Studies on 2,3,N,N'-substituted 4,4'-diaminodiphenylsulfones as potential antimalarial agents

A series of new 4,4'-diaminodiphenylsulfones substituted at 2 and 3 position and also at primary amino group of the phenyl rings have been synthesized and evaluated for their antimalarial activity against Plasmodium berghei infection in mice. Some of these compounds were active and showed complete inhibition of parasitaemia which included 7a1-7a4, 7b3, 7b4 and 16a at 1 mg/kg i.p. for 4 days and 16a, at 0.3 mg/kg for 4 days. Some compounds tested for their synthetase inhibitory action in cell-free system isolated from P. berghei (7b1, 7b2 and 8b2) were found to be more active than diaminodiphenylsulphone. The difference in order of activity between these in vivo and in vitro tests may be due to differences in their pharmacokinetic properties.