Bis(4-hy-droxy-N-isopropyl-N-methyl-trypt-ammo-nium) fumarate: a new crystalline form of miprocin.

The title compound, bis-(4-hy-droxy-N-isopropyl-N-methyl-tryptammonium) (4-HO-MiPT) fumarate (systematic name: bis-{[2-(4-hy-droxy-1H-indol-3-yl)eth-yl](meth-yl)propan-2-yl-aza-nium} but-2-enedioate), 2C14H21N2O+·C4H2O4 2-, has a singly protonated tryptammonium cation and one half of a fumarate dianion in the asymmetric unit. The tryptammonium and fumarate ions are held together in one-dimensional chains by N-H⋯O and O-H⋯O hydrogen bonds. These chains are a combination of R 4 2(20) rings, and C 2 2(15) and C 4 4(30) parallel chains along (110). They are further consolidated by N-H⋯π inter-actions. There are two two-component types of disorder impacting the tryptammonium fragment with a 0.753 (7):0.247 (7) occupancy ratio and one of the fumarate oxygen atoms with a 0.73 (8):0.27 (8) ratio.