A Novel and Simple Experimental Procedure for Synthesizing, Purifying, and Identifying Coumarin in Undergraduate Heterocyclic Chemistry Laboratories (Journal Article)

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Abstract: Heterocyclic compounds are an integral part of research, particularly in the pharmaceutical field. The synthesis of such compounds in an undergraduate laboratory can help students understand the relevance and importance of their field of study. Our experimental activity introduces a novel procedure to synthesize coumarin, a heterocyclic formed by two fused rings, using commercial reagents and equipment found in most undergraduate teaching laboratories. What sets our proposed procedure apart is its short reaction time (15 min), high yields (80–85%), and avoidance of extreme experimental conditions, making it highly suitable for implementation in heterocyclic chemistry laboratories at the undergraduate level. The reaction mechanism is straightforward and easily comprehensible to students. Additionally, the fluorescence properties of coumarin are utilized to visually inspect the reaction’s progress and the corresponding purification procedure, enhancing the experiment’s pedagogical value and piquing the student’s curiosity. We successfully implemented this experimental proposal in three different groups, involving approximately 90 students, and received enthusiastic feedback. The heterocyclic compound obtained in the laboratory was highly engaging for the students, as it allowed them to apply the theoretical knowledge gained in their classes to practical experiments. They had the opportunity to explore the reactivities of the functional groups and witness the formation of a compound of great biological importance. The synthesis of heterocycles with notable biological applications serves as an exciting activity for the students. The fluorescent properties of the formed coumarin not only identify the product by visual inspection but also allow them to delve into the concept of fluorescence.