NEW DISCOVERIES IN THE KNOEVENAGEL SYNTHESIS OF 5-ALKYLIDENE MELDRUM'S ACIDS

摘要

Five known 5-aIkylidene Meldrum's acids were synthesized using a room temperature Knoevenagel condensation method previously reported in the literature by increasing the starting material concentration by a factor of five. The series consisted of several products derived from heteroaromatic aldehydes and cyclic ketones, some of which had previously not been synthesized using the lower concentrations in our previously published method. The corresponding products were characterized via ~1H and ~(13)C NMR studies. The yield of the reaction performed compared well with reported literature yields that were obtained from more tedious methods, as well as the Knoevenagel condensation method published previously. The results from these experiments have provided some insight into the complexities of the reaction with cyclic ketones.