Coumarin occurs naturally in a variety of plants, such as lentils, sweet sawdust, vanilla grass, and sweet grass. Coumarin has a simple structure, benzopyrone, associated with different reaction centers. Coumarins are further subdivided into different classes: simple coumarins, pyranocoumarins, furanocoumarins, dicoumarins and isocoumarins. Coumarin derivatives are an important class of natural plant metabolites with various biological activities. They can also be synthesized artificially, and various synthetic coumarin derivatives (azoles, sulfonyls, furans, pyrazoles, etc.) have shown good anticancer, antitumor and antiproliferative activities. Coumarin derivatives are not only effective anticancer agents, but also possess minimum side effects. Based on different substitution patterns, these potential active substances show a great ability to modulate potential anticancer activities.
Tetrahydroquinoline is one of the most important simple nitrogen heterocycles, widely found in nature and in a variety of pharmacologically active compounds. Tetrahydroquinoline is an important structure for the synthesis of various biologically active derivatives.