Reação de Biginelli em Condições Quimicamente Amigáveis e em Paralelo: uma Aula Prática de Síntese Orgânica para os Cursos de Química Medicinal, Química e Farmácia

Resumo

Green chemistry is a goal pursued by synthetic chemists in the development of environmentally friendly
and sustainable protocols. The combination of a multicomponent reaction with parallel synthesis is a very
efficient and green strategy aiming to generate structurally diverse products in a short time. The practical
one-pot multicomponent synthesis of a small library of twelve dihydropyrimidinones (DHPM) using
parallel synthesis is reported here as an undergraduate experiment for the organic synthesis laboratory.
This protocol employed triethyl orthoformate (TEOF) as the promoter of the reaction in solvent-free
conditions and using microwave as an energy source, which is in agreement with green chemistry goals.
The products were isolated through precipitation in water and purified by recrystallization when necessary.
The students also carried out, through a directed study, the structural analysis of their compounds by
melting point determination, infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy.