R. R 'our attention has been focused mainly on variations in R'. For the most part, R has been halogen, alkyl, and alkoxy, and R” has been varied to include CH, Cl, CHCl, and CC1,. In practically all cases, the presence of a dichloroacetyl group was found to be essential for optimal activity. The variations in R were not as critical. One of the more active members of this new class of antiamoebic agents, AT-(2, 4-dichlorobenzyl)-N-(2-hydroxyethy1)- ...