5-AMINO-1MQ: structure, nomenclature and handling

The core is quinoline, a bicyclic aromatic system: a benzene ring fused to a pyridine ring, sharing an edge, with a single nitrogen atom in the six-membered ring on one side. It is a common scaffold in organic chemistry and entirely unlike the amino acid chains that make up most of this catalogue.

Two modifications define the compound. The name states both. The 1MQ portion means a methyl group on the ring nitrogen — position 1 — and that methylation is the structurally decisive change. A neutral quinoline nitrogen carries a lone pair and can accept a proton depending on pH; adding a methyl group makes the nitrogen quaternary, giving it four bonds and a permanent positive charge that no change in pH will remove. The molecule is a quinolinium cation rather than a neutral base.

The 5-amino portion is an amine group at position 5 of the fused ring system. It is electron-donating, and its effect on the aromatic system's electron distribution is what distinguishes this compound from the unsubstituted methylquinolinium.

The cation itself has a molecular weight near 159 daltons — small even by the standards of small molecules, and roughly a fifth of the lightest peptide in this catalogue.

The material is catalogued as 5-amino-1MQ, 5-amino-1-methylquinolinium, and 5-amino-1-methylquinolinium iodide where the salt form is stated. Systematic names describe the same cation.

The salt form is the part of the naming that carries real information. Because the cation is permanently charged, it is always supplied paired with an anion, and iodide is the common one for this compound. The iodide salt weighs approximately 286 daltons against the cation's 159 — so a nominal 10 mg of the salt contains substantially less of the active cation than 10 mg of bare cation would, if bare cation were a thing that could be weighed out. A chloride or bromide salt of the same cation would give a third and fourth figure again.

This is the same counter-ion arithmetic that peptide certificates address through net peptide content, arriving from a different direction. Listings that state a milligram figure without stating the salt form leave that arithmetic unresolved.

Nuclear magnetic resonance spectroscopy is the primary structural method here, as it is for small molecules generally. It reports directly on where substituents sit on the ring system — which position carries the amine, and whether the methyl group is on the nitrogen rather than a carbon — questions a mass measurement cannot answer, since positional isomers are identical in mass.

Mass spectrometry confirms the cation mass near 159 daltons. Note that a charged species behaves distinctively in the instrument: the cation is already ionised, so it is detected directly rather than requiring the protonation step that neutral molecules undergo.

High-performance liquid chromatography yields the purity figure in the familiar way. The aromatic system absorbs strongly in the ultraviolet, so detection is straightforward — this is not a compound with the weak-absorbance problem that affects peptides lacking aromatic residues. Residual solvent and heavy metal figures, where reported, are the small-molecule equivalents of the process checks a peptide certificate covers differently.

HEEZ Research supplies 5-AMINO-1MQ in a single format: a 10 mg lyophilized vial. There is no second strength in the current catalogue, so the format decision that arises with two-size products does not apply here.

The material is supplied as a dried solid. What a nominal 10 mg represents depends on the salt form, as described above, which is stated on the batch certificate.

Reconstitution converts the dried solid into a working solution, and it is a standard laboratory step rather than a product specification. Which solvent is used, and at what final concentration, is determined by the protocol in force at the receiving facility.

What HEEZ specifies is the contents of the vial: lyophilized 5-AMINO-1MQ in a single 10 mg format, stated on the label and on the batch certificate of analysis. Where a protocol is expressed in molar rather than mass terms, the additional figures it needs are the molecular weight and the salt form, both of which the certificate records.

Solubility behaviour follows from the permanent charge. Quaternary ammonium salts are generally water-soluble and, unlike peptides, their solubility does not vary with pH — there is no isoelectric point to work around, because the charge cannot be neutralised. The molecule is also small enough that aggregation, the dominant concern for peptides and proteins, does not arise at all.

Sealed material is ambient-stable for the duration of transit, so no cold chain or insulated packaging is required for shipping. On receipt the vial goes to refrigeration and is kept out of direct light.

Light protection matters here for a specific reason: iodide salts are photosensitive, and the anion oxidises on exposure to light to give free iodine, which discolours the solid or solution yellow to brown. That discolouration is a visible signal of the counter-ion degrading rather than the cation, but it is a reason to keep the material covered and to note the appearance of the solid on receipt.

The aromatic amine is the other group warranting attention. Aromatic amines oxidise slowly on exposure to air, particularly in solution, so solutions are made up as needed rather than held, and repeated freeze-thaw cycling is avoided.

The certificate records what an independent facility measured for one specific batch. Its value lies in being batch-specific, so the first check is that the lot number on the document matches the vial in hand.

The identity section should state the salt form explicitly and report a mass consistent with it. A figure near 159 daltons describes the cation; a figure near 286 describes the iodide salt. Both are correct statements about the same product, and knowing which was measured is what makes the number usable.

Where an NMR spectrum is included, it is the document that establishes substitution positions. For a small molecule it settles what a mass measurement settles for a peptide, because isomers of identical mass are otherwise indistinguishable.

The purity figure is the chromatographic main-peak area as a percentage of total peak area. Residual solvent and heavy metal figures, where reported, describe manufacturing cleanliness rather than the molecule itself.