: Alzheimer's is a neurodegenerative pathology. The first therapeutic strategy for treating AD was mainly acetylcholinesterase inhibitors (AChEIs). One of them is Tacrine, a linear tricyclic compound that occupies an important place in treating this disease with its pharmacophore properties. In this regard, the development of tacrine-analogs more efficient and safe with new measures and investigations has drawn immense attention. Various structural modifications of Tacrine have been carried out on different parts. Mainly some change in the ring structure of Tacrine or by connecting the amino group with different hybrids based on natural or synthetic compounds and drugs already in existence. These tacrine congeners have considerable potential for developing new drugs for the treatment of Alzheimer's disease. Therefore, this review presents an overview of the essential structural modifications in tacrine rings based on the current trends reported in recent decades towards using natural products and synthetic analogs as a source of new anti-Alzheimer drugs.

2-aminopyridines scaffolds are an important class of nitrogen heterocyclic compounds with a wide range of biological activities. Multicomponent reactions (MCRs) are useful methods for the construction of nitrogen heterocyclic compounds. In this context, syntheses of 2-aminopyridines derivatives via MCRs have attracted considerable attention in recent years. We present, in this work, a rapid and efficient synthesis of 2-aminopyridine derivatives, via the catalyst-free four-component method. This protocol provides a simple and practical approach to functionalized 2-aminopyridnes from readily available substrates under solvent-free conditions.

The specific synthesis of N-alkylated pyridone has attracted considerable attention due to the presence of these units in a wide range are components, both in natural products and in many active pharmaceuticals [1]. Generally, the synthesis of N-alkyl-2-pyridones is feasible by the alkylation of 2-pyridones. In this case, selectively witching the reaction is required to induce the Nor O-alkylation. In this communication, we present our results of the synthesis of different Nsubstituted 2-pyridone using multicomponent reactions (MCRs) methods under microwave radiation conditions.