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.
Oxirane is a three-membered ring compound consisting of one oxygen atom and two carbon atoms. Oxirane is present in natural products such as cryptocin, which has anticancer properties, and azidomycin, trienone, and epoxidomycin, which have shown activity against drug-resistant leukemias and AIDS-related lymphomas. Other oxirane containing bioactive molecules have anti-inflammatory, immunosuppressive, and antitumor activities. Oxiranes are a strained ring susceptible to various nucleophilic, ring-opening or rearrangement reactions, so they are considered to be one of the most important intermediates in organic synthesis.