Novel deazaflavin–cholestane hybrid compounds, 3′, 8′-disubstituted-5′-deazacholest- 2, 4-dieno [2, 3-g] pteridine-2′, 4′(3′ H, 8′ H)-diones, have been synthesized by condensation reaction between 6-(monosubstituted amino)-pyrimidin-2, 4 (1H, 3H)-diones and 2-hydroxymethylenecholest-4-en-3-one in presence of p-toluenesulfonic acid monohydrate and diphenyl ether. The antitumor activities against human tumor cell lines ( ...