1H-Pyrano[3',4':6,7]indolizino[1,2-b]quinoline- 3,14(4H,12H)-dione, 4-ethyl- 11-[[[4-[[5,5a,6,8,8a,9-hexahydro-5-(4-hydroxy- 3,5-dimethoxyphenyl)-6-oxofuro[3',4':6,7]naphtho[2,3-d]- 1,3-dioxol-9-yl]amino]phenyl]imino]methyl]-4-hydroxy-, hydrochloride, stereoisomer NSC683556