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Volumn 10, Issue 21, 2008, Pages 4935-4938

Unexpected catalysis: Aprotic pyridinium ions as active and recyclable Brønsted acid catalysts in protic media

Author keywords

[No Author keywords available]

Indexed keywords

ACID; BUFFER; ION; PYRIDINIUM DERIVATIVE;

EID: 58149152878     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol802008m     Document Type: Article
Times cited : (53)

References (33)
  • 4
    • 27644465867 scopus 로고    scopus 로고
    • Catalysts/ionic liquids which incorporate N-alkylpyridinium ions for which no specific catalytic role has been identified for the pyridinium ring other than as a polar/or electron-deficient group have been reported; for representative recent examples, see: (a) Maki, T.; Ishihara, K.; Yamamoto, H. Org. Lett. 2005, 7, 5043.
    • Catalysts/ionic liquids which incorporate N-alkylpyridinium ions for which no specific catalytic role has been identified for the pyridinium ring other than as a polar/or electron-deficient group have been reported; for representative recent examples, see: (a) Maki, T.; Ishihara, K.; Yamamoto, H. Org. Lett. 2005, 7, 5043.
  • 9
    • 49149101685 scopus 로고    scopus 로고
    • Kull, T.; Peters, R. Angew. Chem., Int. Ed. 2008, 47, 5461.
    • (f) Kull, T.; Peters, R. Angew. Chem., Int. Ed. 2008, 47, 5461.
  • 13
    • 38949186008 scopus 로고    scopus 로고
    • Pyridinium ionic liquid solvents have also recently been shown to facilitate photoinduced electron-transfer processes: Vieira, R. C, Falvey, D. E J. Am. Chem. Soc. 2008, 130, 1552
    • Pyridinium ionic liquid solvents have also recently been shown to facilitate photoinduced electron-transfer processes: Vieira, R. C.; Falvey, D. E J. Am. Chem. Soc. 2008, 130, 1552.
  • 15
    • 60949085043 scopus 로고    scopus 로고
    • It should be noted that this is not compatible with the more usual stablization of the oxyanion by hydrogen bonding in the oxyanion hole postulated as being key in several serine/cysteine proteases
    • It should be noted that this is not compatible with the more usual stablization of the oxyanion by hydrogen bonding in the "oxyanion hole" postulated as being key in several serine/cysteine proteases.
  • 16
    • 39649096743 scopus 로고    scopus 로고
    • The Kamlet, Taft parameters for several ionic liquids containing a pyridinium cation have recently been determined; see: Lee, J.-M, Ruckes, S, Prausnitz, J. M. J. Phys. Chem. B 2008, 112, 1473-1476
    • The Kamlet - Taft parameters for several ionic liquids containing a pyridinium cation have recently been determined; see: Lee, J.-M.; Ruckes, S.; Prausnitz, J. M. J. Phys. Chem. B 2008, 112, 1473-1476.
  • 17
    • 60949096757 scopus 로고    scopus 로고
    • A catalysis mode involving hydrogen bonding mediated by the primary amide moiety was considered unlikely in methanolic solvent
    • A catalysis mode involving hydrogen bonding mediated by the primary amide moiety was considered unlikely in methanolic solvent.
  • 20
    • 60949105130 scopus 로고    scopus 로고
    • After proton transfer from oxygen to nitrogen
    • After proton transfer from oxygen to nitrogen.
  • 24
    • 60949085833 scopus 로고    scopus 로고
    • Under alkaline conditions, it is known that N-alkylpyridinium ions derived from nicotinamide underwent addition of hydroxide at C-4: Dittmer, D. C.; Koyler, J. M. J. Org. Chem. 1963, 28, 2228.
    • Under alkaline conditions, it is known that N-alkylpyridinium ions derived from nicotinamide underwent addition of hydroxide at C-4: Dittmer, D. C.; Koyler, J. M. J. Org. Chem. 1963, 28, 2228.
  • 25
    • 0021513937 scopus 로고    scopus 로고
    • under basic conditions, thiolates and enolates have been shown to reversibly add to pyridinium ions. For a review and a recent (noncatalytic) application of this reaction class, respectively, see: (a) Kellogg, R. M
    • Similarly, under basic conditions, thiolates and enolates have been shown to reversibly add to pyridinium ions. For a review and a recent (noncatalytic) application of this reaction class, respectively, see: (a) Kellogg, R. M. Angew. Chem., Int. Ed. 1984, 23, 782.
    • (1984) Angew. Chem., Int. Ed , vol.23 , pp. 782
    • Similarly1
  • 27
    • 60949091378 scopus 로고    scopus 로고
    • Significant decomposition of the nitrile 16 was observed.
    • Significant decomposition of the nitrile 16 was observed.
  • 29
    • 60949108303 scopus 로고    scopus 로고
    • a would suggest (0.1 mol %, 89% yield).
    • a would suggest (0.1 mol %, 89% yield).
  • 30
    • 60949092284 scopus 로고    scopus 로고
    • In the corresponding control reactions in the absence of 22 conversion had not reached 5% after this reaction time in the reactions involving 27 and 28
    • In the corresponding control reactions in the absence of 22 conversion had not reached 5% after this reaction time in the reactions involving 27 and 28.
  • 31
    • 60949114421 scopus 로고    scopus 로고
    • While no new species were observed in the 1H NMR spectrum of 22 when recorded in CD3OD (as opposed to CDCl3, its UV spectrum (9.8 × 10-5 M) is significantly different in MeOH than that recorded in H2O and in a 9/1 H2O/MeOH mixture. Strong absorption bands not observed in the aqueous spectra are present with maxima at 250, 269, and 352 nm. See the Supporting Information for details and spectra
    • 2O/MeOH mixture. Strong absorption bands not observed in the aqueous spectra are present with maxima at 250, 269, and 352 nm. See the Supporting Information for details and spectra.
  • 32
    • 0021513937 scopus 로고    scopus 로고
    • + at C-4 before attacking the aldehyde substrate to form the hemithioacetal. While this idea has not gained widespread currency, it has begun to be re-examined recently. For representative references see: (a) Kellogg, R. M. Angew. Chem., Int. Ed. 1984, 23, 782.
    • + at C-4 before attacking the aldehyde substrate to form the hemithioacetal. While this idea has not gained widespread currency, it has begun to be re-examined recently. For representative references see: (a) Kellogg, R. M. Angew. Chem., Int. Ed. 1984, 23, 782.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.