5-Amino-6-methyl­quinolin-1-ium 3-carb­oxy­propano­ate

The asymmetric unit of the title salt, C(10)H(11)N(2) (+)·C(4)H(5)O(4) (−), consists of two independent 5-amino-6-methyl­quinolin-1-ium cations and two 3-carb­oxy­propano­ate anions. Both cations are protonated at the pyridine N atoms and are essentially planar, with maximum deviations of 0.026 (3) and 0.016 (2) Å. In the crystal, the cations and anions are linked via N—H⋯O and O—H⋯O hydrogen bonds, forming a layer parallel to the ab plane. In the layer, weak C—H⋯O hydrogen bonds and π–π stacking inter­actions, with centroid-to-centroid distances of 3.7283 (15) and 3.8467 (15) Å, are observed. The crystal structure also features weak C—H⋯O hydrogen bonds between the layers.