6-Hydroxy-1,2,4-trioxanes, synthesis

Hydroxyphenyl)propionic acid, hydrogen peroxide determination, 639 6-Hydroxy-l,2,4-trioxanes, synthesis, 288 Hypercholesterolemia, reactive oxygen species in blood, 612... 

Using various derivatives of artemisinic acid, the methodology onthned in Scheme 184 was extended to the synthesis of a nnmber of modified artemisinin-type tetracychc trioxanes. For example, the syntheses of 6,9-desdimethylartemisinin 586a , A-fi-hydroxyartemisinin , and C9-alkylated artemisinin analognes were reported . In some cases it is possible to avoid the lactonization step while preserving the ester fnnctionality and interrnpting the cychzation of aldehyde-peroxyhemiacetals of type 652, at the step of formation of tricyclic 5-hydroxy-1,2,4-trioxane . ... 

Trioxanes. A general synthesis of 1,2,4-trioxanes involves treatment of an a-hydroxy hydroperoxide (I) and an epoxide such as 2 with WO, and catalytic amounts of chlorosulfonic acid yields of 1,2,4-trioxanes are 7 63%. ... 

Endoperoxides (also 1,2-dioxetanes) are versatile starting materials for further transformations. In view of the weak 0-0 bond, these peroxides are thermally sensitive to homolytic cleavage, a feature that makes most of them ha2aidous. Ring opening opens up attractive opportunities for selective transformations that include reductions (diols), oxidations (dicarbonyl products), rearrangements (hydroxy carbonyl compounds, epoxy carbonyl compounds, fo/s-epoxides, ene diones, etc.) and additions (polycycKc dioxanes or trioxanes, some of which display antimalarial activity). The synthesis and the subsequent reactions of the 2,3-dioxabicyclo[2.2.2]oct-7-en-5-one skeleton have been studied by Adam etak An impressive number of chemical transformations and examples for applications in organic synthesis have been collected in several reviews. 

---