Synthesis, Analgesic and Anti-inflammatory Activities of 3-Ethyl-2-substituted Amino-3H-quinazolin-4-ones

Purpose: To synthesize a series of novel 3-ethyl-2-substituted amino-quinazolin-4(3H)-ones and evaluate them for their analgesic and anti-inflammatory activities. Methods: The compounds, 3-ethyl-2-substituted amino-quinazolin-4(3H)-ones, were synthesized by reacting the amino group of 3-ethyl-2-hydrazino quinazolin-4(3H)-one with a variety of aldehydes and ketones. The synthesized compounds were characterized by Fourier transform infrared (FTIR), protonnuclear magnetic resonance spectroscopy (^1H-NMR) and mass spectrometry. The purity of the compounds was determined by elemental analysis. Test for analgesic activity was performed by tail-flick technique using Wistar albino mice while anti-inflammatory activity was evaluated by carrageenan-induced paw oedema test in rats. Diclofenac sodium was used as positive control for both analgesic and anti-inflammatory activities. Results: The compound, 3-ethyl-2-(cyclohexylidene-hydrazino)-3H-quinazolin-4-one (AS1), emerged as the active analgesic (activity, 63.89 %) and anti-inflammatory (activity, 60.00 %) compound of the series, and compared well with the reference standard, diclofenac sodium, which exbited analgesic and anti-inflammatory activities of 62.04 and 65.11 %, respectively Conclusion: The compound (AS1) can serve as a lead molecule for further development to a clinically useful novel class of analgesic and anti-inflammatory agents.