New efficient route for solid-phase synthesis of benzimidazole derivatives.
A simple and efficient method for the solid-phase synthesis of benzimidazole libraries is described. Monoalkylation of various o-phenylenediamines on resin-bound bromoacetamide proceeded smoothly to give the monoalkyl resin-bound o-phenylenediamines in high yields. Subsequent cyclization of the diamines with various aldehydes afforded solid-supported benzimidazoles. Cleavage from the resin gave benzimidazoles in good yields. The present method enabled the introduction of the diversity on the benzene ring of imidazoles. Azabenzimidazoles, such as 4-azabenzimidazoles, 5-azabenzimidazoles, and purines, were also synthesized in good yields with high purities by the same procedure.
Akamatsu
Hisashi
H
Department of Chemistry, Graduate School of Science, Osaka University, Machikaneyama-cho 1-1, Toyonaka, Osaka 560-0043, Japan.
Fukase
Koichi
K
Kusumoto
Shoichi
S