Efficient Synthesis of Novel Biginelli and Hantzsch Products Sourced from Biorenewable Furfurals Using Gluconic Acid Aqueous Solution as the Green Organocatalyst.

The Biginelli reaction provides 3,4-dihydropyrimidin-2(1)-ones (DHPMs), whereas the Hantzsch reaction leads to 1,4-dihydropyridines (DHPs) by the one-pot, multicomponent, and operationally simple transformations starting from readily available starting materials. DHPMs and DHPs are well-established heterocyclic moieties in the synthetic organic chemistry literature and have pronounced pharmacological activities. This work reports the synthesis of novel DHPMs and DHPs from carbohydrate-derived 5-substituted-2-furaldehydes by employing gluconic acid aqueous solution (GAAS) as an efficient, inexpensive, and eco-friendly catalyst.