Alzheimer's disease (AD) has been the most significant public source of mortality within the older people across the world. It is one of the most prevalent causes of memory loss and cognitive impairment. It is developed due to a drop in ACh levels that caused damage to cholinergic neurons in the forebrain and hippocampus secondary to an accumulation of oxidative stress mainly ROS and RNS in different brain locations. Existing treatments for this neurodegenerative illness mainly were symptomatic. However, several studies discovered that the quinazoline moiety inhibits the AChE enzyme and scavenges free radicals. To slow the progression of AD, we decided to design and synthesize a new hybrid compound (5) with dual biological functions. Starting with N-methylisatoic anhydride, a series of steps resulted in the final hybrid molecule (5) characterized by LC-MS, 1H NMR, and 13C NMR. The pharmacological effect of compound (5) was assessed using the Elman test. The results of the study showed that compound (5) was co-synthesized (67% yield). Compound (5) anticholinesterase activity showed significant dose-dependent inhibition of the enzyme by compound 5 (IC50 = 11.89 ?g / ml, p <0.05) comparable to the galantamine standard (IC50 = 9.570 ?g / ml). The synthesis quinazoline-antioxidant derivative (5) has significant inhibitory action and might be used as principal compounds in the development of new AD treatments. Key words: Alzheimer's disease, acetylcholine, acetylcholine esterase enzyme, tetrahydroquinazoline, gallic acid, Ellman's assay.