BPAP (Benzofuranylpropylaminopentane)

What is BPAP (Benzofuranylpropylaminopentane)?

BPAP ((2R)-1-(1-benzofuran-2-yl)-N-propylpentan-2-amine, also called (−)-BPAP, R-BPAP and (−)-1-(benzofuran-2-yl)-2-propylaminopentane; CAS 260550-89-8) is a small synthetic benzofuran-2-yl alkylamine. It is the reference catecholaminergic/serotonergic activity enhancer (CAE/SAE): a compound that enhances impulse-propagation-mediated release of noradrenaline, dopamine and serotonin, with trace amine-associated receptor 1 (TAAR1) proposed as its target. BPAP is not a peptide and not an amino acid, even though it is often searched as a “BPAP peptide.” Its activity comes from a 2-propylaminopentane chain carried on a benzofuran ring, a tryptamine-like scaffold rather than an amphetamine-like one.

In electrically stimulated [³H]-transmitter release assays, (−)-BPAP significantly enhanced noradrenaline and dopamine release at 0.18 µmol/L and serotonin release at 36 nmol/L, with significant enhancement recorded at 10⁻¹⁴ to 10⁻¹² M in region-specific release assays (Knoll et al., 1999, PMC1571822). That is what BPAP does at the release-machinery level: it raises the amount of transmitter released per stimulus instead of releasing transmitter on its own.

Batch-verified at Modern Aminos, BPAP is supplied in one laboratory format:

• Liquid solution in a dropper bottle

Laboratories building neurochemistry and nootropic structure-activity panels often place BPAP next to other public reference listings such as 9-Me-BC, Bromantane and TAK-653, as well as Semax and Noopept. For a closer look at whether BPAP is a peptide and how it relates to PPAP, see Is BPAP a Peptide? Benzofuranylpropylaminopentane Explained.

Chemical and Molecular Data for BPAP (Benzofuranylpropylaminopentane)

Identity fields are drawn from PubChem CID 9816303 ((R)-enantiomer) and PubChem CID 9859674 (stereochemistry unspecified); the certificate is published in the Certificate of Analysis tab.

What are the Mechanisms of Action?

The biochemical targets and pathway logic of BPAP in laboratory research include:

• Catecholaminergic/serotonergic activity enhancer (CAE/SAE): BPAP enhances impulse-propagation-mediated release (exocytosis) of noradrenaline, dopamine and serotonin, the effect its developers named CAE/SAE activity. In electrically stimulated [³H]-transmitter release assays, (−)-BPAP significantly enhanced [³H]-noradrenaline and [³H]-dopamine release at 0.18 µmol/L and [³H]-serotonin release at 36 nmol/L, and region-specific release assays recorded significant enhancement at 10⁻¹⁴ to 10⁻¹² M (Knoll et al., 1999).
• Enhancement distinct from uptake or MAO inhibition: In the same stimulated-release format, 50 ng/mL (−)-BPAP was the most effective concentration for [³H]-noradrenaline and [³H]-dopamine release and 10 ng/mL for [³H]-serotonin. Selective noradrenaline and serotonin uptake inhibitors, selective MAO-A and MAO-B inhibitors, and dopamine receptor agonists did not reproduce the enhancement, which places the enhancer mechanism apart from uptake or MAO inhibition (Miklya and Knoll, 2003).
• TAAR1-linked vesicular release: (−)-BPAP potentiated stimulation-evoked [³H]dopamine release of vesicular origin through trace amine-associated receptor 1 (TAAR1) mediation and did not induce non-vesicular release, unlike an amphetamine-type releaser. The effect was traced to increased protein kinase C (PKC)-mediated phosphorylation, (−)-BPAP also increased VMAT2 operation, and the authors proposed separate TAAR1 binding sites for releaser and enhancer compounds (Harsing et al., 2022).
• Bell-shaped concentration–effect curves: (−)-BPAP increased stimulation-evoked [³H]dopamine and [³H]GABA release at 10⁻¹³ to 10⁻¹¹ mol/L with bell-shaped concentration–effect curves. The authors attributed the rising phase to TAAR1 agonism and proposed TAAR1 heterodimerization with dopamine D2 receptors for the declining phase (Harsing et al., 2025).
• Monoamine transporter inhibition at nanomolar concentrations: At far higher concentrations than its enhancer range, (−)-BPAP inhibits monoamine uptake at recombinant transporters, with IC₅₀ values of 42 nM (DAT), 52 nM (NET) and 640 nM (SERT). It did not show a tyramine-like releasing action and inhibited tyramine-induced noradrenaline release (Shimazu et al., 2003).
• Benzofuran scaffold and radical-trapping chemistry: BPAP came from replacing the phenyl ring of PPAP (1-phenyl-2-propylaminopentane) in a series of 65 newly synthesized compounds; its benzofuran ring makes it a tryptamine-derived rather than amphetamine-derived structure (Knoll et al., 1999; Yoneda et al., 2001). Molecular-orbital calculations found the benzofuran ring able to trap hydroxyl radicals at every ring atom except carbon 3, with activation energies of about 10 kcal/mol (Nakai and Yoneda, 2001).

What Does Published Research Show for BPAP?

Peer-reviewed literature on BPAP (Benzofuranylpropylaminopentane) and its (R)-enantiomer centers on structure-activity chemistry, synthesis, release-assay pharmacology, transporter binding, and TAAR1 signaling:

• Founding CAE/SAE characterization (PMC): (−)-BPAP was selected from 65 newly synthesized compounds as a reference compound for analyzing the CAE/SAE mechanism, with enhanced stimulated release of noradrenaline, dopamine and serotonin reported down to 10⁻¹⁴ M (PMC1571822).
• Structure-activity series (PubMed): A series of 1-aryl-2-alkylaminoalkanes structurally unrelated to β-phenylethylamine and the amphetamines was designed and prepared, and (−)-BPAP was the selected lead (PubMed 11377178).
• Enantioselective synthesis and absolute configuration (PubMed): Benzofuran was coupled with (R)-N-tosyl-2-propylaziridine or (R)-N-methoxy-N-methylnorvalinamide, and X-ray crystallography confirmed that (−)-BPAP has the R configuration (PubMed 11377179).
• Enhancer versus uptake and MAO inhibition (PubMed): Selective uptake inhibitors, MAO-A and MAO-B inhibitors, and dopamine receptor agonists did not reproduce the stimulated-release enhancement produced by 10 to 50 ng/mL (−)-BPAP (PubMed 12697274).
• Transporter pharmacology (PubMed): (−)-BPAP inhibited uptake at recombinant DAT, NET and SERT with IC₅₀ values of 42, 52 and 640 nM and showed no tyramine-like releasing action (PubMed 14659999).
• TAAR1 signaling (PMC): (−)-BPAP potentiated vesicular dopamine release through TAAR1 mediation and PKC-mediated phosphorylation (PMC9369307), with bell-shaped concentration–effect curves at 10⁻¹³ to 10⁻¹¹ mol/L in a later study (PMC11794408).
• Chemical Directory & Structure Verification (PubChem): (R)-enantiomer: CAS 260550-89-8, C₁₆H₂₃NO, 245.36 g/mol, InChIKey LJHIBIVAYHQPBT-CQSZACIVSA-N, UNII 5XG5HU8U55, DSSTox DTXSID701027206 (PubChem 9816303). Stereochemistry-unspecified record: InChIKey LJHIBIVAYHQPBT-UHFFFAOYSA-N (PubChem 9859674).
• Analytical Quality: Why chromatographic testing matters for reference materials is covered in Modern Aminos’ note on HPLC testing.

How does BPAP compare to other compounds?

To map enhancer, enzyme and receptor targets in monoamine neurochemistry, researchers compare BPAP against its phenyl parent, an MAO-B inhibitor, and other reference compounds, including several available at Modern Aminos:

Frequently Asked Questions (FAQs)