2,3-Disubstituted-1,4-naphthoquinones, 12H-benzo[b]phenothiazine-6,11-diones and related compounds: synthesis and biological evaluation as potential antiproliferative and antifungal agents.

A series of 2-chloro-3-arylsulfanyl-[1,4]naphthoquinones (2), 2,3-bis-arylsulfanyl-[1,4]naphthoquinones (3) and 12H-benzo[b]phenothiazine-6,11-diones and their analogs 6-8 were synthesized and evaluated for their antiproliferative activity against human cervical cancer (HeLa) cells. Compounds 3a and 3b were found to possess most potent antiproliferative and cell killing ability. Compounds 1-8 were also evaluated for antifungal activities. The structure-activity relationship of these compounds was studied and the results show that compound 2a (MIC(50)=1.56 microg/mL) exhibited in vitro potent antifungal activity compared to the clinically useful antifungal drug Fluconazole (MIC(50)=2.0 microg/mL) against Sporothrix. schenckii. Compound 2a (MIC(50)=1.56 microg/mL) also exhibited same antifungal activity compared to clinically useful drug Amphotericin-B (MIC(50)=1.56 microg/mL) against Trichophyton. mentagraphytes.