Synthesis, anti-inflammatory and analgesic evaluation of thioxoquinazolinone derivatives

A series of 3-substituted-2-thioxoquinazolin-4(3H)-one derivatives have been synthesized and their structures have been elucidated on the basis of IR, (1)H-NMR, elemental analysis and mass spectroscopic studies. Anti-inflammatory and analgesic activity of the synthesized compounds was evaluated by Carrageenan induced rat paw edema method and Eddy's hot plate method respectively. Among the synthesized compounds N-(4-hydroxyphenyl)-N-(4-oxo-3-phenyl-2-thioxo-3,4-dihydroquinazolin-1(2H)methyl)acetamide (PTQ01) showed excellent anti-inflammatory activity. N-(4-ethoxyphenyl)-N-(3-(naphthalen-2yl)-4-oxo-2-thioxo-3,4-dihydroquinazolin-1(2H)-yl)methyl)acetamide (NTQ02), N-(4-Hydroxyphenyl)-N-((3-naphthalen-2-yl)-4-oxo-2-thioxo-3,4-dihydorquinazolin-1(2H)-ylmethyl)acetamide (NTQ01), N-((3-(4-ethoxyphenyl)-4-oxo-2-thioxo-3,4-dihydoquinazolin-1(2H)-yl)methyl)-N-(4-hydroxyphenyl)acetamide (ETQ01) N-(3-(4-ethoxyphenyl)-4-oxo-2thioxo-3,4-dihydroquinazolin-1(2H)-ylmethyl)-N-(4-hydroxyphenyl)acetamide (ETQ04), N-(4-ethoxyphenyl)-N-((4-oxo-3-phenyl-2-thioxo-3,4-dihydoquinazolin-1(2H)-yl)methyl)acetamide (PTQ02) and N-(4-ethoxyphenyl)-N-(3-(4-ethoxyphenyl)-4-oxo-2-thioxo-3,4-dihydoquinazolin-1(2H)-yl)methyl)acetamide (ETQ02) at a dose of 20 mg/kg exhibited significant anti-inflammatory activity compared to that of standard drug diclofenac sodium. The compound 2-(2,3-dimethylphenyl)(3-(4-ethoxyphenyl)-4-oxo-2-thioxo-3,4-dihydroquinazolin-1-2H)-1ylmethylamino)benzoic acid PTQ03 and sodium 2-(2-((2,6-dichlrophenyl)(3-(4-oxo-2-thioxo-3,4-dihydroquinazolin-1(2H)-yl)methyl)amino)phenylacetate (PTQ04) showed moderate anti-inflammatory activity. The compounds PTQ01, PTQ02, PTQ04, ETQ01 and ETQ02 showed significant analgesic activity compared with that of standard drug pentazocin.