Mn-Catalyzed Ligand-Free One-Pot Synthesis of (E)-6,7-Dihydrodibenzo[b,j][1,7]phenanthrolines and (E)-1,2,3,4-Tetrahydrobenzo[b][1,6]naphthyridines through Dehydrogenative Friedlander Annulation/C(sp3)-H Functionalization

An efficient, MnO2-catalyzed ligand-free synthesis of (E)-6,7-dihydrodibenzo[b,j][1,7]phenanthrolines, 13, and (E)-1,2,3,4-tetrahydrobenzo[b][1,6]naphthyridines, 15, utilizing, 2-amino-5-chloro-benzhydrol, 9, acridinol, 10, or 1-benzyl-4-piperidinol, 14, and benzyl alcohols, 11, is reported. The MnO2-catalyzed dehydrogenative Friedlander annulation utilizing ChCl/p-TSA (DES-1) and subsequent C(sp3)-H functionalization with TBAB/p-TSA (DES-2) was effected at 100 °C. The optimized reaction conditions gave excellent product yields, and the products were evaluated for their by UV absorption and fluorescence emission studies.

Design, synthesis, and biological evaluation of quinoline-piperazine/pyrrolidine derivatives as possible antileishmanial agents

In pursuance of our efforts to expand the scope of novel antileishmanial entities, a series of thirty-five quinoline-piperazine/pyrrolidine, and other heterocyclic amine derivatives were synthesized via a molecular hybridization approach and examined against intracellular amastigotes of luciferase-expressing Leishmania donovani. The preliminary in vitro screening suggests that twelve compounds in the series exhibited better inhibition against amastigote form with good IC50 values ranging from 2.09 to 8.89 μM and lesser cytotoxicity in contrast to the standard drug miltefosine (IC50 9.25 ± 0.17 μM). Based on the satisfactory selectivity index (SI), two compounds were tested for in vivo leishmanicidal efficacy against Leishmania donovani/golden hamster model. Compounds 33 and 46 have shown significant inhibition of 56.32%, and 49.29%, respectively, in vivo screening at a daily dose of 50 mg/kg for 5 days. The pharmacokinetic results confirmed that 33 and 46 have satisfactory IP exposure with adequate parameters. Collectively, Compound 33 was identified as the most significant potential lead that could be employed as a prototype for future optimizations.

Facile design of a WO3 nanorod-decorated graphene oxide 1D–2D nanocatalyst for the synthesis of quinoline and its derivatives

Graphene oxide supported WO3 nanorod as an efficient and recyclable catalyst for synthesis of Quinoline and its derivatives under solventless condition.

Bioorganopromoted green Friedländer synthesis: a versatile new malic acid promoted solvent free approach to multisubstituted quinolines

An efficient new strategy for the green synthesis of a variety of polysubstituted quinolines, using the Friedländer approach is reported, employing malic acid as a catalyst in organic synthesis for the first time.