Synthesis and cytotoxic activity of 3-phenyl-2-thio-quinoxaline 1,4-dioxide derivatives in hypoxia and in normoxia.

A series of novel 3-phenyl-2-ethylthio/ethylsulfinyl/ethylsulfonyl/phenylthio/ phenylsulfonyl-quinoxaline 1,4-dioxide derivatives were synthesized and screened for their cytotoxicity in vitro on human leukaemia cell line HL-60, human esophagus cancer cell line ECA-109, human prostate cancer cell line PC-3, human gastric carcinoma cell line SGC-7901, and human breast cancer cell line MCF-7 in hypoxia and in normoxia. Half of tested compounds showed higher cytotoxic activity both in hypoxia and in normoxia. The mechanism of one potent compound, 67, in hypoxia showed that the mitochondria pathway is involved in the antitumor activity of this class of compounds.