182314-60-9Relevant academic research and scientific papers
Structures and stereodynamics of N-9-triptycylacetamide and its N-alkyl derivatives
Yamamoto, Gaku,Nakajo, Fusako,Tsubai, Natsuko,Murakami, Hiroaki,Mazaki, Yasuhiro
, p. 2315 - 2326 (2007/10/03)
X-Ray crystallographic and dynamic NMR spectroscopic studies were performed on N-9-triptycylacetamide (1), N-methyl-N-9-triptycylacetamide (2), N-ethyl-N-9-triptycylacetamide (3), and N-benzyl-N-9-triptycylacetamide (4). In the crystalline state, compounds 1, 2, and 4 exist solely as the Z-isomer for the amide bond, while equal amounts of the Z- and E-isomers exist in a single crystal of compound 3. The amide nitrogen atom in 2, 3, or 4 is significantly pyramidalized. In solution, 1 exists solely as the Z-isomer, while 2, 3, and 4 exist as an equilibrium mixture of the Z- and E-isomers. The isomer ratio is not correlated with the bulkiness of the N-alkyl group; the N-ethyl compound 3 seems to behave anomalously. The isomer ratio is significantly dependent on the solvent; the population of the Z-isomer in 2 or 3 or 4 increases with the solvent polarity. The Z?E interconversion takes place on the NMR time scale around ambient temperature, and the barrier is dependent on the solvent; hydroxylic solvents, methanol and ethanol, increase the barrier. The methylene protons in the ethyl or benzyl group in any isomer of 3 or 4 become diastereotopic at low temperatures suggesting that the nitrogen atom in either compound is pyramidal in solution. Stereomutation around the Tp-N bond is discussed in some detail.
Stereodynamics of N,N-dialkyl-9-triptycyclamines
Yamamoto, Gaku,Higuchi, Hiroyuki,Yonebayashi, Masami,Nabeta, Yuki,Ojima, Juro
, p. 12409 - 12420 (2007/10/03)
Stereodynamics of a series of N,N-dialkyl-9-triptycyclamines is studied by 1H and 13C dynamic NMR spectroscopy. The energy barriers to the observed internal motions are governed by the eclipsing interaction between an N-alkyl group a
Stereodynamics of N-Benzyl-N-methyl-9-aminotriptycene
Yamamoto, Gaku,Higuchi, Hiroyuki,Yonebayashi, Masami,Ojima, Juro
, p. 1911 - 1914 (2007/10/02)
Stereodynamics of N-benzyl-N-methyl-9-aminotriptycene is studied by 1H and 13C dynamic NMR spectroscopy.The energy barriers to internal motion are governed by the eclipsing interaction between an N-alkyl group and o-benzeno bridge of
