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We report herein the synthesis, α-glucosidase inhibition and docking studies for a series of 3-15 new flavones. A simple nucleophilic substitution reaction takes place between 3'hydroxyflavone (2) with halides to afford the new flavones. Chalcone (1), 3'hydroxyflavone (2) and the newly synthesized flavones (3-15) were being evaluated for their ability to inhibit activity of α-glucosidase. Compounds 2, 3, 5, 7-10 and 13 showed good inhibitory activity with IC50 values ranging between 1.26 and 36.44 μM as compared to acarbose (IC50 = 38.25 ± 0.12 μM). Compounds 5 (5.45 ± 0.08 μM), 7 (1.26 ± 0.01 μM) and 8 (8.66 ± 0.08 μM) showed excellent inhibitory activity, and this may be due to trifluoromethyl substitution that is common for these compounds. Compound 7, a 2,5-trifluoromethyl-substituted compound, recorded the highest inhibition activity, and it is thirty times better than the standard drug. Docking studies for compound 7 suggest that both trifluoromethyl substituents are well positioned in a binding pocket surrounded by Phe300, Phe177, Phe157, Ala278, Asp68, Tyr71 and Asp214. The ability of compound 7 to interact with Tyr71 and Phe177 is extremely significant as they are found to be important for substrates recognition by α-glucosidase.

2,4-Dimethylbenzoylhydrazones 1-30 were synthesized by condensation reactions of 2,4-dimethylbenzoylhydrazide with various aromatic aldehydes and characterized. The assigned structures of compounds 10, 15 and 22 were further supported by single-crystal X-ray diffraction data. The synthesized compounds were evaluated for their in vitro DPPH radical scavenging activity. They exerted varying degree of scavenging activity toward DPPH radical with IC 50 values between 25.6-190 µM. Compounds 1, 4, 2, 3, 7, and 6 have IC 50 values of 25.6, 28.1, 29.3, 29.8, 30.0 and 30.1 µM respectively, showing better activity than an n-propyl gallate standard (IC 50 value = 30.30 µM). For super oxide anion scavenging activity compounds 1, 2 and 3 with IC 50 values of 98.3, 102.6, and 105.6, respectively, also showed better activity than the n-propyl gallate standard (IC 50 value = 106.34 µM).

Schiff bases of 3,4-dimethoxybenzenamine 1 – 25 were synthesized and evaluated for their antioxidant activity. All the synthesized compounds were characterized by various spectroscopic techniques. In addition, the characterizations of compounds 13 , 15 and 16 were supported by crystal X-ray determinations and their geometrical parameters were compared with theoretical DFT calculations at the B3LYP level of theory. Furthermore, the X-ray crystal data of two non-crystalline compounds 8 and 18 were theoretically calculated and compared with the practical values of compounds 13 , 15 , 16 and found a good agreement. The compounds showed good DPPH scavenging activity ranging from 10.12 to 84.34 μM where compounds 1 – 4 and 6 showed stronger activity than the standard n -propyl gallate. For the superoxide anion radical assay, compounds 1 – 3 showed better activity than the standard.