Selective synthesis of novel cyclic phenylazomethine trimers
J Org Chem
; 65(18): 5680-4, 2000 Sep 08.
Article
en En
| MEDLINE
| ID: mdl-10970311
ABSTRACT
Novel cyclic phenylazomethine trimers (CPAs) were synthesized in a one-step dehydration of the 4-aminobenzophenone derivatives in the presence of TiCl(4) or p-toluenesulfonic acid (PTS). The CPAs were isolated in over 90% yield under nondilute conditions. When using TiCl(4) as the dehydration agent, the induction of bulky substituents at the alpha-position of the substrate enhanced the yields of the CPAs. On the other hand, PTS served as an effective catalyst for the synthesis of the phenyl-substituted CPA. This different reactivity between TiCl(4) and PTS depends on the dehydration mechanism being dominated by a kinetic process or thermodynamic one. The obtained CPAs were confirmed by NMR, UV-vis spectra, and MM2 calculation to have only a Z conformation and a nonconjugated structure compared to the linear oligophenylazomethines (OPAs) and the aniline-capped OPAs (OPA's).
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
J Org Chem
Año:
2000
Tipo del documento:
Article
País de afiliación:
Japón