Bridged 1,2,4-Trioxolanes: SnCl 4 -Catalyzed Synthesis and an In Vitro Study against S. mansoni .

A synthesis of bridged 1,2,4-trioxolanes (bridged ozonides) from 1,5-diketones and hydrogen peroxide catalyzed by SnCl 4 was developed. It was shown that the ratio of target ozonides can be affected by the application of SnCl 4 as a catalyst and varying the solvent. A wide range of bridged 1,2,4-trioxolanes (ozonides) was obtained in yields from 50 to 84%. The ozonide cycle was moderately resistant to the reduction of the ester group near the peroxide cycle to alcohol with LiAlH 4 . The bridged ozonides were evaluated for their antischistosomal activity . These ozonides exhibited a very high activity against newly transformed schistosomula and adult Schistosoma mansoni .