Studies on cardiac ingredients of plants. IX. Chemical transformation of proscillaridin by utilizing its 1,4-cycloadducts as key compounds and biological activities of their derivatives
Three aromatic compounds (2-4) possessing a carbomethoxyl group or a dimethoxyphthaloyl group, prepared by the Diels-Alder reaction of the cardiac glycoside, proscillaridin (1), with dimethyl acetylenedicarboxylate and methyl propiolate, were transformed