Oxibendazole Explained
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
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).
Notes and References
- Theodorides VJ, Chang J, DiCuollo CJ, Grass GM, Parish RC, Scott GC . Oxibendazole, a new broad spectrum anthelmintic effective against gastrointestinal nematodes of domestic animals . The British Veterinary Journal . 129 . 6 . xcontdvii–scvi . December 1973 . 4779247 . 10.1016/s0007-1935(17)36351-0 .
- Book: Bowman DD . 280 . Chapter 6: Anti-parasitic Drugs . https://books.google.com/books?id=g_tBWVBevM0C&pg=PA280 . Georgis' parasitology for veterinarians. . 2009 . Saunders/Elsevier . St. Louis, Mo. . 978-1-4160-4412-3 . 9th.
