Ultrasound assisted one-pot synthesis of rosuvastatin based novel azaindole derivatives via coupling-cyclization strategy under Pd/Cu-catalysis: Their evaluation as potential cytotoxic agents.

Addressing the increasing incidences of cancer worldwide along with the multifaceted problem of drug resistance via development of new anticancer agents has become an essential goal. Due to the known cytotoxic effects and reported Akt inhibitory potential of azaindoles we designed a new framework incorporating the structural features of rosuvastatin and 5- or 7-azaindole. The framework was used to construct a library of small molecules for further pharmacological evaluation. The design was supported by the docking studies of two representative molecules in silico. A one-pot sonochemical approach was established for the synthesis of these rosuvastatin based azaindoles that involved the coupling-cyclization of a rosuvastatin derived terminal alkyne with appropriate 3-iodopyridine derivatives under Pd/Cu-catalysis. When tested using an MTT assay, some of the synthesized compounds showed desirable cytotoxic effects against three cancer cell lines e.g. HCT 116, Hep G2 and PA-1 but no significant effects against the non-cancerous HEK cell line. According to the SAR the 5-azaindole ring appeared to be marginally better than the 7-azaindole whereas the activity was varied with the variation of sulfonamide moiety attached to the N-1 atom of the azaindole ring. Among all the groups present in the sulfonamide moiety the p-MeC6H4 group appeared to be most effective in terms of activity. While 3b and 5b were identified as initial hit molecules the compound 5b (in addition to 3b) also showed significant inhibition of Akt1 in vitro that was reflected by its strong interaction with Akt1 in silico (with the docking score -11.7 kcal/mol) involving two H-bonding interactions with Ser7 and Asp439 residues. Further, a reasonable ADME was predicted for 5bin silico. Being a potent inhibitor (MIA Paca-2 IC50 = 18.79 ± 0.17 nM) and with NOAEL (No Observed Adverse Effect Level) > 100 µM in Zebrafish, 5b emerged as a promising compound.

Ultrasound assisted rapid synthesis of mefenamic acid based indole derivatives under ligand free Cu-catalysis: Their pharmacological evaluation.

An improved and rapid synthesis of mefenamic acid based indole derivatives has been achieved via the ligand free Cu-catalyzed coupling-cyclization method under ultrasound irradiation. This simple, straightforward and inexpensive one-pot method involved the reaction of a terminal alkyne derived from mefenamic acid with 2-iodosulfanilides in the presence of CuI and K2CO3 in PEG-400. The reaction proceeded via an initial CC bond formation (the coupling step) followed by CN bond formation (the intramolecular cyclization) to afford the mefenamic acid based indole derivatives in good to acceptable yields. Several of these compounds showed inhibition of PDE4 in vitro and the SAR (Structure Activity Relationship) within the series is discussed. The compound 3d has been identified as a promising and selective inhibitor of PDE4B (IC50 = 1.34 ± 0.46 µM) that showed TNF-α inhibition in vitro (IC50 = 5.81 ± 0.24 µM) and acceptable stability in the rat liver microsomes.