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Cloxacillin chemical structure, C19H18ClN3O5S, CAS 61-72-3
2D chemical structure

Key facts

What buyers check first

CAS number
61-72-3
Formula
C19H18ClN3O5S
Molar mass
435.89 g/mol
Solubility
WHITE, CRYSTALLINE POWDER, SOL IN ALCOHOL, SLIGHTLY SOL IN ACETONE, CHLOROFORM, AQ SOLN…
HS code
294110
Category
Antibiotics and anti-infectives

What is Cloxacillin?

Plain description, key identifiers and synonyms

Cloxacillin is a semisynthetic penicillin antibiotic carrying a 3-(2-chlorophenyl)-5-methylisoxazole-4-carboxamido group at position 6. It has a role as an antibacterial agent and an antibacterial drug. It is a penicillin, a semisynthetic derivative and a penicillin allergen. It is functionally related to an oxacillin. It is a conjugate acid of a cloxacillin(1-).

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
(2S,5R,6R)-6-[[3-(2-chlorophenyl)-5-methyl-1,2-oxazole-4-carbonyl]amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid
CAS number
61-72-3 CAS number cross-checkedOther or deprecated CAS: 7081-44-9
EC numbers
200-514-7, 629-588-2
Molecular formula
C19H18ClN3O5S
UNII
O6X5QGC2VB
InChIKey
LQOLIRLGBULYKD-JKIFEVAISA-N
InChI
InChI=1S/C19H18ClN3O5S/c1-8-11(12(22-28-8)9-6-4-5-7-10(9)20)15(24)21-13-16(25)23-14(18(26)27)19(2,3)29-17(13)23/h4-7,13-14,17H,1-3H3,(H,21,24)(H,26,27)/t13-,14+,17-/m1/s1
Canonical SMILES
Cc1onc(-c2ccccc2Cl)c1C(=O)NC1C(=O)N2C1SC(C)(C)C2C(=O)O
Isomeric SMILES
CC1=C(C(=NO1)C2=CC=CC=C2Cl)C(=O)N[C@H]3[C@@H]4N(C3=O)[C@H](C(S4)(C)C)C(=O)O

Synonyms

  • Cloxacilline
  • Cloxacillinum
  • Cloxacilina
  • Methocillin S
  • Syntarpen
  • Clossacillina
  • Chloroxacillin
  • (3-(o-Chlorophenyl)-5-methyl-4-isoxazolyl)penicillin
  • 6-(3-(o-Chlorophenyl)-5-methyl-4-isoxazolecarboxamido)penicillanic acid
  • (2S,5R,6R)-6-[3-(2-chlorophenyl)-5-methyl-1,2-oxazole-4-amido]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid
  • 6-(((3-(2-Chlorophenyl)-5-methyl-4-isoxazolyl)carbonyl)amino)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid
  • 4-Thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid, 6-(3-(O-chlorophenyl)-5-methyl-4-isoxazolecarboxamido)-3,3-dimethyl-7-oxo-
  • (2S,5R,6R)-6-({[3-(2-chlorophenyl)-5-methylisoxazol-4-yl]carbonyl}amino)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid
  • 4-Thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid, 6-(3-(o-chlorophenyl)-S-methyl-4-isoxazolecarboxamido)-3,3-dimethyl-7-oxo-
  • cloxacillina
  • (2S,5R,6R)-6-(((3-(2-chlorophenyl)-5-methylisoxazol-4-yl)carbonyl)amino)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid
  • (2S,5R,6R)-6-(3-(2-chlorophenyl)-5-methyl-1,2-oxazole-4-amido)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid
  • Cloxacillin, Sodium
  • Sodium, Cloxacillin
  • cloxacillinum natricum
  • Tegopen
  • (2S,5R,6R)-6-[[3-(2-chlorophenyl)-5-methyl-1,2-oxazole-4-carbonyl]amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid
  • Cloxacillin (INN)
  • BRL 1621
  • Methylchlorphenylisoxazoryl-penicillin
Show all 32 synonyms
  • Tegopen (sodium monohydrate)
  • 4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid, 6-[[[3-(2-chlorophenyl)-5-methyl-4-isoxazolyl]carbonyl]amino]-3,3-dimethyl-7-oxo-, (2S,5R,6R)-
  • CXN
  • Orbenin (TN)
  • P-25 (sodium monohydrate)
  • CloxacillinNa
  • Cloxapen (sodium monohydrate)

Physical and chemical properties

Measured values and descriptors computed from the structure

Physical and chemical properties

Measured values, check the supplier specification for your grade

Solubility
WHITE, CRYSTALLINE POWDER, SOL IN ALCOHOL, SLIGHTLY SOL IN ACETONE, CHLOROFORM, AQ SOLN IS ALKALINE, DECOMP BETWEEN 170 °C & 173 °C, ODORLESS, BITTER TASTE /MONOHYDRATE/exp.

Values vary by grade. Ask suppliers for the COA or TDS of the batch you buy.

Computed descriptors

Calculated from the structure, useful for screening and formulation

Molecular weight
435.89 g/molcalc.
Exact mass
435.0656 Dacalc.
LogP (octanol/water)
2.55calc.
Topological polar surface area
112.7 Ųcalc.
Hydrogen bond donors
2calc.
Hydrogen bond acceptors
6calc.
Rotatable bonds
4calc.
Heavy atoms
29calc.
Rings
4calc.
Aromatic rings
2calc.
Fraction sp3 carbons
0.37calc.
Formal charge
0calc.
Stereocentres
3calc.
Lipinski rule of five
Passes (0 violations)calc.

Calculated for screening. Confirm critical figures with the supplier.

Murcko scaffold

The ring system that remains when every side chain is removed

Murcko scaffold of this chemical, O=C(NC1C(=O)N2CCSC12)c1conc1-c1ccccc1

O=C(NC1C(=O)N2CCSC12)c1conc1-c1ccccc1

4 rings, 22 atoms.

48 other chemicals share this scaffold

Safety and hazards

GHS classification summary, not a safety data sheet

GHS signal word
Danger
GHS07: Harmful or irritant
Harmful or irritant
GHS08: Serious health hazard
Serious health hazard

Hazard statements

  • H315Causes skin irritation.
  • H317May cause an allergic skin reaction.
  • H319Causes serious eye irritation.
  • H334May cause allergy or asthma symptoms or breathing difficulties if inhaled.
  • H335May cause respiratory irritation.
Precautionary statements (23)
  • P233Keep container tightly closed.
  • P260Do not breathe dust, fume, gas, mist, vapours or spray.
  • P261Avoid breathing dust, fume, gas, mist, vapours or spray.
  • P264Wash skin thoroughly after handling.
  • P264 + P265Wash skin thoroughly after handling. Do not touch eyes.
  • P271Use only outdoors or in a well-ventilated area.
  • P272Contaminated work clothing should not be allowed out of the workplace.
  • P280Wear protective gloves, protective clothing, eye protection and face protection.
  • P284In case of inadequate ventilation wear respiratory protection.
  • P302 + P352If on skin: Wash with plenty of water.
  • P304 + P340If inhaled: Remove person to fresh air and keep comfortable for breathing.
  • P305 + P351 + P338If in eyes: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
  • P319Get medical help if you feel unwell.
  • P321Specific treatment (see supplemental first aid instructions on the label).
  • P332 + P317If skin irritation occurs: Get medical help.
  • P333 + P317If skin irritation or rash occurs: Get medical help.
  • P337 + P317If eye irritation persists: Get medical help.
  • P342 + P316If experiencing respiratory symptoms: Get emergency medical help immediately.
  • P362 + P364Take off contaminated clothing. And wash it before reuse.
  • P403Store in a well-ventilated place.
  • P403 + P233Store in a well-ventilated place. Keep container tightly closed.
  • P405Store locked up.
  • P501Dispose of contents and container in accordance with local regulations.

GHS classification summary, not a safety data sheet (SDS). Classifications can differ by supplier, grade and concentration. Always check the supplier's SDS.

Full safety data and first aid

Cloxacillin suppliers

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Cloxacillin price

Indicative price range per kg from live supplier offers

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Uses and applications

What the substance is used for, by industry and function

Pharmacological actions

  • Anti-Bacterial Agents

Roles

  • antibacterial agent
  • antibacterial drug
  • antiinfective agent
  • antimicrobial agent
  • antimicrobial drug
  • pharmaceutical

Pharmacology

Cloxacillin is a semisynthetic beta-lactamase resistant penicillin antibiotic with antibacterial activity. Cloxacillin binds to and inactivates penicillin-binding proteins (PBPs) located on the inner membrane of the bacterial cell wall, thereby preventing the cross-linkage of peptidoglycans, which are critical components of the bacterial cell wall. This leads to an interruption of the bacterial cell wall and causes bacterial cell lysis.

How it is made

6-Aminopenicillanic acid is acylated with 3-(o-chlorophenyl)-5- methyl-4-isoxazolecarboxylic acid and the resulting cloxacillin (acid) is purified by recrystallizations and converted to the sodium salt (Sodium Cloxacillin USP)

Regulatory status

Inventories, regulations and trade controls that list this substance

Health and food

  • Active ingredient in FDA approved drug labels

HS code and trade data

Customs classification and reported world trade statistics

Global trade

World import and export statistics for the HS code Cloxacillin is traded under.

HS 2941.10Indicative HS code

Penicillins and their derivatives with a penicillanic acid structure, salts thereof

World exports in 2024
$1.66B
−2.5% vs 2023, imports $1.63B
2019 to 2024
Top exporters
  1. China56.8%
  2. Spain13.1%
  3. India * partner reported7.7%
Top importers
  1. India * partner reported16.4%
  2. Austria9.3%
  3. Brazil5.4%

* Partner reported figures, a lower bound.

Reported customs values in USD, not prices.Full trade data

The HS code shown for Cloxacillin is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

Quick answers about Cloxacillin, based on the data on this page

What is Cloxacillin?

Cloxacillin is a semisynthetic penicillin antibiotic carrying a 3-(2-chlorophenyl)-5-methylisoxazole-4-carboxamido group at position 6. It has a role as an antibacterial agent and an antibacterial drug. It is a penicillin, a semisynthetic derivative and a penicillin allergen. It is functionally related to an oxacillin.

What is the CAS number of Cloxacillin?

The CAS registry number of Cloxacillin is 61-72-3. Other or deprecated CAS numbers: 7081-44-9.

What is the molecular formula and weight of Cloxacillin?

The molecular formula of Cloxacillin is C19H18ClN3O5S and its molar mass is 435.89 g/mol.

What is Cloxacillin used for?

Known uses and roles of Cloxacillin include antibacterials and antibiotics in pharmaceuticals, antibacterial agent, antibacterial drug, antiinfective agent, antimicrobial agent and 3 more.

Is Cloxacillin hazardous?

Cloxacillin carries the GHS signal word "Danger". Main hazards: causes skin irritation, may cause an allergic skin reaction, causes serious eye irritation. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of Cloxacillin?

Cloxacillin is usually classified under HS code 294110 (Penicillins and their derivatives with a penicillanic acid structure, salts thereof). This is indicative, confirm it with your customs broker before shipping.

Where can I buy Cloxacillin?

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Where can I buy Cloxacillin in India?

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What is the price of Cloxacillin?

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Guides for buyers

Practical guides that help when you source, ship or handle Cloxacillin

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Data last updated 7 Oct 2026. Details may have changed, please confirm them with the supplier. Report an error on this page
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