The interest of imidazo[2,1-b]thiazole derivatives results from the discovery of anthelmintic and immunomodulator properties of levamisole, the levogyre enantiomeric form 6-phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole. So, several imidazothiazoles were synthetized to obtain a better activity. We prepared imidazo[2,1-b]thiazoles with functional oxygenated side chains in varied positions on the cycle : carboxylic acid and ester, ketone, alcohol or hydrazide. The start products were ethyl (2-aminothiazol-4-yl)acetate, 2-(2-aminothiazol-4-yl)-1-arylethanones, other substituted 2-aminothiazoles or the imidazolidine-2-thione and varied α-halo ketones, halo-β-diketones or halo-β-ketoesters. Frequently we observed a rearrangment with allylic transposition in alkaline middle. From certain compounds it is possible to obtain acids, alcohols and hydrazides. The introduction of oxygenated chain does not increase the immunostimulant activity comparatively with the levamisole.