(E)-6-benzylidene-4-ethyl-3,10-dioxo-3,4,6,7,8,10-hexahydro-1H-pyrano[3,4-f]indolizine-5-carboxylic acid

(8-acetoxymethyl-9-oxo-9,11-dihydro-indolizino[1,2-b]quinolin-7-yl)-acetic acid ethyl ester

4-ethyl-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-4-yl benzoate

ethyl (RS)-2-aminopent-4-enoate