1-Phenyl-2-propylaminopentane (PPAP), also known as α,N-dipropylphenethylamine (DPPEA) and by the developmental code name MK-306, is an experimental drug related to selegiline which acts as a catecholaminergic activity enhancer (CAE).

[8][1][2][3][9][10] There has been interest in PPAP for potential clinical use in humans, including in the treatment of depression, attention deficit hyperactivity disorder (ADHD), and Alzheimer's disease.

[4] PPAP is classified as a catecholaminergic activity enhancer (CAE), a drug that stimulates the impulse propagation-mediated release of the catecholamine neurotransmitters norepinephrine and dopamine in the brain.

[11][5] Recent findings have suggested that known synthetic monoaminergic activity enhancers (MAEs) like PPAP, BPAP, and selegiline may exert their effects via trace amine-associated receptor 1 (TAAR1) agonism.

[13] The therapeutic index for PPAP in animal models is greater than that of amphetamine while producing comparable improvements in learning, retention, and antidepressant effects.

[4] It has been found to reduce deficits induced by the dopamine depleting agent tetrabenazine in the shuttle box learning test in rats.

[4][14][1][2][5][16] PPAP is similar in chemical structure to propylamphetamine (N-propylamphetamine; NPA; PAL-424), but has an α-propyl chain instead of an α-methyl group.

[32][33][34] The development of PPAP was critical in elucidating that the CAE effects of selegiline are unrelated to its monoamine oxidase inhibition.

[8][1][2][3][9] PPAP has been proposed as a potential therapeutic agent for attention deficit hyperactivity disorder (ADHD), Alzheimer's disease, and depression based on preclinical findings.