Dipeptides of O-methyl-L-threonine as potential antimalarials

L-Leucyl-O-methyl-L-threonine, O-methyl-L-threonyl-L-leucine, and O-methyl-L-threonyl-O-methyl-L-threonine were prepared and compared with O-methyl-L-threonine and L-leucine for antimalarial activity against Plasmodium berghei in mice. O-Methyl-L-threonine significantly prolonged survival time at doses of 160, 320, and 640 mg/kg. O-Methyl-L-threonyl-O-methyl-L-threonine was less active, significantly prolonging survival time only at 640 mg/kg. L-Leucine, as well as the other two dipeptides, exhibited no activity in this test.