Multi Component Reactions under Increased Pressure: On the Mechanism of Formation of Pyridazino[5,4,3-de][1,6]naphthyridine Derivatives by the Reaction of Malononitrile, Aldehydes and 2-Oxoglyoxalarylhydrazones in Q-Tubes

Abstract

Efficient synthesis of phenanthridin-6(5H)-one derivatives 12a–n in a four-component reaction of aldehyde hydrazone, aromatic aldehydes and malononitrile in Q-Tubes is reported. The results showed that the methodology has the advantage of being a one-pot synthesis of tricyclic systems in good yields. Potential routes leading to formation of compounds 12 are discussed. The structures of the synthesized compounds could be unequivocally established via X-ray crystal structure determination and spectroscopic methods.

Glycerol and Q-Tubes: Green Catalyst and Technique for Synthesis of Polyfunctionally Substituted Heteroaromatics and Anilines

“…There is now a boom in the use of high pressure in science [50], and reactions under high pressure and/or temperature proved to behave in a different manner than those under normal thermal conditions [51,52]. The newly invented borosilicate tubes known as Q-tubes have allowed the performance of difficult or otherwise impossible chemical reactions in chemical laboratories [53,54,55,56]. Shifts in transition state along a reaction coordinate, a switch of the rate-determining step, and the possible transformation of a transition state into a stable minimum, are among the possible phenomena that can occur for reactions under pressure, especially in fluids [57].…”