A study on the epoxidation of methyl farnesoate using the title reagent has been carried out. In addition, dimethyldioxirane has shown to be a convenient reagenl for the synthesis of putative metabolites of juvenile hormone III, such as diepoxide 4, triepoxide 5 and epoxy diol 7. This reagent has also shown to be an excellent tool for perforrning the preparation of tritium labelled derivatives 4 and 7. Finally, molecular mechanics and NMR studies for the characterisation of cis and trans tetrahydrofuran derivatives 8a and 8b, compounds resulting from the acid or enzymatic hydrolysis of epoxy diol 7, are also reported.
Although initially considered as a catabolic intermediate of insect juvenile hormone III (JH Ill, 2) (see Scheme I), recent investigations carried out by Richard et al. 1 have shown that diepoxide 4 is produced by larval ring gland tissues of Drosophila melanogaster incubated wilh radiolabelled precursors. It also appears that compound 4 is predominant in adults of this insect species and it exhibits low juvenile hormone activity. These results prompted some of us to undertake a comparative study of the metabolism of JH III and its diepoxide in different biological malrices, such as D. melanogaster cell fractions and mammalian cytosolic epoxy hydrolase, to ascertain the role of epoxide metabolizing enzymes on these insect growth regulators 2. With that aim, availability of putative metabolites, such as epoxides 3, 4 and 7, and related derivatives (i.e. the tetrahydrofurans 8 and the tetrol 9), was required. In the course of the above study, preparation of lritiated compounds 4 and 7 was also needed.
In this context, we anticipated that dioxiranes could constitute convenient reagents for the above purpose. It has been shown that dimethyldioxirane in acetone solution 3 is an efficient oxygen transfer agent which reacts with a variety of organic moieties under mild neutral conditions 4. In particular, this reagent has found important applications for the 1291