Multicomponent reactions under increased pressure: on the reaction of arylhydrazonals, aromatic aldehydes and malononitrile in Q-Tube

The Q-tube System, A Nonconventional Technology for Green Chemistry Practitioners

“…Very recently, the same research group developed a Qtube assisted procedure to synthesize highly substituted pyridazino [5,4,3-de] [1,6]naphthyridines in moderate to good yields (Scheme 3) [15]. The reactions have been carried out in dioxane at 150 °C in 60 minutes.…”

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].…”

Zn(L-proline)2: An efficient and reusable organocatalyst for the synthesis of polyfunctionally substituted pyrans and 2-amino-4-aryl-8-oxo-4,8-dihydropyrano[3,2-b]pyran derivatives

“…One such protocol involves the use of cheap, recyclable and easy handle catalyst. In continuation of our efforts [21][22][23][24][25][26] aimed at performing reactions under green conditions we reported herein efficient three-component domino reaction for the synthesis of nonannulated 2-amino-4H-pyrans and 2-amino-8-oxo-4,8-dihydro pyrano[3,2-b]pyran derivatives via reaction of aromatic aldehydes, malononitrile and ethyl acetoacetate or kojic acid catalyzed by Zn(L-proline)2 as soft Lewis acid.…”