Facile and improved synthesis of 4β-aminopodophyllotoxin congeners

An efficient synthesis of 4β-aminopodophyllotoxin from 4β-bromopodophyllotoxin using ammonia, and also a facile synthesis of 4β-amino-4′-O-demethylpodophyllotoxin from 4β-azidopodophyllotoxin by simultaneous azido reduction and selective demethylation at 4′-position employing chlorotrimethylsilane and sodium iodide, has been described. These are potential precursors for the various 4β-amino analogs of podophyllotoxin possessing DNA topoisomerase II inhibition activity.