(3S,6S,9S,12R,15S,18S)-3,9-dibenzyl-6-[(1R)-1-hydroxyethyl]-12-(1H-indol-3-ylmethyl)-15-methyl-1,4,7,10,13,16-hexazabicyclo[16.3.0]henicosane-2,5,8,11,14,17-hexone