(3S,10R,16S)-10-(3-CHLORO-4-METHOXYBENZYL)-3-ISOBUTYL-6,6-DIMETHYL-16-{(1S)-1-[(2R,3R)-3-PHENYLOXIRANYL]ETHYL}-1,4,DIOXA-8,11,DIAZACYCLOHEXADEC-13-ENE-2,5,9,12-TETRONE