Biginelli vs Hantzsch esters study under infrared radiation and solventless conditions

Abstract

In this work, we report the results obtained during the condensation of various benzaldehydes with ethyl acetoacetate and urea or thiourea, in the presence of a bentonitic clay as catalyst. These reactions were performed under solventless conditions with infrared radiation as the energy source. Both Biginelli and Hantzsch esters were synthesized, with the Biginelli compounds being the main products. Finally, the obtained compounds were characterized by comparison of the corresponding melting points with those reported in the literature, together with the EIMS data and the elemental composition obtained by high resolution MS.