In the present work, we have synthesized novel quinoline-conjugated 1,2,3-triazole derivatives 6a-l starting from substituted acetanilides in five steps. The synthesized compounds were screened for their antileishmanial activity. Quinoline-conjugated 1,2,3-triazole compounds 6c (IC 50 = 15.1 μg/ml), 6d (IC 50 = 14.6 μg/ml) and 6e (IC 50 = 14.3 μg/ml) displayed potent antileishmanial activity when compared with standard sodium stibogluconate (IC 50 = 14.3 ± 1.5 μg/ml). A molecular docking study against Leishmania major pteridine reductase (Lm-PTR1) suggests that these compounds have the potential to become lead molecules in antileishmanial drug discovery.

This paper describes a method for the racemization of unwanted (S)-1 isomer arising from the resolution of (±)-1. The process of racemization involves thiyl radical-mediated reversible hydrogen abstraction at the chiral center, in the presence of AIBN in water. The racemized isomer was subsequently resolved by L-(+)-tartaric acid to get (R)-1, a histamine H 3 receptor pharmacophore. We foresee that such an approach of racemization will be industrially useful for recycling waste (S)-1 enantiomer.