The crystal and molecular structure of chandonium dibromide: A synthetic bisquaternary aza steroidal neuromuscular blocking agent

The crystal and molecular structure of 17a-methyl-3-pyrrolidino-17a-aza-D-homo-5-androstene dimethyl bromide (HS818, chandonium dibromide). C26H46N2Br2, has been determined crystallographically by the heavy atom method and refined by full-matrix least-squares calculations toR =0.074 for 5045 reflections. The compound crystallizes in space groupP212121 witha=6.468(2),b=14.055(5),c=28.216(11) A. The N+...N+ inter-onium distance in chandonium bromide is 10.32 A, close to the distance of 10.29 A observed in chandonium iodide. Rings A, C, and D have a chair conformation and ring B is in a half-chair conformation. Ring E has a distorted envelope conformation. All rings in the steroid skeleton aretrans-connected.