Abstract
Objective: In this study, 28 new acetamide derivatives bearing benzoxazole/benzothiazole rings were synthesized and their effects against Alzheimer's disease were tested in vitro.
Material and Method: Amine derivatives (5 and 6) used in the synthesis of final compounds were synthesized by the methylation of commercially available 1,3-benzoxazol-2(3H)-one or 1,3-benzothiazol-2(3H)-one rings with dimethyl sulfate followed by nitration with nitric acid and then reduction with tin chloride. In order to synthesize acetamide derivatives, 5 and 6 was first acylated with bromoacetyl bromide to obtain intermediates 7 and 8. Then, these compounds was reacted with appropriate secondary amines to get the title compounds (9a-n and 10a-n). The structure of the synthesized compounds was elucidated by spectroscopic methods, HRMS and elemental analysis. After the cholinesterase inhibitor activities of all title compounds were determined by the modified Ellman method, their antioxidant activities were measured by the DPPH and ORAC method. Finally, the metal chelator properties of the title compounds were determined.
Result and Discussion: New 2-substituted-N-(3-methyl-2-oxo-2,3-dihydro-1,3-benzoxazol/1,3- benzothiazol-6-yl)acetamide derivative compounds were synthesized. Their cholinesterase inhibitory effects and structure activity relationships were determined. Compound 10g (IC50: 52.90 µM) was identified as the most potent acetylcholinesterase (AChE) inhibitor, and also compound 10h (IC50: 51.03 µM) was determined as the most active derivative for the butyrylcholinesterase (BChE). In the ORAC antioxidant activity test, compounds carrying phenylpiperazine derivatives in their side chains were found to show 3-5 times higher antioxidant activity than the reference trolox. Additionally, the metal chelator activity results of the title compounds showed that the majority of them had metal chelator properties.