[Dihydro-5,6-imidazo[2,1-b]thiazoles, dihydro-2,3-imidazo[2,1-b]benzothiazoles, analogs of levamisole].

New compounds containing 5,6-dihydro imidazo[2,1-b]thiazole, 2,3,5,6-tetrahydro imidazo[2,1-b]thiazole and 2,3-dihydro imidazo[2,1-b]benzothiazole rings, substituted by heterocycles analogue to chromones, were synthesized and screened against three nematodes, in vitro. The results indicate moderate anthelmintic properties, compared to levamisole; nevertheless, some products exhibit a significant degree of activity.