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Synlett 2004(10): 1832-1834  
DOI: 10.1055/s-2004-829555
LETTER
© Georg Thieme Verlag Stuttgart · New York

Ytterbium Triflate Promoted Synthesis of Benzimidazole Derivatives

Massimo Curini*, Francesco Epifano, Francesca Montanari, Ornelio Rosati, Sara Taccone
Dipartimento di Chimica e Tecnologia del Farmaco - Sezione di Chimica Organica, Università di Perugia, Via del Liceo, 06123 Perugia, Italy
Fax: +39(075)5855116; e-Mail: curmax@unipg.it;
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Publication History

Received 24 March 2004
Publication Date:
15 July 2004 (online)

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Abstract

Differently substituted benzimidazoles have been synthesised in very good yields in solvent-free conditions from o-phenylenediamine and aldehydes in the presence of Yb(OTf)3 as catalyst. The method is applicable to aromatic, unsaturated and ­aliphatic aldehydes and to substituted o-phenylenediamines without significant differences.

Key words

aldehydes - benzimidazoles - catalysis - lanthanides

    References

  • 1 Velik J. Baliharova V. Fink-Gremmels J. Bull S. Lamka J. Skalova L. Res. Vet. Sci.  2004,  76:  95 
    CrossrefGoogle Scholar
  • 2 Yadagiri B. Lown JW. Synth. Commun.  1990,  20:  955 
    CrossrefGoogle Scholar
  • 3 Sun Q. Yan B. Bioorg. Med. Chem. Lett.  1998,  8:  361 
    CrossrefGoogle Scholar
  • 4 Preston PN. Benzimidazoles and Congeneric Tricyclic Compounds, In The Chemistry of Heterocyclic Compounds   Part 1 Vol. 40:  Weissberger A. Taylor EC. Wiley; New York: 1981.  p.6-60  
    Google Scholar
  • 5 Grimmett MR. Imidazoles and their Benzo Derivatives, In Comprehensive Heterocyclic Chemistry   Vol. 5:  Katritzky AR. Rees CW. Pergamon; Oxford: 1984.  p.457-487  
    Google Scholar
  • 6 Benincori T. Sannicolò F. J. Heterocycl. Chem.  1988,  25:  1029 
    Google Scholar
  • 7 Smith JG. Ho I. Tetrahedron Lett.  1971,  38:  3541 
    Google Scholar
  • 8 Weidenhagen R. Ber.  1936,  69:  2263 
    Google Scholar
  • 9 Jakobson P. Jannicke M. Meyer F. Ber.  1896,  29:  2682 
    Google Scholar
  • 10 Stevens FF. Bower JD. J. Chem. Soc.  1949,  2971 
    Google Scholar
  • 11 Kobayashi S. Sugiura M. Kitagawa H. Lam WWL. Chem. Rev.  2002,  6:  2227 
    Google Scholar
  • 12 Curini M. Epifano F. Marcotullio MC. Rosati O. Tetrahedron Lett.  2001,  42:  3193 
    CrossrefGoogle Scholar
  • 13 Typical Procedure. A mixture of o-phenylenediamine (1 mmol) and aldehyde (1.1 mmol) was well stirred with Yb(OTf)3 (0.05 mmol) at r.t. for 30 min. To this solution, CH2Cl2 (2 mL) was added to get Yb(OTf)3 crystallized; the catalyst was removed by filtration under reduced pressure and the residue was purified by SiO2 gel column chromatography using CH2Cl2-MeOH 99:1 as eluent. Compounds 1, 2, 3, 5, 6, 7, 8, 9 and 10 were identified by comparison with commercial samples. 2-(2,6-dimethylhept-5-enyl)-1 H -benzimidazole ( 4). White solid; mp 93-94 °C. 1H NMR (200 MHz, CDCl3): δ = 1.01 (d, 6 H, J = 6.6 Hz), 1.27-2.27 (m, 5 H), 2.67-3.10 (m, 2 H), 5.01-5.21 (m, 1 H), 6.75 (s, 1 H), 7.15-7.65 (m, 4 H). 13C NMR (50 MHz, CDCl3): δ = 18.9, 19.5, 25.5, 25.6, 32.9, 36.9, 37.0, 116.7, 120.2, 122.1, 124.2, 136.3, 142.6, 146.6, 154.2. GC-MS: m/z = 242 [M+]. Anal. Calcd for C16H22N2: C, 79.29; H, 9.15; N, 11.56. Found: C, 79.31; H, 9.16; N, 11.54
  • 15 Jerchel D. Fischer H. Kracht M. Ann. Chem.  1952,  575:  162 
    Google Scholar
14

The reaction to yield compound 1 has been repeated three times, through the catalyst washed with CH2Cl2 and dried for 2 h at 70 °C with the following yields: 94%, 91%, and 91%.