Synthesis, Drug Likeness and In-vitro Screening of Some Novel Quinazolinone Derivatives for Anti-Obesity Activity

Aim: A series of novel quinazolinone derivates was synthesized and assessed for their ability to inhibitory action on pancreatic lipase. The cyclization of quinazolinone-4(3H)-one derivatives was achieved, whereas carbon-carbon cross coupling reactions were carried out on cyclized quinazolinone-4(3H)-one. This synthesis method afforded corresponding 2, 3 and 6 substituted quinazolin-4(3H)-ones (3a to 3m) with moderate to high yields.

Methods: Benzamide derivatives (1a-1b) were synthesized from anthranilic acid using acid-amine reaction, followed by cyclization using catalytic p-toluene sulfonic acid and oxidation using (diacetoxyiodo)benzene to give bromo substituted quinazolin-4(3H)-ones (2a-2b), which were cross coupled to suitable boronic acid using Suzuki-Miyaura condition to obtain desired compound (3a-3m). All synthesized compounds were characterized by FTIR, proton NMR, LC-MS analysis, checked for their drug likeness, absorption and evaluated for in vitro pancreatic lipase inhibition activity.

Results: Analytical interpretation of all compounds with infrared, proton NMR and LC-MS spectroscopy confirmed their correct structure. All compounds (3a-3m) show good absorption and have reasonably good molecular properties except 3c and 3m which violate two criteria for Lipinski’s rule. Whereas, Compounds 3l and 3m showed IC50 value of 13.13±0.84 µg/mL and 13.80±1.27 µg/mL respectively comparable to the Orlistat (12.72±0.97µg/mL), a US FDA approved drug for the treatment of obesity.

Conclusion: Pancreatic lipase is an important lipolytic enzyme, synthesized and secreted through pancreas, plays an important role in dietary trigycerol absorption and metabolism. Therefore, reducing fat absorption through pancreatic lipase inhibition is a promising strategy to treat obesity. Based upon our findings, compounds 3l and 3m can be further developed as potent anti-obesity agents.