| 摘要 |
Prodn. of 5-chloro-2-pyridinecarboxamide derivs. of formula (I) is effected by: (a) reacting 2,5-dichloropyridine (II) with an alkyne of formula RICCH (III) in the presence of a Pd phosphine complex catalyst (IV), oxidising the resulting 2-alkynyl-5-chloropyridine (V) to form 5-chloro-2-pyridinecarboxylic acid (VI), and reacting (VI) or a reactive deriv. of (VI) with an amine of formula RCH2CH2NH2 (VII); or (b) reacting (II) with CO and (VII) in the presence of (IV); or (c) reacting (II) with CO and opt. an aq. lower alkanol in the presence of (IV) to form (VI) or a lower alkyl ester of (VI), and reacting this with (VII). In formulae, R1 = H, lower alkyl, SiMe3 or CR2R3OH; R2 and R3 = H or lower alkyl, or CR2R3 = cyclopentylene or cyclohexylene; R = NH2 or a gp. convertible to NH2. Pref. (IV) is (Ph3)2PdCl2 or is formed in situ from PdCl2 or Pd(OAc)2 and 1,3-bis(diphenylphosphino)propane (BDP). |
