Class III antiarrhythmic activity of novel substituted 4-[(methylsulfonyl)amino]benzamides and sulfonamides.

The synthesis and Class III antiarrhythmic activity of a series of 4-[(methylsulfonyl)amino]benzamides and sulfonamides are described. Selected compounds show a potent Class III activity and are devoid of effects on conduction both in vitro (dog Purkinje fibers) and in vivo (anesthetized dogs). Compounds having a 2-aminobenzimidazole group were found to be the most potent, and one compound having this heterocycle (5, WAY-123,398) was selected for further characterization.

Antimalarial activity of some novel derivatives of 2,4-diamino-5(p-chlorophenyl)-6-ethylpyrimidine (pyrimethamine).

Thirteen new analogs of 2,4-diamino-5(p-chlorophenyl)-6-ethylpyrimidine (Daraprim, pyrimethamine) in which the alph position of the 6-ethyl substituent was modified were prepared. The respective oxygens analogs (ketals, ketone, alcohol), the dimethyl hydrazone, and the nitrone displayed activities in the range of 1/4 to 1/16 that of pyrimethamine toward Plasmodium berghei in mice. The therapeutic ratios of some of these compounds may be slightly better than that of pyrimethamine.