Priyankar Paira

Amberlite-IRA-402 (OH) ion exchange resin mediated synthesis of indolizines, pyrrolo [1,2-a] quinolines and isoquinolines: Antibacterial and antifungal evaluation of the products

A number of indolizines and pyrrolo[1,2-a]quinolines/isoquinolines were prepared from phenacyl pyridinium, quinolinium and isoquinolinium salts derived from the reaction of the heterocycles with 2-bromo acetophenone with alkynes and alkenes using amberlite-IRA-402 (OH) ion exchange resin as the base. Antibacterial and antifungal studies were carried out against thirteen bacterial and four fungal strains, which revealed that three derivatives (4a, 4b, 7a) out of fifteen are effective against all the thirteen strains and one derivative, 10, showed dual antibactericidal and antifungal efficacy.

Efficient synthesis of 3,3-diheteroaromatic oxindole analogues and their in vitro evaluation for spermicidal potential

Syntheses of 3,3-diheteroaromatic oxindole derivatives has been achieved by coupling indole-2,3-dione (isatin) with differently substituted indoles and pyrrole in presence of I(2) in i-PrOH. The in vitro spermicidal potentials and the mode of spermicidal action of the synthesized analogues were evaluated and the derivative, 3,3-bis (5-methoxy-1H-indol-3-yl) indolin-2-one (3d) exhibited most significant activity.

Phase transfer catalyzed synthesis of bis-quinolines: antileishmanial activity in experimental visceral leishmaniasis and in vitro antibacterial evaluation.

A one-pot synthesis of some novel bis-quinolines has been achieved under phase transfer catalyzed conditions using 8-hydroxy quinoline derivatives as substrates. The synthesized analogues were evaluated for antileishmanial activity against Leishmania donovani promastigotes and amastigotes. The entire bis-quinolines showed efficacy in both in vitro and in vivo studies. Compound 5 (1,1-bis-[(5-chloro-8-quinolyl)oxy]methane) exhibited the most significant activity. Compounds 4 (1,1-bis-[(8-quinolyl)oxy]methane) and 9 (1,5-bis-[(2-methyl-8-quinolyl)oxy]pentane) also demonstrated significant leishmanicidal efficacy against established visceral leishmaniasis in BALB/c model. Ultrastructural studies of promastigotes treated with compound 5, demonstrated membrane blebbing, chromatin condensation and vacuolization in the parasites and the flagellated parasites became round shaped after treatment. Moreover, in vitro antibacterial activity of compound 5 against several bacterial strains revealed its promising efficacy. The findings suggested that 1,1-bis-[(5-chloro-8-quinolyl)oxy]methane (5) is a bright candidate to be considered as lead compound for leishmanicidal drug.

Synthesis and characterizations of novel quinoline derivatives having mixed ligand activities at the κ and μ receptors: Potential therapeutic efficacy against morphine dependence

Based on an established 3D pharmacophore, a series of quinoline derivatives were synthesized. The opioidergic properties of these compounds were determined by a competitive binding assay using (125)I-Dynorphine, (3)H-DAMGO and (125)I-DADLE for kappa, mu, and delta receptors, respectively. Results showed varying degree of activities of the compounds to kappa and mu opioid receptors with negligible interactions at the delta receptor. The compound, S4 was the most successful in inhibiting the two most prominent quantitative features of naloxone precipitated withdrawal symptoms - stereotyped jumping and body weight loss. Determination of IC(50) of S4 revealed a greater affinity towards mu compared to kappa receptor. In conclusion, quinoline derivatives of S4 like structure offer potential tool for treatment of narcotic addictions.