engleski

HIGHLY EFFICIENT MECHANOCHEMICAL SYNTHESIS OF COUMARINYL SEMICARBAZIDES

Green chemistry methods in organic synthesis have been extensively investigated for the purpose to decrease the adverse environmental and human health effects1. Among many, mechanochemical methods have found many different applications in chemistry and chemical engineering. Their pronounced application in the field of organic synthesis is due to the possibility of reducing the reaction time and applying a solvent-free approach2. The combination of mechanical and chemical phenomena enables the reactions with no need for solvent utilization or high temperatures. This work was focused on the synthesis of a series of semicarbazides using coumarinyl hydrazides and different isocyanates as precursors. Solvent-free and catalyst-free approach was shown to be the best approach, yielding desired compounds in short time, excellent purity and high yields. The optimization step showed that the reaction time of 20 min was sufficient for the full consumption of reactants, while the crude product isolation was performed by adding the water to the mixture. Thus, all reactions were performed using the same reaction time, two intervals of 10 min, namely, where the main parameter influencing the isolated product yield was the type and the position of the substituents.

Semicarbazids, Coumarin, Mechanochemistry, Green Chemistry

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