A series of new benzothiazole derivatives 6a-h have been synthesized, in five steps, from substituted phenols via the 1,3,4-oxadiazole-2-thiones 5a-h. The in vitro antitumor activity of the compounds obtained was investigated and the benzothiazol derivatives 6d and 6e showed strong effects on leukaemia cell lines CCRF-CEM (CC50 = 12 ± 2 μmol L-1, 8 ± 1 μmol L-1, respectively). These compounds are leading candidates for further development. The title compounds were tested against representatives of several virus families containing single stranded RNA genomes, either positive-sense (ssRNA+), or negativesense (RNA-), and against double-stranded RNA genomes (dsRNA), as well as some Flaviviridae viruses.
