PREPARATION OF A CYCLOPROPANE-CONTAINING ANALOG OF ARTEMISININ

The structure of the 1,3-dipolar addition product of diazomethane with artemisinic acid [2), a biogenetic and synthetic precursor of artemisinin [1], was confirmed by X-my crystallography as having the 11S configuration as predicted by molecular mechanics calculations. The cyclic diazo product 4 was photo-or thermolyzed to give 13-methylartemisinate [8) and a cyclopropane-containing analogue 7 of 2. The analogue was utilized to prepare a cyclopropane-containing analogue 10 of 1, opening a new route to a variety of artemisinin analogues.