Almotriptan,an antimigraine agent,and its malate salt

The crystal structures of almotriptan {systematic name: N,N‐dimethyl‐2‐5‐(pyrrolidin‐1‐ylsulfonylmethyl)‐1H‐indol‐3‐yl]ethanamine}, C₁₇H₂₅N₃O₂S, and almotriptan malate {systematic name: N,N‐dimethyl‐2‐5‐(pyrrolidin‐1‐ylsulfonylmethyl)‐1H‐indol‐3‐yl]ethanaminium malate, C₁₇H₂₆N₃O₂S⁺·C₄H₅O₅^?, a novel selective serotonin 1B/D agonist, have been determined in order to gain further insight into the structure–activity relationships of triptans. The two structures differ in the orientation of their sulfonylpyrrolidine side chains. A comparison with other triptans reveals that molecules of almotriptan, sumatriptan, zolmitriptan and rizatriptan can adopt two principal conformations. N—H...N, N—H...O and O—H...O hydrogen bonds are responsible for the molecular packing.