N,N-Bis(trifluoromethylquinolin-4-yl)diamino alkanes: synthesis and antimalarial activity.

A series of N,N-bis(trifluoromethylquinolin-4-yl)- and N,N-bis[2,8-bis(trifluoromethyl)quinolin-4-yl] diamino alkane and piperazine derivatives were synthesised by employing a simple and rapid displacement reaction of the 4-chloro group on the 2-trifluoromethyl- and 2,8-bis(trifluoromethyl)-quinoline by diaminoalkane or piperazine groups. Results of in vitro antimalarial activity evaluations of these compounds against the chloroquine-sensitive (D10) and chloroquine-resistant (K1) strains of Plasmodium falciparum indicate that compounds with trifluoromethyl groups in both the 2 and 8 positions coupled with diaminoalkyl bridging chains of 2 to 6 carbon atoms exhibit a slightly higher activity than compound with only a trifluoromethyl group at position 2, and those with a piperazine bridge. These compounds exhibit higher activity in the chloroquine-resistant than in the chloroquine-sensitive strains of the Plasmodium. Comparative studies indicate that the compounds are more selective in their cytotoxicity against the parasite cells. Except for compounds containing a piperazine bridge, this new series of compounds interact with ferriprotoporphyrin IX to more or less the same extent.

1,2,4-Triazino-[5,6b]indole derivatives: effects of the trifluoromethyl group on in vitro antimalarial activity.

In an attempt to search for new and alternative antimalarial agents, a series of unsubstituted and 6-trifluoromethyl-1,2,4-triazino[5,6b]indole and 5H-1,2,4-triazolo[1',5',2,3]-1,2,4-triazino[5,6b]indole derivatives were synthesized and their chemical structures confirmed by 1H NMR and 13C NMR, elemental, IR and mass spectrophotometric analyses. The in vitro antimalarial activities of these compounds were evaluated against the chloroquine-sensitive (D10) and the chloroquine-resistant (RSA11) strains of Plasmodium falciparum. The 1,2,4-triazino[5,6b]indole derivatives (4, 6 and 8) with a trifluoromethyl group at position 6 exhibit increased in vitro activity when compared to the unsubstituted analogues, which are all devoid of activity. The presence of the trifluoromethyl group in the 5H-1,2,4-triazolo[1',5',2,3]-1,2,4-triazino[5,6b]indole ring system leads to compounds with diminished antimalarial activity when compared to the corresponding unsubstituted analogues. The compounds associate with ferriprotoporphyrin IX and interact with DNA to more or less the same extent.