Chemical substance record

Cimetidine

51481-61-9C₁₀H₁₆N₆S252.347 g/mol

Organic/Inorganic Small MoleculeChEBI source record

A member of the class of guanidines that consists of guanidine carrying a methyl substituent at position 1, a cyano group at position 2 and a 2-{[(5-methyl-1H-imidazol-4-yl)methyl]sulfanyl}ethyl group at position 3. It is a H2-receptor antagonist that inhibits the production of acid in stomach. — ChEBI

Safety references

Safety documents & references

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Identity & molecular properties

Source-linked values

CAS number	51481-61-9	ChEBI ↗
Molecular formula	C₁₀H₁₆N₆S	ChEBI ↗
Molar mass	252.347 g/mol	ChEBI ↗
Monoisotopic mass	252.11572 Da	ChEBI ↗
Formal charge	0	ChEBI ↗
ChEBI identifier	CHEBI:3699	ChEBI ↗

Cross-source molecular data

PubChem

Molar mass	252.34 g/mol	PubChem ↗
Exact mass	252.11571571 Da	PubChem ↗
Computed XLogP	0.4	PubChem ↗
Topological polar surface area (Å²)	114	PubChem ↗
H-bond donors	3	PubChem ↗
H-bond acceptors	4	PubChem ↗
Rotatable bonds	7	PubChem ↗

PubChem computed values are shown separately from the ChEBI record. An exact InChIKey match was used to connect the records. Molecular descriptors do not describe a supplied product’s purity, particle size or performance.

Names & structural identifiers

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Source preferred name

cimetidine

IUPAC name

2-cyano-1-methyl-3-(2-{[(5-methyl-1H-imidazol-4-yl)methyl]sulfanyl}ethyl)guanidine

InChIKey

AQIXAKUUQRKLND-UHFFFAOYSA-N

SMILES

CN/C(=N/C#N)NCCSCc1ncnc1C

InChI

InChI=1S/C10H16N6S/c1-8-9(16-7-15-8)5-17-4-3-13-10(12-2)14-6-11/h7H,3-5H2,1-2H3,(H,15,16)(H2,12,13,14)

Names & synonyms

2-cyano-1-methyl-3-(2-{[(5-methyl-1H-imidazol-4-yl)methyl]sulfanyl}ethyl)guanidineCimetagcimetidinacimetidinumTagamet HB 200Ulcerfen

Names are supplied by ChEBI. Trade names and related synonyms may describe a broader product context.

Classification & relationships

ChEBI ontology

nitrileChEBI parent class · 18379 ↗aliphatic sulfideChEBI parent class · 22327 ↗guanidinesChEBI parent class · 24436 ↗imidazolesChEBI parent class · 24780 ↗

organosulfur compound organic heterocyclic compound organic molecular entity

Roles recorded in ChEBI

analgesicH2-receptor antagonistanti-ulcer drugP450 inhibitoradjuvant

Database role annotations describe reported biological or chemical roles; they are not product approvals or recommendations for use.

Mass ↔ amount of substance

Calculated from sourced mass

Amount

Input unit

Equivalent amount

0.0039628 mol

Uses 252.347 g/mol from ChEBI. Assumes the substance described by this record; no purity or concentration correction is applied.

Elemental composition

Theoretical mass fractions

C

Carbon · 10 atoms

47.60%

N

Nitrogen · 6 atoms

33.30%

S

Sulfur · 1 atom

12.71%

H

Hydrogen · 16 atoms

6.39%

Calculated theoretical mass fractions from the reported formula and PubChem periodic-table atomic masses. These are not assay or purity results.

Research & patent references

Selected source associations

The effect of multiple doses of cimetidine on the steady-state pharmacokinetics of quetiapine in men with selected psychotic disorders. ↗Journal of clinical psychopharmacology · 2002 Apr · PMID 11910267

Different effects of three transporting inhibitors, verapamil, cimetidine, and probenecid, on fexofenadine pharmacokinetics. ↗Clinical pharmacology and therapeutics · 2005 Jan · PMID 15637527

BE804144 · Patent reference ↗Patent cross-reference supplied by ChEBI. Association alone does not establish claim scope.

US3950333 · Patent reference ↗Patent cross-reference supplied by ChEBI. Association alone does not establish claim scope.

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Sources & record history

Checked 27 Sep 2026

Identity, formula, mass, synonyms & ontologyEMBL-EBI ChEBI · CHEBI:3699

Release 255, 9 September 2026. ChEBI three-star (manually annotated) source entry. View original record ↗ · CC BY 4.0

Additional molecular descriptorsNCBI PubChem · CID 2756 · retrieved 2026-09-27

PubCAS formats source data, connects references and computes explicitly labelled conversions. CAS cross-references are supplied by ChEBI; they do not constitute CAS verification or endorsement.

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