In a successful attempt to amplify the pharmacol. activity of the antimalarial bialamicol, substituents were introduced in the 2-position of the allyl side chains. 2-Fluoroallyl bromide, a versatile C3F building block, is described for the first time. While introduction of halogens did not alter the pharmacol. activity, addn. of HBr to the vinyl groups or substitution with Me induce a 500 and 100-fold increase of activity against Leishmania and Trypanosoma, resp. [on SciFinder (R)]