Synthesis, characterization, and catalytic reactivity of a highly basic macrotricyclic aminopyridine.
The synthesis methods, physicochemical and structural characteristics, and catalytic reactivity of new macrocyclic proton chelators, N,N',N''-tris(p-tolyl)azacalix[3](2,6)(4-pyrrolidinopyridine) and N,N',N''-tris(p-tolyl)azacalix[3](2,6)(4-piperidinopyridine), are studied. The introduction of pyrrolidino and piperidino groups into the pyridine unit enables the enhancement of the synergistic proton affinity of the cavity of the macrotricycle giving a high basicity (pK(BH+) = 28.1 and 27.1 in CD(3)CN), resulting in a catalytic activity for the Michael addition of nitromethane with α,β-unsaturated carbonyl compounds.
Tsukuba Research Center for Interdisciplinary Materials Science (TIMS), Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8573, Japan.
Natsuko
N
Uchida
Ayako
A
Taketoshi
Junpei
J
Kuwabara
Toshihide
T
Yamamoto
Yoshiaki
Y
Inoue
Yu
Y
Watanabe
Takaki
T
Kanbara