The multi-component DHPM-yielding Biginelli reaction was first established in 1893 and was ignored for many years until recently. 20 Over the past few years significant efforts have been made to find new procedures to deliver DHPMs in good yields. However, most of the reported procedures end up with low reaction yields. 21 A large number of optimized procedures have been reported where most of the protocols employ various catalytic methods in order to ...
