The crystal structure of quitenidinium ethyl ester ethyl sulfate, C(21
)H(27)N(2)O4(4)(+).C2H5SO4- has been determined. The conformation of t
he cation is open in contrast to the closed conformation of the non-pr
otonated quitenine ethyl ester. The molecules are linked by intermolec
ular O--H ... N hydrogen bonds into chains along the b axis. A bifurca
ted hydrogen bond is present between the protonated quinuclidine N and
two O atoms belonging to the ethyl sulfate anion.