To design a synthetic pathway for a new drug candidate targeting acetylcholinesterase AChE enzyme, we can start by modifying an existing AChE inhibitor, such as donepezil, to improve its potency, selectivity, and safety profile. The following synthetic pathway is proposed:1. Starting with 5,6-dimethoxy-2-aminopyridine 1 , perform a nucleophilic aromatic substitution reaction with 3-chloropropylamine hydrochloride 2 in the presence of potassium carbonate K2CO3 as a base in dimethylformamide DMF solvent. This will yield N- 3-aminopropyl -5,6-dimethoxy-2-pyridinamine 3 .2. Next, perform a reductive amination reaction between compound 3 and 4- 4-fluorophenyl piperidin-4-one 4 using sodium triacetoxyborohydride NaBH OAc 3 as a reducing agent in a mixture of acetic acid and methanol. This will yield N- 3- 5,6-dimethoxy-2-pyridinyl propyl -4- 4-fluorophenyl piperidine 5 .3. To improve selectivity and reduce toxicity, introduce a hydrophilic group to the molecule. Perform a selective O-demethylation of compound 5 using boron tribromide BBr3 in dichloromethane DCM to yield 5-hydroxy-6-methoxy-N- 3- 4- 4-fluorophenyl piperidin-4-yl propyl pyridin-2-amine 6 .4. Finally, to further improve potency and selectivity, perform a Suzuki-Miyaura cross-coupling reaction between compound 6 and an appropriate boronic acid derivative 7 in the presence of a palladium catalyst Pd PPh3 4 and a base K2CO3 in a mixture of water and an organic solvent e.g., toluene . This will yield the final drug candidate 8 .This synthetic route is designed to be cost-effective and scalable for large-scale production. The use of readily available starting materials, mild reaction conditions, and well-established synthetic methods should facilitate the development of a potent, selective, and safe AChE inhibitor for the treatment of Alzheimer's disease. Further optimization of the synthetic route and the drug candidate structure can be performed based on experimental results and structure-activity relationship studies.