Spirodienone derivatives of a spherand-type calixarene.
J Org Chem
; 66(9): 2891-9, 2001 May 04.
Article
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| MEDLINE
| ID: mdl-11325250
Oxidation of the spherand-type calixarene 4 with 1 or 2 equiv of phenyltrimethylammonium tribromide/base afforded mono- and bis(spirodienone) derivatives (8b and 9, respectively). The spirodienone groups are derived from the oxidation of two phenols connected by a common methylene group. NOESY data indicated that 9 possesses a "head to tail" arrangement of the spirodienone groups. Oxidation of 4 with 3 equiv of the oxidizing reagent afforded two tris(spirodienone) calixarene derivatives 11 and 10 with C(1) and C(3) symmetries, respectively. The same tris(spirodienone) products were obtained by oxidation of 9 with I(2)/aq KOH. Tris(spirodienone) 11 displayed NOE cross-peaks in the NOESY NMR spectrum consistent with a nonalternant disposition of carbonyl and ether groups. Upon heating 10 and 11 isomerize in the solid state and in solution. The major component in the equilibration mixtures is 11, indicating that this is the thermodynamically more stable tris(spirodienone) isomer.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
J Org Chem
Año:
2001
Tipo del documento:
Article
País de afiliación:
Israel
Pais de publicación:
Estados Unidos