(organic chemistry) The antitumour antibiotic (6R,6aS)-2-[(2S,3R,4R,5S,6S)-3,4-dihydroxy-4,6-dimethyl-5-(methylamino)oxan-2-yl]oxy-4,6-dihydroxy-3-methyl-8-[(E)-prop-1-enyl]-5,6,6a,7-tetrahydropyrrolo[2,1-c][1,4]benzodiazepin-11-one