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Chemical substance record

Chlormezanone

80-77-3C11H12ClNO3S273.741 g/mol

A 1,3-thiazine that is 1,3-thiazinan-4-one S,S-dioxide in which a hydrogen at position 2 is substituted by a 4-chlorophenyl group and the hydrogen attached to the nitrogen is substituted by methyl. A non-benzodiazepine muscle relaxant, it was used in the management of anxiety and in the treatment of muscle spasms until being discontinued worldwide by its manufacturer in 1996, due to rare but serious cutaneous reactions. — ChEBI

Safety references

Safety documents & references

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Identity & molecular properties

Source-linked values
CAS number80-77-3ChEBI ↗
Molecular formulaC11H12ClNO3SChEBI ↗
Molar mass273.741 g/molChEBI ↗
Monoisotopic mass273.02264 DaChEBI ↗
Formal charge0ChEBI ↗
ChEBI identifierCHEBI:3619ChEBI ↗

Cross-source molecular data

PubChem
Molar mass273.74 g/molPubChem ↗
Exact mass273.0226421 DaPubChem ↗
Computed XLogP1.1PubChem ↗
Topological polar surface area (Ų)62.8PubChem ↗
H-bond donors0PubChem ↗
H-bond acceptors3PubChem ↗
Rotatable bonds1PubChem ↗

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

Copy any identifier
chlormezanone
2-(4-chlorophenyl)-3-methyl-1,3-thiazinan-4-one 1,1-dioxide
WEQAYVWKMWHEJO-UHFFFAOYSA-N
CN1C(=O)CCS(=O)(=O)C1c1ccc(Cl)cc1
InChI=1S/C11H12ClNO3S/c1-13-10(14)6-7-17(15,16)11(13)8-2-4-9(12)5-3-8/h2-5,11H,6-7H2,1H3

Names & synonyms

2-(4-chlorophenyl)-3-methyl-1,3-thiazinan-4-one 1,1-dioxidechlormezanonachlormezanonum

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

Classification & relationships

ChEBI ontology

Roles recorded in ChEBI

anxiolytic drugantipsychotic agentmuscle relaxant

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
Equivalent amount
0.00365309 mol

Uses 273.741 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 · 11 atoms
48.26%
O
Oxygen · 3 atoms
17.53%
Cl
Chlorine · 1 atom
12.95%
S
Sulfur · 1 atom
11.72%
N
Nitrogen · 1 atom
5.12%
H
Hydrogen · 12 atoms
4.42%

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
Withdrawal of chlormezanone-containing products. ↗South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde · 1999 Feb · PMID 10191862
Interaction of chlormezanone enantiomers with rat liver microsomes. ↗European journal of drug metabolism and pharmacokinetics · 1999 Jan-Mar · PMID 10412893
GB815203 · Patent reference ↗Patent cross-reference supplied by ChEBI. Association alone does not establish claim scope.

Sources & record history

Checked 27 Sep 2026
EMBL-EBI ChEBI · CHEBI:3619

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

NCBI PubChem · CID 2717 · 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.