Coumarin is a natural product with aromatic and fragrant characteristics, widespread in the entire plant kingdom. It is found in different plant sources such as vegetables, spices, fruits, and medicinal plants including all parts of the plants—fruits, roots, stems and leaves. Coumarin is found in high concentrations in certain types of cinnamon, which is one of the most frequent sources for human exposure to this substance. However, human exposure to coumarin has not been strictly determined, since there are no systematic measurements of consumption of cinnamon-containing foods. The addition of pure coumarin to foods is not allowed, since large amounts of coumarin can be hepatotoxic. However, according to the new European aroma law, coumarin may be present in foods only naturally or as a flavoring obtained from natural raw materials (as is the case with cinnamon). In this paper, the overview of the current European regulations on coumarin levels in food is presented, along with the most common coumarin food sources, with a special emphasis on cinnamon-containing food. Human exposure to coumarins in food is also reviewed, as well as the methods for determination and separation of coumarin and its derivatives in food.

This mini-review encapsulates the latest findings (past 10 years) in the field of the deep eutectic solvents (DESs) application in the alkylation/arylation of different heterocyclic compounds. These solvents have been developed to fulfill the green chemistry concept demands and have been proven excellent for the application in various fields. This review describes their application in different types of alkylation, C-, N-, O- and S-alkylation. P-alkylation has not yet been published within this scope. Not only have the authors in this study proven that DESs could be successfully applied for this specific type of reaction, but they have also offered an excellent insight into the mechanisms of their action.

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Numerous biological and pharmacological properties of coumarins have designated them as significant synthetic target in many fields. Biscoumarins are considered as an important class of coumarin derivatives that show remarkable pharmacological properties. Therefore, development of the efficient new methods for their synthesis, based on green methodology, would be of a great importance in medicinal and pharmaceutical chemistry. In this work, the ultrasound and microwave assisted synthesis of biscoumarins, starting from corresponding aldehydes and 4-hydroxycoumarin is reported. Molecular iodine was used as an efficient and inexpensive catalyst for a simple synthesis, to obtain excellent yields using ethanol as a solvent. It was found that 10 % (n/n) of molecular iodine catalyzes biscoumarin synthesis in high yields (80–94 %) and in short reaction times, using both ultrasound, as well as microwave promoted conditions. Furthermore, when those two methods are compared, ultrasound promoted reactions were proven to be more suitable for this kind of reaction.