Hydrochloric Acid → 4-(1H-benzimidazol-2-yl)phenol

Participants

Reaction Steps

N,N'-Bis(p-propoxybenzoyl)-o-phenylenediamine (m.p. 196° C.) [prepared in 86% yield from p-propoxybenzoyl chloride and o-phenylenediamine was heated (200° C.) for four hours with concentrated hydrochloric acid. Mixture was cooled, neutralized with sodium bicarbonate and filtered. Recrystallization from ethanol gave 2-(p-hydroxyphenyl)benzimidazole (Yield 76%, m.p. 286°-288° C.). A well stirred mixture of 2-(p-hydroxyphenyl)benzimidazole (0.1 mole), iodoethane (0.1 mole) and sodium bicarbonate (0.12 mole) in 200 ml of acetone was refluxed overnight, filtered and the acetone removed on the steam bath. The isolated 2-(p-hydroxyphenyl)-1-methylbenzimidazole was reacted with 4-(2-bromoethoxy)-2-hydroxybenzophenone as in Example 1 to produce 4-{2-[4-(1-ethyl-2-benzimidazolyl)phenoxy]ethoxy}-2-hydroxybenzophenone.

Provenance & Evidence