Synthesis and reactivity of pyrrolo[3,2-e]indole: Removal of a N-BOM group from an unactivated indole

Article abstract of DOI:10.1016/S0040-4039(97)00198-6

A practical synthesis of pyrrolo[3,2-e]indole (1) is described. Different hydrogenation conditions of the indol-4-ylacetonitrile (3) afforded either 1-BOM-pyrrolo[3,2-e]indole (4, 42% from 5-nitroindole) or 1-hydroxymethylpyrrolo[3,2-e]indole (5, 46% from 5-nitroindole). Removal of the benzyl group was found to be problematic, but could be accomplished in moderate yield. Treatment of the resulting 1-hydroxymethylpyrrolo[3,2-e]indole (5) with NaOH in THF afforded 1 (94% from 5). Limited studies on the chemistry of 1 are also presented.