structures in the solid state. For comparison, the X-ray structures of covalently bound phenyldicyanoamide and diformamide are also discussed. The thermal behavior of the alkali salts of these amides is studied by thermoanalytical experiments. Moreover, several novel ionic liquids based on resonance stabilized amides have been prepared and were fully characterized, namely the dfa, fca, and nca salts of EMIM (1-ethyl-3-methyl-imidazolium), BMIM (1-butyl-3-methyl-imidazolium), and HMIM (1-hexyl-3-methyl-imidazolium). Most of them are liquid at room temperature, except BMIM+fca- that melts at 32 degrees C. These ionic liquids are neither heat nor shock sensitive, are thermally stable up to over 200 degrees C, and can be prepared easily in large quantities.

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“…To this end, N-acetylpropanamide was synthesized and photolysed in CH3OD; incorporation of one deuterium atom into the methyl propanoate photoproduct indicates that -y-hydrogen abstraction is occurring in this case (Mazzocchi et al, 1980). This is in accord with the preferred (E,Z) conformation for such imides in solution (Noe & Raban, 1975), which has the abstracting O and abstracted H in close proximity. (3) 1.399 (7) 1.397 (3) NI---CI4 1.431 (2) 1.417 (3) 1.418 (7) 1.433 (3) CI--N1---C8 120.3 (2) 121.1 (2) 117.5 (4) 118.2 (2) CI--NI---C14 123.0 (2) 120.2 (2) 122.4 (4) 122.5 (2) C8--N1---C14 115.8 (2) 118.1 (2) 119.1 (5) 118.2 (2) SI:=C1--NI---CI4 -158.3 (2) -145.7 (2) -146.8 (4) -149.2 (2) CI--N 1---CI4---~OI 29.9 (3) 23.8 (4) 13.4 (8) 0.4 (4)…”

Section: C3mentioning

confidence: 96%