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Oxibendazole Synthesis
Oxibendazole is a benzimidazole drug that is used to protect against roundworms, strongyles, threadworms, pinworms and lungworm infestations in horses and some domestic pets. 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 Methyl chloroformate is the methyl ester of chloroformic acid. It is an oily colorless liquid, although aged samples appear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzimidazole
Benzimidazole is a heterocyclic aromatic organic compound. This bicyclic compound may be viewed as fused rings of the aromatic compounds benzene and imidazole. It is a colorless solid. Preparation Benzimidazole is produced by condensation of o-phenylenediamine with formic acid,. or the equivalent trimethyl orthoformate: :C6H4(NH2)2 + HC(OCH3)3 → C6H4N(NH)CH + 3 CH3OH 2-substituted derivatives are obtained when the condensation is conducted with aldehydes in place of formic acid, followed by oxidation.Robert A. Smiley "Phenylene- and Toluenediamines" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. Reactions Benzimidazole is a base: :C6H4N(NH)CH + H+ → [C6H4(NH)2CH]+ It can also be deprotonated with stronger bases: :C6H4N(NH)CH + LiH → Li [C6H4N2CH] + H2 The imine can be alkylated and also serves as a ligand in coordination chemistry. The most prominent benzimidazole complex features ''N''-ribosyl-dimethylbenzimidazole as found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
