Synthesis of N-hydroxyenamide, a potential precursor of chartelline

Tetrahedron Letters

Volumn 49, Issue 4, 2008, Pages 594-597

  Kajii, Shigeo ^a   Nishikawa, Toshio ^a   Isobe, Minoru ^a  

^a NAGOYA UNIVERSITY   (Japan)

Author keywords

Chartelline; Imidazole; N Hydroxyenamide; Oxime

Indexed keywords

ALKALOID DERIVATIVE; CHARTELLINE DERIVATIVE; N ALLYLOXYENAMIDE; N HYDROXYENAMIDE; OXIME DERIVATIVE; UNCLASSIFIED DRUG;

ACYLATION; ARTICLE; DRUG SYNTHESIS;

EID: 37549038286     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tetlet.2007.11.155     Document Type: Article

References (25)

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11. To the best of our knowledge, there is only one report regarding the synthesis of cycloalkoxy enamide, see:. Lee V.J., and Woodward R.B. J. Org. Chem. 44 (1979) 2487-2491
12. Enamide has been synthesized by N-acylation of oxime in the presence of iron as a reducing agent, see:. Barton D.H.R., and Zard S.Z. J. Chem. Soc., Perkin Trans. 1 (1985) 2191-2192
13. Laso N.M., Quiclet-Sire B., and Zard S.Z. Tetrahedron Lett. 37 (1996) 1605-1608
14. We attempted copper-catalyzed coupling of hydroxamate with vinylhalide under the conditions developed for enamide synthesis. For example, see:. Jiang L., Job G.E., Klapars A., and Buchwald S.L.. Org. Lett. 5 (2003) 3667-3669
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16. All reactions in Tables 1 and 2 gave E isomers exclusively. The geometry was determined by the coupling constant, J = 14-15 Hz.
17. O-Substituted hydroxylamines were prepared from N-hydroxylphthalimide by alkylation or Mitsunobu reaction with the corresponding alcohol. See:. Ramsay S.L., Freeman C., Grace P.B., Redmond J.W., and MacLeod J.K. Carbohydr. Res. 333 (2001) 59-71
18. 4: C, 72.62; H, 6.77; N, 6.27. Found: C, 72.63; H, 6.80; N, 6.23.
19. 3N or pyridine was added for the same purpose, the yield of the product decreased.
20. Oximes 8a-c were prepared from the corresponding aldehydes. The synthesis of these aldehydes will be reported elsewhere.
21. Dicationic intermediate referred to in the text.{A figure is presented}
22. 4 402.0851, found 402.0889.
23. The structure of the less polar product is assumed to be the corresponding enamide, which has an N-phenylacetyl group attached to the imidazole ring.
24. 6 631.1954, found 631.1928.
25. Before the acid treatment, the product was an allyloxyenamide containing N-indoleacetyl imidazole, which could be isolated by silica gel TLC.