Nitro derivatives of 1,3-dihydrobenzimidazol-2-one: II. Rearrangement of N-nitrobenzimidazol-2-ones

Abstract

N-Nitrobenzimidazol-2-ones readily undergo rearrangement to C-nitro derivatives on heating in various solvents (ethyl acetate, butyl acetate, acetonitrile, acetone, dioxane, o-dichlorobenzene, anisole, acetic acid). This rearrangement was used to develop a procedure for the synthesis of 4,5,6,7-tetranitro-1,3-dihydrobenzimidazol-2-one in high yield (90-96%) by nitration of 1,3-dihydrobenzimidazol-2-one, as well as of 5,6-dinitro-and 4,5,6-trinitro-1,3-dihydrobenzimidazol-2-ones, with a small excess of concentrated nitric acid in a mixture with acetic anhydride and acetic acid at 50-60°C.* For communication I, see [1].