Thiamine (C12H17N4OS+): structure, properties and hazards

Names and identifiers

IUPAC name: 2-[3-[(4-amino-2-methylpyrimidin-5-yl)methyl]-4-methyl-1,3-thiazol-3-ium-5-yl]ethanol
Synonyms: vitamin B1, aneurin, thiamin
+ 37 more
beriberi, Aneurin, Antiberiberi factor, Betaxin, thiaminium, Bewon, thiamine(1+) ion, Betabion, Thiaminal, Trophite, Vinothiam, Lixa-beta, Vetalin S, 3-[(4-amino-2-methylpyrimidin-5-yl)methyl]-5-(2-hydroxyethyl)-4-methyl-1,3-thiazol-3-ium, Vitamin B 1, Oryzanine, Thiamine, chloride, B-Amin, 2-[3-[(4-amino-2-methylpyrimidin-5-yl)methyl]-4-methyl-1,3-thiazol-3-ium-5-yl]ethanol, 3-(4-AMINO-2-METHYL-PYRIMIDIN-5-YLMETHYL)-5-(2-HYDROXY-ETHYL)-4-METHYL-THIAZOL-3-IUM, CHEBI:33283, Thiazolium, 3-((4-amino-2-methyl-5-pyrimidinyl)methyl)-5-(2-hydroxyethyl)-4-methyl-chloride, vitaminum b1, vitamin-b1, 2-(3-((4-amino-2-methylpyrimidin-5-yl)methyl)-4-methyl-1,3-thiazol-3-ium-5-yl)ethanol, 3-((4-amino-2-methylpyrimidin-5-yl)methyl)-5-(2-hydroxyethyl)-4-methyl-1,3-thiazol-3-ium, B1 Vitamin, PureVita Vitamin B1, RefChem:6301, Thiamine HCL 100 mg, Thiazolium, 3-((4-amino-2-methyl-5-pyrimidinyl)methyl)-5-(2-hydroxyethyl)-4-methyl-, chloride (1:1), DTXCID903648, CHEBI:26948, A11DA01, 2-(3-((4-amino-2-methyl-pyrimidin-5-yl)methyl)-4-methyl-1-thia-3-azoniacyclopenta-2,4-dien-5-yl)ethanol, 200-425-3, 3-((4-Amino-2-methyl-5-pyrimidinyl)methyl)-5-(2-hydroxyethyl)-4-methylthiazolium chloride
Molecular formula: C₁₂H₁₇N₄OS+
Empirical formula: C₁₂H₁₇N₄OS
Molecular weight: 265.36 g/mol
Exact mass: 265.11231
CAS number: 59-43-8
PubChem CID: 1130
Canonical SMILES: CC1=C(SC=[N+]1CC2=CN=C(N=C2N)C)CCO
Isomeric SMILES: CC1=C(SC=[N+]1CC2=CN=C(N=C2N)C)CCO
InChI: InChI=1S/C12H17N4OS/c1-8-11(3-4-17)18-7-16(8)6-10-5-14-9(2)15-12(10)13/h5,7,17H,3-4,6H2,1-2H3,(H2,13,14,15)/q+1
InChIKey: JZRWCGZRTZMZEH-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: Crystals from water[1]
Odor: SLIGHT, CHARACTERISTIC[1]
Melting point: MP: 248 °C, DECOMP (HYDROCHLORIDE)[1]
Solubility in water: SLIGHTLY SOL IN ALC & CHLOROFORM (MONONITRATE)[1]

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms: 18
Rings: 2
Aromatic rings: 2
Fraction sp³ carbons (Fsp3): 0.42
H-bond donors: 2
H-bond acceptors: 5
Rotatable bonds: 4
TPSA (Å²): 75.9 computed here · PubChem 104
Formal charge: 1
XLogP3: 1 PubChem
Complexity: 268 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C54.32%
H6.46%
N21.11%
O6.03%
S12.08%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: 0.61 Crippen (Wildman and Crippen 1999)
log S (water solubility): -2.06 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 3.22 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 265.36
log P ≤ 5 (Crippen): 0.61
H-bond donors ≤ 5: 2
H-bond acceptors ≤ 10: 5

Passes all four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

This chemical does not meet GHS hazard criteria for 100% (6 of 6) of all reports.[2]

Storage

The drug is not highly susceptible to atmospheric oxidation but should be protected from air and light. Thiamine hydrochloride tablets should be stored in tight, light-resistant containers at a temperature less than 40 degrees C, preferably between 15-30 degrees C. Thiamine hydrochloride injection should be protected from light and stored at a temperature less than 40 degrees C, preferably between 15-30 degrees C; freezing should be avoided.[1]

Safety data sheets on the supplier’s page: Vitas-M Laboratory, Shenghe Chemical, BOC Sciences.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[2]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[3]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[4]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[5]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
[6]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.

Similar structures

Thiamine pyrophosphate 64%

Tanimoto similarity on Morgan fingerprints (radius 2) with RDKit 2026.09, at least 45%.