1,4- and 1,3-dipolar reactivity of alpha-alkoxycarbonylcycloimmonium N-aminides with dipolarophiles: synthesis of new imidazo[2,1-f][1,2,4]triazinium inner salts.
J Org Chem
; 66(25): 8528-36, 2001 Dec 14.
Article
em En
| MEDLINE
| ID: mdl-11735534
ABSTRACT
2-Alkoxycarbonylazolium N-aminides are interesting species, as they have the potential to act as efficient 1,4-dipole equivalents when they react with heterocumulenes, such as iso(thio)cyanates and carbodiimides. These reactions give heterobetaines containing the imidazo[2,1-f][1,2,4]triazinium system, in a formal [4 + 2] cyclocondensation process. These N-aminides, however, can also behave as 1,3-dipoles when they react with isocyanates to afford a cycloadduct that, depending on the position of alkoxycarbonyl group, can undergo a reversion process or a ring expansion to the more stable heterobetaine system.
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01-internacional
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MEDLINE
Idioma:
En
Revista:
J Org Chem
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Espanha