Pseudotropine (ψ-tropine, or psi-tropine) is an isomer of tropine. Pseudotropine is formed during NADPH-dependent reduction of the 3-carbonyl group of tropinone to a beta-hydroxyl group. Tropinone reductase-II is an enzyme responsible for this transformation. It is known, that tropinone reductase-II is also a key enzyme in the biosynthetic pathway of tropane alkaloids, which include medicinally important compounds such as hyoscyamine (atropine) and cocaine.