Synthesis of a series of novel fused tetracyclic mono- and diazaindolo[2,1-c][1,4]benzoxazine heterocyclic compounds 3a–o has been achieved in a two-step one-pot reaction set up starting from commercially available or easily accessible inputs. For example, reaction of di-lithiated (N-Boc)-2-amino-3-methylpyridine Li2–2a with Weinreb amide of 2-(2,4-difluorophenoxy)-2,2-dimethylacetic acid 1a, followed by TFA treatment furnished the tetracyclic compound 3a, which is essentially a fusion of 7-azaindole and 3,4-dihydro[1,4]benzoxazine, in 70% isolated yield. A competitive elimination by-product 4a was also observed (24% isolated yield) in this case. Based on our initial results, a structural basis and molecular mechanism have been suggested to explain these two parallel reactions. Consequently, with appropriate structural tuning of 1, formation of the individual products can be controlled.
|Titolo:||Synthesis of a novel tetracyclic azaindolo[2,1-c][1,4]benzoxazine ring system|
|Parole Chiave:||(N-Boc)-2-amino-3-methylpyridine; 2-(2,4-Difluorophenoxy)-2,2-dimethylacetic acid; Azaindolo[2,1-c][1,4]benzoxazine; Diazaindolo[2,1-c][1,4]benzoxazine; Weinreb amide|
|Settore Scientifico Disciplinare:||Settore CHIM/06 - Chimica Organica|
|Data di pubblicazione:||20-apr-2011|
|Digital Object Identifier (DOI):||10.1016/j.tetlet.2011.02.020|
|Appare nelle tipologie:||01 - Articolo su periodico|