SYNTHESIS AND ANTITUMOR ACTIVITY OF 4-(2-AMIDO-2-ETHOXYCARBONYL)ETHYLSULEENYL-4-DEOXY-4′-DEMETHYLEPIPODOPHYLLOTOXIN ANALOGUES

Twenty three 4-(2-amido-2-ethoxycarbonyl) ethylsulfenyl-4-deoxy-4'-demethylepipodophyllotoxin analogues were synthesized by three steps, in which trifluoroacetic acid was used as a condensation agent of 4'-demethylepipodophyllotoxin with L-cysteine ethyl ester hydrochloride without any protection of phenolic hydroxy and amino groups. All compounds were screened in vitro against L₁₂₁₀ leukemia and KB cells, in which, compounds 11, 16 and 18 exhibited more potent antitumor activity than etoposide.