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Volumn 73, Issue 22, 2008, Pages 9102-9108

Nonplanar structures of thioamides derived from 7-azabicyclo[2.2.1]heptane. Electronically tunable planarity of thioamides

Author keywords

[No Author keywords available]

Indexed keywords

NUCLEAR MAGNETIC RESONANCE; NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; SOLID SOLUTIONS;

EID: 56449107511     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo801996b     Document Type: Article
Times cited : (31)

References (27)
  • 5
    • 0029945602 scopus 로고    scopus 로고
    • For a counter-example to the resonance effect, see
    • For a counter-example to the resonance effect, see: Laidig, K. E.; Cameron, L. M. J. Am. Chem. Soc. 1996, 118, 1737-1742.
    • (1996) J. Am. Chem. Soc , vol.118 , pp. 1737-1742
    • Laidig, K.E.1    Cameron, L.M.2
  • 14
    • 56449098611 scopus 로고    scopus 로고
    • This is due to high-density packing of 1f with a Z-value of 8 and an aromatic stacking distance of 3.4 Å
    • This is due to high-density packing of 1f with a Z-value of 8 and an aromatic stacking distance of 3.4 Å.
  • 19
    • 56449130405 scopus 로고    scopus 로고
    • Regression coefficients (r) and regression slopes (ρ, of corresponding amides are as follows see ref 11, r, 0.98, ρ, 0.61 for 4 and r, 0.99 and ρ, 0.82 for 5
    • + = 0.82 for 5.
  • 21
    • 0035820034 scopus 로고    scopus 로고
    • The fact that the negative entropic contribution is larger in more polar nitrobenzene than in o-dichlorobenzene can be partially explained in terms of enhanced solvation of thioamides, especially of the bicyclic thioamides, upon rotation. As for solvent effects on thioamide rotation, see: Wiberg, K. B.; Rush, D. J. J. Am. Chem. Soc. 2001, 123, 2038-2046.
    • The fact that the negative entropic contribution is larger in more polar nitrobenzene than in o-dichlorobenzene can be partially explained in terms of enhanced solvation of thioamides, especially of the bicyclic thioamides, upon rotation. As for solvent effects on thioamide rotation, see: Wiberg, K. B.; Rush, D. J. J. Am. Chem. Soc. 2001, 123, 2038-2046.
  • 22
    • 84989614083 scopus 로고    scopus 로고
    • This observation is consistent with a previous study of the corresponding amides, i.e, monocyclic and acyclic amides, a Pinto, B. M, Grindley, T. B, Szarek, W. A. Magn. Reson. Chem. 1986, 24, 323-331
    • This observation is consistent with a previous study of the corresponding amides, i.e., monocyclic and acyclic amides, (a) Pinto, B. M.; Grindley, T. B.; Szarek, W. A. Magn. Reson. Chem. 1986, 24, 323-331.
  • 24
    • 33748960439 scopus 로고    scopus 로고
    • ΔH is equal to the difference of potential energy E plus RT, zero-point energy, and the thermal corrections. Thus, it is well accepted that ΔH‡ is approximately equal to ΔE (which is obtained by calculation) along the reaction coordinate. See: Houk, K. N, Li, Y, Evanseck, J. D. Angew. Chem, Int. Ed. Engl. 1992, 31, 682-708
    • ‡ is approximately equal to ΔE (which is obtained by calculation) along the reaction coordinate. See: Houk, K. N.; Li, Y.; Evanseck, J. D. Angew. Chem., Int. Ed. Engl. 1992, 31, 682-708.
  • 25
    • 56449104322 scopus 로고    scopus 로고
    • The planarity (in terms of α value) of the calculated structures of the thioamides was also dependent on the electron-withdrawing nature of the aromatic substituents. In the case of the bicyclic thioamides 1: 1h (R, NO2) 160.7° > 1g (R, CN) 160.1° > 1f (R, COOMe) 159.8° > 1e (R, Cl) 158.8° > 1a (R, H) ≈ 1d (R, CH3) 158.1° > 1c (R, OMe) 157.2° > 1b (R, N(CH3)2) 156.0°. In the case of the monocyclic 2: 2h (R, NO2) 172.5° > 2g (R, CN) ≈ 2f (R, COOMe) 172.0° > 2e (R, Cl) 171.3° ≈ 2a (R, H) 171.5° ≈ 2d (R, CH 3) 171.2° > 2c (R, OMe) 170.3° > 2b (R, N(CH3)2) 169.5°. The dependency of 2 was smaller than that of 1, which was consistent with the trend found in the cr
    • 2) 169.5°. The dependency of 2 was smaller than that of 1, which was consistent with the trend found in the crystal structures. See Table S1 in Supporting Information.
  • 26
    • 56449084034 scopus 로고    scopus 로고
    • We thank an anonymous reviewer for valuable comment about the contribution of resonance structure D
    • We thank an anonymous reviewer for valuable comment about the contribution of resonance structure D.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.