TITLE:
Palladium-Catalyzed Sonogashira Coupling Reaction of 2-Amino-3-Bromopyridines with Terminal Alkynes
AUTHORS:
Qing Zhu, Lichun Liao, Guo Cheng, Wen Yang, Yingying Deng, Dingqiao Yang
KEYWORDS:
Palladium Catalyst, 2-Amino-3-Bromopyridines, Terminal Alkynes, Sonogashira Coupling Reaction
JOURNAL NAME:
Modern Research in Catalysis,
Vol.6 No.3,
July
13,
2017
ABSTRACT: Palladium-catalyzed the Sonogashira coupling reaction of
3-halogen-2-aminopyridines 1 with terminal alkynes 2 afforded
the corresponding 21 target products 3a-3u in the presence of
palladium catalyst. The structure of target products 3a-3u was
confirmed and characterized by 1H NMR, 13C NMR,
and HRMS. The influences of different kinds of catalyst loading, bases, substrates
and temperature were also investigated. Under the optimized conditions,
including 2.5 mol% Pd(CF3COO)2, 5 mol% PPh3 and 5 mol%
CuI as additive, 1 mL Et3N, substrate 1 with terminal
alkynes 2 for the cross-coupling reactions at 100°C for 3 h in DMF afforded the
corresponding products of 2-amino-3-alkynylpyridines 3 in moderate to excellent yields (72%-96%). The present methodology
has provided an effective synthetic method including operational convenience,
high efficiency and wide-application.