Phthalimide as a versatile pharmacophore scaffold: Unlocking its diverse biological activities

An Efficient Synthesis of 1-(1,3-Dioxoisoindolin-2-yl)-3-aryl Urea Analogs as Anticancer and Antioxidant Agents: An Insight into Experimental and In Silico Studies

The present investigation reports the efficient multistep synthesis of 1-(1,3-dioxoisoindolin-2-yl)-3-aryl urea analogs (7a-f) in good yields. All the 1-(1,3-dioxoisoindolin-2-yl)-3-aryl urea analogs (7a-f) were characterized by spectroscopic techniques. Five among the six compounds were tested against 56 cancer cell lines at 10 µM as per the standard protocol. 1-(4-Bromophenyl)-3-(1,3-dioxoisoindolin-2-yl)urea (7c) exhibited moderate but significant anticancer activity against EKVX, CAKI-1, UACC-62, MCF7, LOX IMVI, and ACHN with percentage growth inhibitions (PGIs) of 75.46, 78.52, 80.81, 83.48, 84.52, and 89.61, respectively. Compound 7c was found to exhibit better anticancer activity than thalidomide against non-small cell lung, CNS, melanoma, renal, prostate, and breast cancer cell lines. It was also found to exhibit superior anticancer activity against melanoma cancer compared to imatinib. Among the tested compounds, the 4-bromosubstitution (7c) on the phenyl ring demonstrated good anticancer activity. Docking scores ranging from -6.363 to -7.565 kcal/mol were observed in the docking studies against the molecular target EGFR. The ligand 7c displayed an efficient binding against the EGFR with a docking score of -7.558 kcal/mol and displayed an H-bond interaction with Lys745 and the carbonyl functional group. Compound 7c demonstrated a moderate inhibition of EGFR with an IC50 of 42.91 ± 0.80 nM, in comparison to erlotinib (IC50 = 26.85 ± 0.72 nM), the standard drug. The antioxidant potential was also calculated for the compounds (7a-f), which exhibited good to low activity. 1-(2-Methoxyphenyl)-3-(1,3-dioxoisoindolin-2-yl)urea (7f) and 1-(4-Methoxyphenyl)-3-(1,3-dioxoisoindolin-2-yl)urea (7d) demonstrated significant antioxidant activity with IC50 values of 15.99 ± 0.10 and 16.05 ± 0.15 µM, respectively. The 2- and 4-methoxysubstitutions on the N-phenyl ring showed good antioxidant activity among the series of compounds (7a-f). An in silico ADMET prediction studies showed the compounds' adherence to Lipinski's rule of five: they were free from toxicities, including mutagenicity, cytotoxicity, and immunotoxicity, but not for hepatotoxicity. The toxicity prediction demonstrated LD50 values between 1000 and 5000 mg/Kg, putting the compounds either in class IV or class V toxicity classes. Our findings might create opportunities for more advancements in cancer therapeutics.

Direct synthesis of phthalimides via palladium-catalysed double carbonylation of o-dihaloarenes with nitroarenes

The direct carbonylation of readily available nitro compounds is more attractive and straightforward than the use of traditional amines as nucleophiles. Herein, a practical palladium-catalysed double carbonylation of nitroarenes with o-dihaloarenes has been developed for the construction of various N-aryl phthalimides. Key to the success of this transformation is the use of Mo(CO)6, which acts as both a reducing agent and a solid carbonyl source. A wide range of nitroarenes and o-dihaloarenes as well as o-iodobenzoic acids reacted smoothly to give phthalimides in 27-94% yields.