Title: Clometocillin
CAS Registry Number: 1926-49-4
CAS Name: (2S,5R,6R)-6-[[(3,4-Dichlorophenyl)methoxyacetyl]amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid
Additional Names: 3,4-dichloro-a-methoxybenzylpenicillin; 6-(a-methoxy-3,4-dichlorophenylacetamido)penicillanic acid; clometacillin; clomethacillin
Manufacturers' Codes: no. 356; penicillin 356
Molecular Formula: C17H18Cl2N2O5S
Molecular Weight: 433.31
Percent Composition: C 47.12%, H 4.19%, Cl 16.36%, N 6.46%, O 18.46%, S 7.40%
Literature References: Semi-synthetic antibiotic related to penicillin. Prepn: Vanderhaeghe et al., Antimicrob. Agents Chemother. 1961, 581; US 3007920 (1961 to Recherche et Ind. Therap.). Activity studies: van Dijck et al., Antibiot. Chemother. 12, 192 (1962).
Derivative Type: Sodium salt
CAS Registry Number: 54530-86-8
Trademarks: Rixapen (RIT)
Molecular Formula: C17H17Cl2N2NaO5S
Molecular Weight: 455.29
Percent Composition: C 44.85%, H 3.76%, Cl 15.57%, N 6.15%, Na 5.05%, O 17.57%, S 7.04%
Properties: [a]D +210-220°. Pure epimers were prepared by fractional crystn. First crop: Crystals, dec 232-235°. [a]D20 +182° (water). Second crop: [a]D20 +207°. Third crop: Crystals, dec 180-183°. [a]D20 +261° (water). The free acid yields two diastereoisomers: [a]D +177° and [a]D +257°.
Optical Rotation: [a]D +210-220°; [a]D20 +182° (water); [a]D20 +207°; [a]D20 +261° (water); [a]D +177° and [a]D +257°
Therap-Cat: Antibacterial.
Keywords: Antibacterial (Antibiotics); ?Lactams; Penicillins.
Clomiphene Clomipramine Clomocycline Clonazepam Clonidine

Systematic (IUPAC) name
(2S,5R,6R)-6-([2-(3,4-dichlorophenyl)-2-methoxyacetyl]amino)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid
Clinical data
AHFS/ International Drug Names
Legal status  ?
CAS number 1926-49-4
ATC code J01CE07
PubChem CID 71807
ChemSpider 64831
KEGG D07236
Chemical data
Formula C17H18Cl2N2O5S 
Mol. mass 433.30622

Clometocillin (or clometacillin) is a penicillin.