1H-Pyrano(3',4':6,7)indolizino(1,2-b)quinoline-3,14(4H,12H)-dione, 4-ethyl-4-hydroxy-11-(hydroxymethyl)-, (S)-

(4S)-4-Ethyl-4-hydroxy-11-(hydroxymethyl)-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H,12H)-dione