UNUSUAL TRANSFORMATION OF 4-METHYLDIHYDROFURO[2,3-H]COUMARIN-9-ONE OXIME IN PRESENCE OF BECKMANN REARRANGEMENT CATALYSTS

Authors
KRAVTCHENKO DV CHIBISOVA TA TRAVEN VF
Citation
Dv. Kravtchenko et al., UNUSUAL TRANSFORMATION OF 4-METHYLDIHYDROFURO[2,3-H]COUMARIN-9-ONE OXIME IN PRESENCE OF BECKMANN REARRANGEMENT CATALYSTS, Heterocyclic communications, 3(4), 1997, pp. 331-338
Citations number
12
Categorie Soggetti
Chemistry Inorganic & Nuclear
Journal title
Heterocyclic communications → ACNP
ISSN journal
07930283
Volume
3
Issue
4
Year of publication
1997
Pages
331 - 338
Database
ISI
SICI code
0793-0283(1997)3:4<331:UTO4O>2.0.ZU;2-0
Abstract
The rearrangement of 4-methyIdihydrofuro[2,3-h]coumarin-9-one oxime in presence of Beckmann catalyst (mixture of glacial acetic acid with HC l or HBr) or POCl3 provides corresponding 8-halogeno-4-methyldihydrofu ro[2,3-h]coumarin- 9-ones formation. alpha-Halogenation of condensed f uranone ring seems to be due to imin-amin tautomerism of the oxime. 8- Halogeno-4-methyldihydrofuro[2,3-h] coumarin-9-ones have been transfor med to 9-acetoxy-8-halogeno-4-methylangelicins (due to their ketoenol tautomerism) and to 8-substituted derivatives (due to their reactivity with nucleophiles).