ethyl 2-(8-formyl-9-oxo-9,11-dihydroindolizino[1,2-b]quinolin-7-yl)butanoate

ethyl 7-(1-ethoxy-1-oxobutan-2-yl)-9-oxo-9,11-dihydroindolizino[1,2-b]quinoline-8-carboxylate

4-ethyl-3-hydroxy-3,4-dihydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-14(12H)-one