A. Bekhit, AdnanSimegniew, Yihenew2018-06-272023-11-062018-06-272023-11-062012-01http://etd.aau.edu.et/handle/123456789/4267Malaria and leishmaniasis are neglected tropical parasitic diseases affecting billons of people around the globe. Owing to their promising antimalarial and antileishmanial activities, seven novel 2-(substitutedstyryl)-3-aryl-4(3H)-quinazolinones were synthesized in good yields (65.2-86.4%) by using cyclization and condensation reactions. Structures for the synthesized compounds were determined using elemental microanalysis, IR, 1H NMR and 13C NMR (for compound IVb). The in vivo antimalarial and the in vitro antileishmanial activities of the synthesized compounds were evaluated using mice infected with P. berghi ANKA strain and L. donovani strain, respectively. The target compounds showed poor antimalarial activities with percent suppression of 29.10-44.39% which was not significantly different from the negative control group (P>0.05). All the synthesized compounds displayed superior antileishmanial activities (IC50 values, 0.0128-3.1085 μg/ml) as compared to the standard drug miltefosine (IC50 = 3.1911 μg/ml). (E)-2-(4-chlorostyryl)-3-p-tolyl-4(3H)-quinazolinone (IVb) is the compound with promising antileishmanial activities (IC50 = 0.0128 μg/ml) which is approximately 4 and 250 times more active than the standard drugs amphotericin B deoxycholate (IC50 = 0.0460 μg/ml) and miltefosine (IC50 = 3.1911 μg/ml), respectively. Key words: Quinazolines, Antimalarial activities, Antileishmanial activities.enQuinazolinesAntimalarial activitiesAntileishmanial activities.Thesis