Structure of (R,R)-4-bromo-2-{4-[4-bromo-1-(4-toluenesulfonyl)-1H-pyrrol-2-yl]-1,3-dinitrobutan-2-yl}-1-(4-toluenesulfonyl)-1H-pyrrole, another ostensible by-product in the synthesis of geminal-dimethyl hydrodipyrrins

The crystal structure of (R,R)-4-bromo-2-{4-[4-bromo-1-(4-toluenesulfonyl)-1H-pyrrol-2-yl]-1,3-dinitrobutan-2-yl}-1-(4-toluenesulfonyl)-1H-pyrrole (1, C₂₆H₂₄Br₂N₄O₈S₂) is presented. The title compound was isolated in suitable yield as a by-product in our synthesis of geminal-dimethyl hydrodipyrrins. We observe an unforeseen enantiomeric resolution both in the bulk sample and the crystal of 1, with distinct C—H...O (C_methyl—H...O_nitro, C _{sp ³} —H...O_sulfonyl) interactions observed in the enantiomers present, along with other interactions, namely C_5-pyrrolyl—H...O_sulfonyl, forming a polymer along the crystallographic c-axis direction. Whilst pyrrolic fragments are well documented in the literature, little data is found surrounding the 1,3-dinitrobutane scaffold.