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Volumn 71, Issue 21, 2006, Pages 8166-8172

New practical synthesis of indazoles via condensation of o-fluorobenzaldehydes and their O-methyloximes with hydrazine

Author keywords

[No Author keywords available]

Indexed keywords

INDAZOLES; METHYLOXIMES; O-FLUOROBENZALDEHYDES;

EID: 33750011410     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo0613784     Document Type: Article
Times cited : (109)

References (40)
  • 4
    • 84943407995 scopus 로고
    • For reviews see; Katrizky, A. R., Rees, C. W., Eds.; Pergamon Press: New York
    • For reviews see: (a) Elguero, J. In Comprehensive Heterocyclic Chemistry; Katrizky, A. R., Rees, C. W., Eds.; Pergamon Press: New York, 1984; Vol. 5, p 167.
    • (1984) Comprehensive Heterocyclic Chemistry , vol.5 , pp. 167
    • Elguero, J.1
  • 9
    • 33749987196 scopus 로고    scopus 로고
    • U.S. Patent Application 2003070686, Aug 28, 2003
    • (b) Shoda, M.; Kuriyama, H. U.S. Patent Application 2003070686, Aug 28, 2003.
    • Shoda, M.1    Kuriyama, H.2
  • 12
    • 0001611428 scopus 로고
    • The diazotation method generally requires the isolation of a potentially explosive diazonium salt intermediate. The formation and cyclization of the diazonium salt proceed simultaneously under the reaction conditions only in the presence of additional highly electron-withdrawing groups (e.g., nitro): (a) Bartsch, R. A.; Tang, I.-W. J. Heterocycl. Chem. 1984, 21, 1063.
    • (1984) J. Heterocycl. Chem. , vol.21 , pp. 1063
    • Bartsch, R.A.1    Tang, I.-W.2
  • 14
    • 0000932162 scopus 로고
    • Even the most advanced modification of the Jacobsen reaction remains relatively impractical, as it requires the addition of 0.1 equiv of expensive and toxic crown ether catalyst, employs toxic chloroform as a preferred solvent, and adds a deprotection step to recover the indazole: (a) Beadle, J. R.; Korzeniowski, S. H.; Rosenberg, D. E.; Garcia-Slanga, B. J.; Gokel, G. W. J. Org. Chem. 1984, 49, 1594-1603.
    • (1984) J. Org. Chem. , vol.49 , pp. 1594-1603
    • Beadle, J.R.1    Korzeniowski, S.H.2    Rosenberg, D.E.3    Garcia-Slanga, B.J.4    Gokel, G.W.5
  • 16
    • 0842326654 scopus 로고    scopus 로고
    • Bromoindazole 3 was obtained as one of the products resulting from the condensation of bromobenzyne with (trimethylsilyl)diazomethane: Shoji, Y.; Hari, Y.; Aoyama, T. Tetrahedron Lett. 2004, 45, 1769-1771.
    • (2004) Tetrahedron Lett. , vol.45 , pp. 1769-1771
    • Shoji, Y.1    Hari, Y.2    Aoyama, T.3
  • 27
    • 33750022802 scopus 로고    scopus 로고
    • note
    • It is possible that intramolecular cyclization of hydrazones with the formation of indazoles still could be accomplished at higher temperatures. In the related study of the intramolecular cyclizations of 2-mesyloxyacetophenones hydrazones (ref 18, eq 4), the indazole formation was observed at temperatures above 130 °C. However, a DSC scan of hydrazone 13 indicated that it underwent highly exothermic decomposition at 140-150 °C, prompting us to set 110 °C as the upper limit for all our experiments.
  • 31
    • 33750001926 scopus 로고    scopus 로고
    • note
    • We did not attempt to identify the structures of minor side products formed in these reactions in less than 5% peak area by HPLC methodology.
  • 34
    • 33749994644 scopus 로고    scopus 로고
    • note
    • 19F coupling.
  • 35
    • 37049044543 scopus 로고
    • For examples of halogen displacement with hydrazine in substituted benzonitrile see: (a) Parnell J. Chem. Soc. 1959, 2363.
    • (1959) J. Chem. Soc. , pp. 2363
    • Parnell1
  • 37
    • 33750024430 scopus 로고    scopus 로고
    • note
    • Alternatively, nitrile formation could occur after fluoride substitution with hydrazine. This, however, seems less likely, as a highly electron-donating hydrazide will deactivate the methyloxime group for elimination.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.