128676-97-1Relevant articles and documents
Directed ortho-Lithiation of Chloroquinolines. Application to Synthesis of 2,3-Disubstituted Quinolines
Marsais, F.,Godard, A.,Queguiner, G.
, p. 1589 - 1594 (2007/10/02)
2-, 3- and 4-Chloroguinolines were selectively lithiated at low temperature by lithium diisopropylamide at the more acidic C-3, C-4 and C-3 positions respectively.Reaction of 2-chloro-3-lithioquinoline with electrophiles led to various 2,3-disubstituted quinolines.The versatility of this functionalization methodology is enhanced by the C-2 halogen reactivity towards oxygen or nitrogen nucleophiles.So, a great variety of 2,3-disubstituted quinolines were synthesized, such as 2-chloro, 2-alkoxy, 2-aminoquinolines or 2-quinolones bearing an hydroxy, carbonyl (aldehyde, ketone or carboxylic acid), iodo, trimethylsilyl or boronic acid moiety at the C-3.Some of the resulting 2,3-disubstituted synthons were annelated to tetracyclic polyaromatics, which possess the xanthone or indole structure.This could be achieved via further functionalization of the quinoline ring either by SNAr2 or heteroaromatic cross-coupling reactions, after the first directed-lithiation step.
