Methyl 6-(phenylsulfinyl)imidazo[1,2-a]pyridine-2-carbamate, a potent, new anthelmintic.

A series of methyl imidazo-[11,2-a]pyridine-2-carbamates was synthesized for anthelmintic testing. The preparation of this class of compounds was simplified by utilization of a novel one-step condensation of the appropriately substituted 2-aminopyridine and methyl chloroacetylcarbamate. The most potent compound, methyl 6-(phenylsulfinyl)-imidazo[1,2-a]pyridine-2-carbamate, was orally effective against a broad range of helminths in sheep and cattle, at a dosage of 2.5 mg/kg. Limited trials in swine and dogs demonstrated anthelmintic activity at higher dosages. Limited observations in sheep and cattle indicated that, in both species, a single oral dose of 200 mg/kg was well tolerated.