Synthesis and antileishmanial activity of new imidazolidin-2-one derivatives.

N(3)-acyl, arylsulfonyl and benzyl derivatives of N(1)-(4,6-dimethylpyridin-2-yl), (5-methylthiazol-2-yl) or (3-methylisoxazol-5-yl)imidazolidin-2-ones were synthesized and evaluated as potential antileishmanial agents. Determination of their cytotoxic effect was carried out using MRC5 cells. Two compounds, 1-(4,6-dimethylpyridin-2-yl)-3-(napht-2-ylsulfonyl)imidazolidin-2-one, 18, and 1-(3-methylisoxazol-5-yl)-3-(4-bromobenzyl)imidazo-lidin-2-one, 25, exerted significant antileishmanial activity in promastigotes of Leishmania (L) mexicana and Leishmania infantum, with IC(50) in the range of 8-16 micro mol L(-1). Antiparasitical activity of the less toxic compound, 25, was confirmed against intracellular amastigote of L. mexicana, the clinical relevant stage; its low IC(50) value (2.4 micro mol L(-1)) and its favourable toxicity/activity index (11) constitute encouraging results for ongoing pharmacomodulation in the corresponding subseries.