Title: Carbimazole
CAS Registry Number: 22232-54-8
CAS Name: 2,3-Dihydro-3-methyl-2-thioxo-1H-imidazole-1-carboxylic acid ethyl ester
Additional Names: 1-ethoxycarbonyl-3-methyl-2-thio-4-imidazoline; ethyl 3-methyl-2-thioimidazoline-1-carboxylate; 1-methyl-3-carbethoxy-2-thioglyoxalone; athyromazole
Trademarks: Neo-mercazole (Roche); Neo-Thyreostat (Herbrand)
Molecular Formula: C7H10N2O2S
Molecular Weight: 186.23
Percent Composition: C 45.15%, H 5.41%, N 15.04%, O 17.18%, S 17.22%
Literature References: Thyroid inhibitor. Prepn: Rimington et al., US 2671088, reissued as US RE 24505; US 2815349 (1954, 1958, 1957, all to Natl. Res. Dev. Corp.); Baker, J. Chem. Soc. 1958, 2387. Clinical efficacy in Graves' disease: J. Duprey et al., Presse Med. 17, 1124 (1988).
Properties: Crystalline powder with characteristic odor; tasteless at first, followed by bitter taste; mp 122-125°. Sol (at 20°) in 500 parts of water; in 50 parts of ethanol; in 330 parts of ether; in 3 parts of chloroform; in 17 parts of acetone. uv max in 0.1N HCl : water (1:8): 291 nm; in 0.1N H2SO4: 227 nm and 291 nm (E1%1cm 557).
Melting point: mp 122-125°
Absorption maximum: uv max in 0.1N HCl : water (1:8): 291 nm; in 0.1N H2SO4: 227 nm and 291 nm (E1%1cm 557)
Therap-Cat: Antihyperthyroid.
Keywords: Antihyperthyroid.
Carbinoxamine Carbiphene Carbitol? Carbobenzoxy Chloride Carbocloral

Systematic (IUPAC) name
ethyl 3-methyl-2-sulfanylidene-imidazole-1-carboxylate
Clinical data
Trade names Neo-mercazole
AHFS/ International Drug Names
Legal status Prescription only
Routes oral
Pharmacokinetic data
Protein binding 85%
CAS number 22232-54-8 YesY
ATC code H03BB01
PubChem CID 31072
DrugBank DB00389
ChemSpider 28829 YesY
UNII 8KQ660G60G YesY
KEGG D07616 YesY
ChEBI CHEBI:617099 YesY
Chemical data
Formula C7H10N2O2S 
Mol. mass 186.233 g/mol
 YesY (what is this?)  (verify)

Carbimazole is used to treat hyperthyroidism. Carbimazole is a pro-drug as after absorption it is converted to the active form, methimazole. Methimazole prevents the thyroid peroxidase enzyme from coupling and iodinating the tyrosine residues on thyroglobulin, hence reducing the production of the thyroid hormones T3 and T4 (thyroxine).