Multistep parallel synthesis of substituted 5-aminobenzimidazoles in solution phase.
An efficient solution-phase parallel synthesis of multisubstituted 5-aminobenzimidazoles is described. The two fluorine atoms of 1,5-difluoro-2,4-dinitrobenzene (DFDNB) are sequentially and quantitatively replaced by nucleophiles. Simultaneous reduction of aromatic m-dinitro groups by Pd-C/HCOONH(4) results in 2,4,5-benzenetriamines, which are continuously condensed with aldehydes to successfully construct the benzimidazole ring without additional oxidants. The free aromatic amino group is further modified by anhydrides, isocyanates, isothiocyanates, and sulfonyl chlorides. All the reactions involved here are highly effective in giving the desired products at room temperature. Four diversity points are introduced in the final products.
Li
Li
L
Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, 1 Xian Nong Tan Street, Beijing 100050, P. R. China.
Liu
Gang
G
Wang
Zhanguo
Z
Yuan
Yunyun
Y
Zhang
Chunxu
C
Tian
Hongyu
H
Wu
Xianghong
X
Zhang
Jing
J