Synthesis and Biological Evaluation of New N-(4-Substituted phenyl)glycine Derivatives as Potential Anti-inflammatory Agents

Background: Designing new anti-inflammatory agents possessing safe therapeutic profiles and devoid of potential undesirable side effects is an active field in medicinal chemistry. Thus, a series of N-(4-substituted phenyl)glycine derivatives was designed and synthesized. The idea behind the design is to utilize the bifunctionality of 4-aminoacetophenone via converting the amino group into glycine derivative as a side arm to mimic the glycine amino acid enhancing the overall physicochemical and biological characteristics. In addition, the opposite acetyl group was used as a center for modification and derivatization. Methods: The starting N-(4-acetylphenyl)glycine was converted into two intermediates: the chalcone analog 2 and the thiosemicarbazone derivative 8. Both 2 and 8 were derivatized and/or cyclized into different heterocyclic target derivatives (3-7 and 9-12). The target compounds were screened for anti-inflammatory activity using carrageenan-induced rat paw edema assay. Results: The results showed that compounds 6, 7, and 3, were the most active among the tested compounds at 50 mg/kg dose level with % inhibition of edema of 51.82, 43.80, and 40.39, respectively. Conclusion: The authors succeeded to introduce a simple and versatile skeleton with a side arm resembling the glycine amino acid; imparting a potential improvement in physicochemical properties. We utilize the other side of the skeleton’s aromatic ring as a center for derivatization. The chalcone analog and its cyclized heterocyclic derivatives were of remarkably higher anti-inflammatory activity than the thiosemicarbazone and its derivatives.