One‐pot Synthesis of 2‐Amino‐4H‐chromenes Derivatives in Aqueous Solution of Choline Hydroxide

Abstract

2‐Amino‐4H‐chromenes have showed broad bioactivities and attracted great attention in synthetic chemistry. Here, the aqueous solution of choline hydroxide was found to be an efficient catalytic system for the one‐pot synthesis of 2‐amino‐4H‐chromenes under room temperature. Various aldehydes, malononitrile and phenols could be converted to the corresponding 2‐amino‐4H‐chromenes smoothly with good to excellent isolated yields. This catalytic system had high chemo‐selectivity with biocompatible catalyst in green solvents, water. Its operation and work‐up procedures were very simple, and importantly, the target compounds could be obtained from simple centrifugation and washing procedures, no column purification was needed. In addition, the catalytic system involving choline hydroxide and water could be easily reused for at least five cycles with high activity. The above advantages made this catalytic system promising in the industrial production of 2‐amino‐4H‐chromenes.

Synthesis of Silica Particles with Controlled Microstructure via the Choline Hydroxide Cocatalyzed Stöber Method

“…This unique organic nature and biocapacity make ChOH a promising candidate for a variety of biological and biochemical applications. 17,18 In addition, the reducing ability of ChOH due to the presence of hydroxyl groups, a feature not shared by other reported catalysts, allows certain precursors to be reduced internally within the silica particles, thereby eliminating the need for additional reducing agents. Therefore, the integration of ChOH as a cocatalyst in the Stober method for the synthesis of silica particles presents an innovative approach, especially for the potential application of hollow silica particles in various fields such as catalysis, sensing, and drug delivery.…”

“…Choline cation plays a critical role in essential biochemical processes due to its involvement as a fundamental component in compounds, such as acetylcholine and phosphatidylcholine. This unique organic nature and biocapacity make ChOH a promising candidate for a variety of biological and biochemical applications. , In addition, the reducing ability of ChOH due to the presence of hydroxyl groups, a feature not shared by other reported catalysts, allows certain precursors to be reduced internally within the silica particles, thereby eliminating the need for additional reducing agents. Therefore, the integration of ChOH as a cocatalyst in the Stöber method for the synthesis of silica particles presents an innovative approach, especially for the potential application of hollow silica particles in various fields such as catalysis, sensing, and drug delivery. − Despite the classical synthesis methods, such as hard templating and soft templating, we can synthesize hollow silica particles using a template-free method, taking advantage of ChOH to rationally regulate the microstructure of the silica particles. − …”

[Ch][TAPSO] As an Efficient Ionic Liquid Catalyst for One‐Pot Synthesis ofTetrahydro‐4H‐chromenes and 3,4‐Dihydropyrano[c]chromenes

“…[21][22][23] Therefore, the synthesis of tetrahydro-4H-chromenes and 3,4-dihydropyrano[c]chromenes compounds have received considerable interest among the researchers. A number of synthetic methods for tetrahydro-4H-chromenes have been developed so far employing metal catalyst, [24,25] organocatalyst, [26][27][28][29][30] immobilized heterogenous catalyst, [31] magnetic nanocatalyst, [32][33][34][35][36] ionic liquids, [37] and nanostructured molten salt [38] etc. The synthesis of 3,4-dihydropyrano[c] chromene derivatives have also been reported by using various catalysts such as organocatalyst, [39] magnetic nanocatalyst, [40,41] ionic liquids, [42,43] and metal catalyst.…”

Synthesis of α,β-Unsaturated Ketones in Water: The Claisen–Schmidt Condensation Revisited

“…This green synthetic methodology was employed to synthesize 15 structurally different derivatives with good yields . Ionic liquids are also useful for the long-term storage of proteins , and nucleic acids. − Among these choline-based ILs, choline hydroxide (ChOH) has demonstrated exceptional capabilities as a base catalyst. − Moreover, it is highly soluble in water. Hence, one can carry out several organic syntheses in water while using ChOH as a catalyst, which makes the development of sustainable synthesis strategies feasible .…”