SLU-PP-332

1 Identity

Not A peptide. Non-peptide small molecule: an acylhydrazone (N-acylhydrazone) formed from 4-hydroxybenzohydrazide and 2-naphthaldehyde, carrying a phenol, a hydrazide carbonyl, a C=N imine and a naphthalene ring. No amino acid, no peptide bond, no stereocenter, no chiral element of any kind; the only configurational feature is the E/Z geometry of the C=N bond. Its presence in peptide catalogs is a category error with practical consequences: peptide handling, storage and stability assumptions do not transfer to it, and neither does a peptide release panel. Reported as an agonist of the estrogen-related receptors, which are orphan nuclear receptors and, despite the name, do not bind estrogen. a phrase that originates in journalism about a mouse study and not in any regulatory or analytical document. and described in press coverage as an "exercise mimetic". Chemical name (E)-4-hydroxy-N'-(naphthalen-2-ylmethylene)benzohydrazide. CAS 303760-60-3, PubChem CID 5338394. Also traded inside an oral consumer blend with BAM15, which is a chemically unrelated small molecule.

Sequence

None, and none can exist. There are no amino acids and no peptide bond in this molecule. The full structural name is (E)-4-hydroxy-N'-(naphthalen-2-ylmethylene)benzohydrazide. Any document offering a sequence, an amino-acid analysis, a net peptide content or an endotoxin figure for this article has run a peptide template against a 290 Da small molecule and was not read by whoever signed it.

Molecular formula

C18H14N2O2. No sulfur, no halogen, no metal. The molecule is a condensation product and its principal chemical liability is the reverse reaction: hydrolysis of the C=N bond back to the two starting materials.

Average mass

290.322 Da (C18H14N2O2) on IUPAC 2021 abridged conventional atomic weights (C 12.011, H 1.008, N 14.007, O 15.999). Listings commonly print 290.32 g/mol, which agrees. The same formula on the pre-2021 table returns 290.316; the 0.006 Da spread is stated only so a purchaser comparing certificates across suppliers does not treat it as a discrepancy.

Monoisotopic mass

290.10553 Da neutral molecule; [M+H]+ 291.11280; [M-H]- 289.09825; [M+Na]+ 313.09475. A plus or minus 5 ppm identity window on the protonated ion is plus or minus 0.0015 Da. Mass is a weak identity test for this article on its own, because the E and Z geometric isomers and the naphthalen-1-yl regioisomer are all isobaric to the last decimal; identity is established by NMR against a certified reference standard and by retention-time co-elution, with mass as a confirmatory rather than a primary test.

Salt / variant note

Five confusables, and mass separates only two of them. (1) The Z geometric isomer of the same acylhydrazone — identical formula C18H14N2O2, identical mass to the last decimal, different compound. Acylhydrazones interconvert in solution under light and acid catalysis, so a lot certified as (E) can drift, and only NMR or a validated chromatographic method that resolves the two isomers can report the ratio. No supplier found states an E/Z ratio. (2) The naphthalen-1-yl regioisomer, again C18H14N2O2 and again isobaric; it is the cheaper starting aldehyde in some supply chains and is not detectable by mass at any resolution. Because both of those isomers are isobaric with the article to the last decimal, and no supplier page makes the point, a certified reference standard is a condition of purchase rather than a preference. (3) The two hydrolysis products, which are the degradation pathway rather than a substitution: 4-hydroxybenzohydrazide C7H8N2O2, 152.153 avg / 152.05858 mono, and 2-naphthaldehyde C11H8O, 156.184 avg / 156.05751 mono. Their sum exceeds the parent by 18.02 because hydrolysis adds water, and their appearance in a chromatogram is the direct readout of how the material was stored and handled. (4) BAM15, the co-formulated compound in a consumer oral blend, C16H10F2N6O, 340.294 avg / 340.08842 mono — a chemically unrelated fluorinated oxadiazolopyrazine, 49.97 Da heavier, and a blend certificate reports the blend rather than either component. (5) the category substitution, which is the commonest one in this market: the article sold and handled as though it were a peptide. Any certificate for this molecule bearing an amino-acid analysis, a net peptide content, a counterion assay or an endotoxin figure is describing a specification that does not apply, and a supplier who issues one has not looked at what they are selling.

2 Class & testing panel

Form

Single article

Testing panel

P6 — panel definition

3 Primary sources & evidence

The index reports the design and provenance of the literature, not a conclusion about effect.

Published literature exists, it is animal and in-vitro only, and it comes from essentially one laboratory group. The two primary reports are Billon and colleagues, ACS Chemical Biology 2023 (PMID 36988910, DOI 10.1021/acschembio.2c00720), mouse and in vitro; and Billon, Schoepke, Avdagic and colleagues, Journal of Pharmacology and Experimental Therapeutics 2024 (PMID 37739806, DOI 10.1124/jpet.123.001733), mouse, in male C57BL/6, diet-induced obese and ob/ob animals dosed at 50 mg/kg intraperitoneally twice daily for 28 days, shortened to 12 days in the ob/ob arm for tolerability reasons. Reported potency in cell-free and cell-based assays: EC50 98 nM at ERR alpha, 230 nM at ERR beta, 430 nM at ERR gamma. What does not exist: any human data of any kind, any human pharmacokinetic characterization, any registered human trial, and any formal toxicology package — no genotoxicity, no carcinogenicity, no reproductive or developmental toxicology, no cardiac safety assessment. The route in every published efficacy experiment is intraperitoneal injection twice daily, while the consumer market sells oral capsules and injectable-format vials, neither of which has published pharmacokinetic support in any species at the doses implied. The evidence grade carried on this article is D, and the estrogen-related receptors are expressed well beyond skeletal muscle, so the consequences of chronic systemic pan-ERR agonism are uncharacterized. The citation index page carries both primary reports with species, design, route, dose and duration badges and states the absences in the same typeface.

4 Storage & specification

Storage

Solid, stored at -20 degrees C, tightly closed, protected from light and moisture; suppliers state stability of four years or more under those conditions. Light protection is not boilerplate here — it is the specific control for E/Z photoisomerization of the acylhydrazone, and the label states the reason. Sparingly soluble: approximately 1-10 mg/mL in DMSO and 0.1-1 mg/mL in ethanol, with solvents purged with inert gas before dissolution. Solutions are prepared fresh and are not the storage form, because hydrolysis back to 4-hydroxybenzohydrazide and 2-naphthaldehyde is acid- and water-catalyzed. Suppliers classify the material as hazardous and specify that it must not be ingested or inhaled and that eye, skin and clothing contact be avoided; the GHS-compliant safety data sheet is reviewed before handling and is shipped with every lot.

Shelf life

Provisional 36-month retest interval at -20 degrees C, tightly closed and light-protected — longer than the peptide records in this catalog because the material is a crystalline small molecule rather than a lyophilized peptide, and shorter than the supplier's four-year claim because that claim is a vendor statement rather than a completed study on this company's container-closure system. Provisional pending a three-lot ICH Q1A-format study, long-term at the labeled condition with an accelerated arm, in which the E/Z ratio and the two hydrolysis products are the stability-indicating attributes and are trended together. The interval is set from data at the first pull that moves it and is shortened on data; it is never extended without a completed dataset.