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Record Information
StatusExpected but not Quantified
Creation Date2012-09-11 17:52:29 UTC
Update Date2019-07-23 06:12:02 UTC
Secondary Accession Numbers
  • HMDB32887
Metabolite Identification
Common Name4-Amino-2-methyl-1-naphthol
Description4-Amino-2-methyl-1-naphthol, also known as vitamin K5 or 2-methyl-4-amino-1-naphthol, belongs to the class of organic compounds known as naphthols and derivatives. These are naphthalene derivatives carrying one or more hydroxyl (-OH) groups at any ring position. Oral lethal dose for the HCl salt in rats is 0.7 g/kg.4-Amino-2-methyl-1-naphthol HCl salt is a vitamin K and prevents bleeding caused by vitamin K deficiency when given via intravenous or intramuscular injections at doses of about 1–3 mg. 4-Amino-2-methyl-1-naphthol is a very strong basic compound (based on its pKa). Vitamin K function of the compound was first noted in 1940. Its hydrochloride (HCl) salt is often called vitamin K5. Latter is formed via oxidation and deamination of 4-amino-2-methyl-1-naphthol.4-Amino-2-methyl-1-naphthol can be made from 2-methylnaphthalene or menadione.4-Amino-2-methyl-1-naphthol HCl salt prevents the growth of different molds and bacteria. It darkens at 262 °C and decays without melting at 280–282 °C.HCl salt breaks down in aqueous solutions via oxidation which is quite fast at neutral pH. First a pink and later a purple precipitant forms. The colored precipitant is (4-oxy-2-methylnaphtylimine)-2-methyl-1,4-naphthoquinone, which is a condensation reaction product of 4-amino-2-methyl-1-naphthol and menadione. 4-Amino-2-methyl-1-naphthol is a menadione analog. HCl salt is water-soluble and its parenteral administration requires no emulsifiers unlike fat-soluble phylloquinone for example, which is often in formulations with lecithin or glycocholic acid. HCl salt has been studied as a potential treatment for cancer as it prevents glycolysis in cancer cells, which provides them energy for growth. Thus it has been studied as potential food preservative. Parenterally given 1 mg/ml aqueous solutions and orally taken 4 mg tablets of the HCl salt have been available commercially.4-Amino-2-methyl-1-naphthol HCl salt has a mass of 209.57 g/mol. The HCl salt has been used as a medicine for vitamin K deficiency under tradenames such as Synkamin, which was sold by Parke-Davis, but has since been discontinued.
1-Naphthalenol, 4-amino-2-methyl-, hydrochlorideHMDB
1-Naphthol, 4-amino-2-methyl-, hydrochloride (8ci)HMDB
2-Methyl-4-amino-1-naphthol hydrochlorideHMDB
4-Amino-2-methyl-1-naphthalenol, 9ciHMDB
4-Amino-2-methyl-1-naphthol hciHMDB
4-Amino-2-methylnaphthol hydrochlorideHMDB
4-Hydroxy-3-methyl-1-naphthylammonium chlorideHMDB
Synkamin hydrochlorideHMDB
Vitamin K5HMDB
Vitamin K5 hydrochlorideHMDB
4-Amino-2-methyl-1-naphthalenol, hydrochlorideMeSH
Vitamin K5, hydrochlorideMeSH
Chemical FormulaC11H11NO
Average Molecular Weight173.2111
Monoisotopic Molecular Weight173.084063979
IUPAC Name4-amino-2-methylnaphthalen-1-ol
Traditional Name4-amino-2-methylnaphthalen-1-ol
CAS Registry Number83-70-5
InChI Identifier
Chemical Taxonomy
Description belongs to the class of organic compounds known as naphthols and derivatives. These are naphthalene derivatives carrying one or more hydroxyl (-OH) groups at any ring position.
KingdomOrganic compounds
Super ClassBenzenoids
Sub ClassNaphthols and derivatives
Direct ParentNaphthols and derivatives
Alternative Parents
  • 1-naphthol
  • Organic nitrogen compound
  • Organic oxygen compound
  • Organopnictogen compound
  • Hydrocarbon derivative
  • Primary amine
  • Organooxygen compound
  • Organonitrogen compound
  • Amine
  • Aromatic homopolycyclic compound
Molecular FrameworkAromatic homopolycyclic compounds
External DescriptorsNot Available


Biological location:


Biological role:

Physical Properties
StateNot Available
Experimental Properties
Melting PointNot AvailableNot Available
Boiling PointNot AvailableNot Available
Water SolubilityNot AvailableNot Available
LogPNot AvailableNot Available
Predicted Properties
Water Solubility0.56 g/LALOGPS
pKa (Strongest Acidic)10.38ChemAxon
pKa (Strongest Basic)5.34ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count2ChemAxon
Hydrogen Donor Count2ChemAxon
Polar Surface Area46.25 ŲChemAxon
Rotatable Bond Count0ChemAxon
Refractivity54.23 m³·mol⁻¹ChemAxon
Polarizability18.99 ųChemAxon
Number of Rings2ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Spectrum TypeDescriptionSplash KeyView
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positivesplash10-00di-0900000000-6677c2f4f2ad22c0082cSpectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (1 TMS) - 70eV, Positivesplash10-00ec-7890000000-1b00de3c036af1a480dcSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-05fr-0900000000-32a317e92f65cb346309Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-05fr-0900000000-0f9658734f5e9a49bf8aSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0a4i-1900000000-99337b7ed86fcc70d9f2Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-00di-0900000000-f41821de00def2a3dd2fSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-00di-0900000000-facff9937db0e20a348cSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-0ab9-0900000000-e8d4f8a39e289fb6d764Spectrum
Biological Properties
Cellular Locations
  • Cytoplasm
  • Extracellular
Biospecimen LocationsNot Available
Tissue LocationsNot Available
Normal Concentrations
Not Available
Abnormal Concentrations
Not Available
Associated Disorders and Diseases
Disease ReferencesNone
Associated OMIM IDsNone
DrugBank IDNot Available
Phenol Explorer Compound IDNot Available
FoodDB IDFDB010869
KNApSAcK IDNot Available
Chemspider ID6497
KEGG Compound IDNot Available
BioCyc IDNot Available
BiGG IDNot Available
Wikipedia Link4-Amino-2-methyl-1-naphthol
METLIN IDNot Available
PubChem Compound6754
PDB IDNot Available
ChEBI IDNot Available
Food Biomarker OntologyNot Available
VMH IDNot Available
Synthesis ReferenceNot Available
Material Safety Data Sheet (MSDS)Not Available
General References
  1. (). Yannai, Shmuel. (2004) Dictionary of food compounds with CD-ROM: Additives, flavors, and ingredients. Boca Raton: Chapman & Hall/CRC.. .