Catalyst‐ and Solvent‐Free Synthesis of N‐Acylhydrazones via Solid‐State Melt Reaction

Abstract

We describe a fast, simple, and effective synthesis of N-acylhydrazones via a solid-state melt reaction under catalyst-and solvent-free conditions. The reactions of 2-furoic hydrazide, 2-thiophenecarboxylic acid hydrazide and substituted alkyl/aryl-acylhydrazides with aromatic aldehydes proceeded well at 120 °C in only 30 min to give the corresponding products in good to excellent isolated yields (74-100%) without purification using column chromatography. Gram scale experiments also worked well. This method could be considered as a green procedure, which has a high atom economy (94.69-94.90%), high reaction mass efficiency (84.27-87.33%), low E-factor (0.15-0.19 g/g), and low process mass intensity (13.21-14.30 g/g).

Eutectic Media Open a Synthetic Route to Oligocitrazinic Acid Fluorophores of Purple Hue

“…This is because collisions between the reactants are much more frequent and give higher reaction rates, which often results in high purity of the products with high selectivity. [35,[37][38][39] Reaction kinetics, monitored over time by UV-vis absorption spectroscopy (Figure 1, right), show a similar trend. The band at 340 nm (associated with CzA) develops initially but decreases over time in favour of an increasing band intensities at 520 and 560 nm.…”

“…Solvent‐free reactions are known to offer remarkable advantage, when compared to solution reactions because of the change in reaction kinetics. This is because collisions between the reactants are much more frequent and give higher reaction rates, which often results in high purity of the products with high selectivity [35,37–39] …”