p. 1029
(1972)p. 4041 - 4050
(1984)6,7-Dimethoxy-3-[2-methyl-prop-(Z)-ylidene]-3,5-dihydro-furo[3,2-c]quinoline-2,4-dione
4-Hydroxy-7,8-dimethoxy-3-[2-methyl-prop-(E)-ylidene]-3H-furo[2,3-b]quinolin-2-one
(Z)-2-(4-Hydroxy-7,8-dimethoxy-2-oxo-1,2-dihydro-quinolin-3-yl)-4-methyl-pent-2-enoic acid
(4-Hydroxy-7,8-dimethoxy-2-oxo-1,2-dihydro-quinolin-3-yl)-acetic acid
diazomethane