2-[29-(2,3-dihydroxy-2-methylpropyl)-2-hydroxy-23-(1-hydroxyethyl)-6,26-dimethyl-4,7,19,22,25,28,31-heptaoxo-2,3,3a,4,5,6,7,8,9,10,18,19-dodecahydro-17H-18,9-(epiminoethanoiminoethanoiminoethanoiminomethano)pyrrolo[1',2':5,6][1,5,8,11]thiatriazacyclopenta