Synthesis, characterization, antioxidant, antidiabetic, anticholinergic, and antiepileptic properties of novel N‐substituted tetrahydropyrimidines based on phenylthiourea

In the presence of trifluoroacetic acid, on the basis of three‐component condensation of phenylthiourea with its salicylaldehyde and methyl‐3‐oxobutanoate, an efficient method for the synthesis of 1‐(4‐(2‐hydroxyphenyl)‐6‐methyl‐1‐phenyl‐2‐thioxo‐1,2,3,4‐tetrahydropyrimidin‐5‐yl)ethanone (I) has been worked out. These novel N‐substituted tetrahydropyrimidines based on phenylthiourea showed good inhibitory action against acetylcholinesterase (AChE), α‐glycosidase, and human carbonic anhydrase (hCA) isoforms I and II. K i values of AChE enzyme were in the range of 0.48 to 7.46 nM. The hCA I and II were effectively inhibited by the compounds, with K i values in the range of 502.44 to 923.11 nM for hCA I and 400.32 to 801.57 nM for hCA II, respectively. The antioxidant activity of the novel N‐substituted tetrahydropyrimidines based on phenylthiourea was investigated by using different in vitro antioxidant assays; including 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH·) radical scavenging, Cu 2+  and Fe 3+ reducing activities.