Tin-free radical cyclizations for the synthesis of 7-azaoxindoles, 7-azaindolines, tetrahydro[1,8]naphthyridines, and tetrahydro-5H-pyrido[2,3-b]azepin-8-ones.
[reaction: see text] Compounds containing a pyridine nucleus fused to a saturated nitrogen-containing ring, including 7-azaoxindoles, 7-azaindolines, tetrahydro[1,8]naphthyridines, and tetrahydro-5H-pyrido[2,3-b]azepin-8-ones, were prepared in good yield starting from various 2,6-dichloropyridines. The method hinges on a free-radical xanthate-mediated cyclization or intermolecular addition/cyclization sequence for the construction of the new fused rings.
AVENTIS Pharma, 94 400 Vitry sur Seine, France.
Eric
E
Bacqué
Myriem
M
El Qacemi
Samir Z
SZ
Zard
D001381:Azepines / Q000138:chemical synthesis*; D003500:Cyclization; D005609:Free Radicals / Q000737:chemistry; D007211:Indoles / Q000138:chemical synthesis*; D009287:Naphthyridines / Q000138:chemical synthesis*; D014001:Tin / Q000737:chemistry*
D001381:Azepines; D005609:Free Radicals; D007211:Indoles; D009287:Naphthyridines; D014001:Tin