Green Protocol for the Novel Synthesis of Thiochromeno[4,3-b]pyridine and Chromeno[4,3-b]pyridine Derivatives Utilizing a High-Pressure System

Abstract

A suitable and effective Q-tube-assisted strategy for the synthesis of novel, unrivalled thiochromeno[4,3- b ]pyridine and chromeno[4,3- b ]pyridine derivatives has been sophisticated, which includes ammonium acetate-mediated cyclocondensation reactions between 3-oxo-2-arylhydrazonopropanals and heterobenzocyclic ketones such as thiochroman-4-one and chroman-4-one, respectively. The high-pressure Q-tube reactor was shown to be superior to conventional heating. Furthermore, this Q-tube reactor-assisted protocol is safe owing to facile pressing and sealing, a broad substrate scope, and simple work-up and purification processes, as well as being scalable and having a high atom economy. The proposed mechanistic route includes two sequential dehydrative stages. In this investigation, X-ray crystallographic analysis was performed to authenticate the targeted products.

High-Pressure Metal-Free Catalyzed One-Pot Two-Component Synthetic Approach for New 5-Arylazopyrazolo[3,4-b]Pyridine Derivatives

“…To achieve this target, a diversity of 3-oxo-arylhydrazonals 2a – v was prepared and introduced in order to evaluate their reactions with 5-amino-2-phenyl-4 H -pyrazol-3-one ( 1 ) under the specified optimal conditions ( Table 1 , entry 12). In general, the electronic properties of the aryl motifs attached to 3-oxo-arylhydrazonals ( 2 ) had a minimal influence on reaction efficacy [ 28 , 29 ]. The reaction was exceptionally adaptable to both electron-releasing motifs as well as the electron-accepting motifs.…”

The Q-Tube-Assisted Green Sustainable Synthesis of Fused Azines: New Synthetic Opportunities via Innovative Green Technology

“…Bearing in mind all of the above and inspired by our previous work utilizing green chemistry tools for the synthesis of biologically active heterocyclic compounds [17][18][19][20] and the recently published work on utilizing the high-pressure Q-tube [21][22][23][24][25], we are boiling point is exceeded during the reaction process. The Arrhenius equation states that reaction rates double when the temperature is raised by 10 °C (Equation (1)).…”

“…Bearing in mind all of the above and inspired by our previous work utilizing green chemistry tools for the synthesis of biologically active heterocyclic compounds [17][18][19][20] and the recently published work on utilizing the high-pressure Q-tube [21][22][23][24][25], we are On the other hand, for a plethora of organic reactions, layered double hydroxides [LDHs] can serve as catalysts [12][13][14][15]. The hydroxyl groups in Mg(OH) 2 [brucite] coordinate octahedrally with some Mg 2+ cations, similar to that in brucite, whereas some Al 3+ ions are substituted with trivalent ions.…”

“…Bearing in mind all of the above and inspired by our previous work utilizing green chemistry tools for the synthesis of biologically active heterocyclic compounds [17][18][19][20] and the recently published work on utilizing the high-pressure Q-tube [21][22][23][24][25], we are encouraged to highlight and confirm the success of the Q-tube system in organic synthesis as economic tools that save energy. In this study, we tested the Q-tube for the reaction of chalcones with nitrogen nucleophils.…”

Synthesis of 5H-chromeno[3,4-c]pyridine derivatives through ruthenium-catalyzed [2 + 2 + 2] cycloaddition

“…6 Recent protocols of the synthesis of chromeno[4,3- b ]pyridines involving cyclocondensations under high pressure conditions were also reported. 7 However, the reported strategies for accessing the regioisomer skeleton 5 H -chromeno[3,4- c ]pyridine are more scarce. An example of functionalized 5 H -chromeno[3,4- c ]pyridine was synthesized from flavan-4-ones by a Vilsmeier–Haack/malononitrile addition sequence.…”