Chemistry:Oxibendazole

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Short description: Chemical compound
Oxibendazole
Oxibendazole.svg
Clinical data
AHFS/Drugs.comInternational Drug Names
ATCvet code
Legal status
Legal status
  • Veterinary use only
Identifiers
CAS Number
PubChem CID
ChemSpider
UNII
KEGG
Chemical and physical data
FormulaC12H15N3O3
Molar mass249.270 g·mol−1
3D model (JSmol)
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Oxibendazole is a benzimidazole drug that is used to protect against roundworms, strongyles, threadworms, pinworms and lungworm infestations in horses and some domestic pets.[1][2] It is usually white to yellowish in appearance, and may take the form of a powder, tablet or paste.

Synthesis

Oxibendazole synthesis:[3]

4‑Hydroxyacetamide (1) is alkylated with n-propyl bromide in the presence of potassium hydroxide to give the ether (2). Nitration of this product with nitric and sulfuric acids proceeds at the position ortho to the amide group (3), which is then reduced with SnCl2 to yield the phenylenediamine derivative (4). Reaction of that intermediate with S-methyl isothiourea proceeds first by aromatic cyclisation to the guanidine derivative followed by elimination of methyl mercaptan to yield the 2-aminobenzimidazole system (5). Acylation with methyl chloroformate results in the formation of a urethane on the amino group to produce oxibendazole (6).

References

  1. "Oxibendazole, a new broad spectrum anthelmintic effective against gastrointestinal nematodes of domestic animals". The British Veterinary Journal 129 (6): xcontdvii–scvi. December 1973. doi:10.1016/s0007-1935(17)36351-0. PMID 4779247. 
  2. "Chapter 6: Anti-parasitic Drugs". Georgis' parasitology for veterinarians. (9th ed.). St. Louis, Mo.: Saunders/Elsevier. 2009. p. 280. ISBN 978-1-4160-4412-3. https://books.google.com/books?id=g_tBWVBevM0C&pg=PA280. 
  3. "Anthelmintic compositions containing benzimidazole derivatives" GB patent 1123317, published 1968-08-14, assigned to Smith Kline French Labs; Actor PP, Pagano JF, "Anthelmintic compositions and methods employing esters of benzimidazolyl carbamic acids and their thio analogs", US patent 3574845, issued 13 April 1971, assigned to Smith Kline and French Laboratories Ltd