A synchrotron study of (2R,5′S)‐5′‐benzyl‐5‐bromo‐6‐methoxyspiro[indane‐2,2′‐piperazine]‐3′,6′‐dione dimethylformamide solvate

Synchrotron radiation was used to study the structure of the title compound, C₂₀H₁₉BrN₂O₃·C₃H₇NO, which was obtained as fine fragile needle‐shaped crystals by recrystallization from dimethylformamide (DMF), one molecule of which is incorporated per asymmetric unit into the crystal. The compound adopts a compact closed conformation with the orientation of the benzyl group such that the aryl ring is positioned over the piperazinedione ring, resulting in a C_spiro...C_trans—C—C_Ph pseudo‐torsion angle of ?3.3 (3)°. The five‐membered ring is present in an expected envelope conformation and the six‐membered piperazinedione ring adopts a less puckered boat‐like conformation. Reciprocal amide‐to‐amide hydrogen bonding between adjacent piperazinedione rings and C—H...O interactions involving DMF molecules propagate in the crystal as a thick ribbon in the a‐axis direction.