Synthesis of a new spiro organic peroxide is described. The peroxy bonds were incorporated into the substrate framework via an acid-catalyzed ketal exchange reaction using hydrogen peroxide as the source of peroxy linkage. The hydroperoxyl groups were then bonded at the OH ends via Hg（II）-induced electrophilic additions to the C-C double bonds, giving a novel sprio structure with one peroxy bond in each of the two six-membered rings. The ester functionalities in the side chains also make it possible to conduct further structural modifications.
Some attempts to employ the singlet oxygen generated from molybdate-catalyzed decomposition of hydrogen peroxide are presented. Reduction of ascaridole with diimide is also described, along with the preliminary results of the cleavage study using Fe-cysteinate as a simple model for Fe-S type redox species. There were strong indica-tions that S-alkylation occurred as observed in similar cleavage of the potent antimalarial qinghaosu.
A [1,2]dioxolane-type peroxide was synthesized and tested for its cleavage behavior with Fe2+-cysteinate as a simple model of biological redox species. No S-alkylation product was observed.
Several simple analogues of peroxyplakoric acid were synthesized by using Kobayashi＇s method to construct the key 1,2-dioxane core and tested in vitro for antimalarial activity. The scope and limitation of the method was also briefly examined.
N-Acyl-β-hydroxy-4-phenyl-oxazolidinethiones could be rapidly converted into their ethyl thiol esters in high yields by treatment with EtSH at 0 ℃ in CH3CN or 9 ： 1 （V ： V） THF-H2O in the presence of a catalytic amount of K2CO3.
Synthesis of a nitro analogue of plakoric acid is presented. The peroxy bond was incorporated into the substrate structure through a boron trifluoride etherate catalyzed methoxy-hydroperoxy group partial exchange reaction in diethyl ether with urea-hydrogen peroxide complex （UHP, a commercially available solid reagent） as the source of the hydrogen peroxide. Under the given conditions, only one of the two methoxyl groups underwent the MeO—— OOH exchange and the resulting hydroperoxy hemiketal proceeded directly to the end product through an intramolecular Michael addition of the hydroperoxyl group to the nitro group activated carbon-carbon double bond.
Blastmycinone, a degradation product of the antibiotic antimycin A, was synthesized with a TiCl4-mediated asymmetric aldolization as the key step. Some unexpected yet interesting chemistry was also observed.
