Synthesis and antimalarial activity of novel chiral and achiral benzenesulfonamides bearing 1, 3, 4-oxadiazole moieties

Figures & data

Scheme 1 (i) NaOH (5% aqueous), ether, stirring at RT, 6 h (ii) H₂SO₄ / ethanol, refluxing, 11 h (iii) NH₂-NH₂.H₂O / ethanol (absolute), refluxing, 9 h (iv) CS₂ / KOH, ethanol, refluxing, 16-17 h (v) Et₃N, DMAP, CHCl3 (dry), benzyl bromide or p-nitrobenzyl bromide, stirring at 30–70°C, 5–7 h.

Table I.  Effects of compounds on the hem crystallization and hemoglobin proteolysis.

Compound	% IHC*	% IHbP*
4d	< 5	35.30 ± 1.90
4e	< 5	18.22 ± 1.04
4h	< 5	54.15 ± 2.26
5a	< 5	29.08 ± 3.55
5b	< 5	< 10
5c	< 5	36.05 ± 1.55
5d	< 5	35.30 ± 1.90
5e	< 5	27.54 ± 1.51
5f	< 5	28.45 ± 0.78
5g	< 5	38.16 ± 3.12
5h	< 5	34.15 ± 1.82
5i	< 5	25.33 ± 0.94
6c	< 5	28.45 ± 0.78
6d	< 5	27.54 ± 0.82
6h	< 5	12.16 ± 2.56
CQ	86.6 ± 2.75	NA

*IHC: Inhibition of hem crystallization. IHbP: Inhibition of hemoglobin proteolysis.

Figure 1 Parasitaemias at 4th day post-infection (%P). Mice were infected with 1x10⁷ infected red blood cells and treatment was administered 2 hours after infection (20 mg/kg) every 24 h for 4 consecutive days. Results are expressed as the media ± SEM. * p < 0.05. n = 6. Compound 03 = 4h.