(2S,6R,9S,12R,13S)-13-(tert-butyldimethylsiloxy)-12-isopropyl-6-methyl-2-[(E)-4-(tritylthio)but-1-enyl]-9-(tritylthiomethyl)-1-oxa-5,8,11-triazacyclopentadecane-4,7,10,15-tetraone

(1S,5S,6R,9S,20R,E)-5-(tert-butyldimethylsilyloxy)-6-isopropyl-20-methyl-2-oxa-11,12-dithia-7,19,22-triazabicyclo[7.7.6]docos-15-ene-3,8,18,21-tetraone