Aryne [3 + 2] cycloaddition with N-sulfonylpyridinium imides and in situ generated N-sulfonylisoquinolinium imides: a potential route to pyrido[1,2-b]indazoles and indazolo[3,2-a]isoquinolines.
Org Biomol Chem
; 10(9): 1922-30, 2012 Mar 07.
Article
in En
| MEDLINE
| ID: mdl-22278679
ABSTRACT
The aryne [3 + 2] cycloaddition process with pyridinium imides breaks the aromaticity of the pyridine ring. By equipping the imide nitrogen with a sulfonyl group, the intermediate readily eliminates a sulfinate anion to restore the aromaticity, leading to the formation of pyrido[1,2-b]indazoles. The scope and limitation of this reaction are discussed. As an extension of this chemistry, N-tosylisoquinolinium imides, generated in situ from N'-(2-alkynylbenzylidene)-tosylhydrazides via an AgOTf-catalyzed 6-endo-dig electrophilic cyclization, readily undergo aryne [3 + 2] cycloaddition to afford indazolo[3,2-a]-isoquinolines in the same pot, offering a highly efficient route to these potential anticancer agents.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Phenazopyridine
/
Sulfur Compounds
/
Imides
/
Indazoles
/
Isoquinolines
Language:
En
Journal:
Org Biomol Chem
Journal subject:
BIOQUIMICA
/
QUIMICA
Year:
2012
Document type:
Article