Design, synthesis and biological evaluation of imidazo[1,2‐a]pyridine analogues or derivatives as anti‐helmintic drug

The Albendazole was used as the lead compound, which was modified by structural transformation and with alkyl groups. A total of 18 compounds ( 4a – 4r ) were designed and synthesized. The in vitro experiment results showed that compounds 4e , 4f , 4k , 4l , 4q and 4r had good inhibitory effect on egg and imago of roundworm. IC 50 of compound 4l to anti‐egg of roundworm was 0.65 ± 0.01 μmol/L and to anti‐imago of roundworm was 1.04 ± 0.01 μmol/L. At the same time, it showed that compound 4l had the best effect in vivo, and the rate of anti‐helmintic could reach more than 99%. The results of acute toxicity tests indicated that these compounds were with LD 50 > 2100 mg/kg by oral administration, so they were low toxicity compounds. In a word, compound 4l was most likely to be a new anti‐helmintic drug through screening in vitro and in vivo.