(4R,8R,11S,18S)-4-benzyl-18-[(2S)-butan-2-yl]-11-methyl-6,13-dioxa-20-thia-3,10,17,22,23,24-hexaazatetracyclo[17.2.1.1~5,8~.1~12,15~]tetracosa-1(21),5(24),12(23),14,19(22)-pentaene-2,9,16-trione