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One-Pot Synthesis of 4H-Pyrano[3,2-c]coumarin Derivatives Catalyzed by Deep Eutectic Solvent

“…Based on the control experiments and known reactions in the literature, [46][47][48][49] a possible mechanism for the synthesis of the pyrano[3,2-c] coumarin derivatives is proposed (Scheme 4). First, in the presence of the zinc chloride/acetamide DES, a Knoevenagel reaction between benzaldehyde (2a) and ethyl cyanoacetate (3a) produces intermediate product 3a′.…”

Recent advances in metal-free heteroatom-doped carbon heterogonous catalysts

“…We are interested in novel heterogeneous catalysis, trying to design, prepare, and use them in our contemplated reactions in our laboratory, which delightfully have been mostly successful. [53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68] Following, the same interest we have collected and reviewed the most recent activities on the applications of different organic transformations being performed effectively under heterogeneous catalysis. [69][70][71][72][73][74][75] In this review, we will mainly focus on the latest developments (2015 onwards) of heteroatom-doped carbon materials (single-element B-, N-, S-, and P-doped, dual-elements doped, and triple-elements doped carbons) as promising metal-free heterogeneous catalysts, including the catalysts preparation methods with an emphasis on their application in various organic transformations (oxidation, hydrogenation, hydrochlorination, dehydrogenation, coupling, etc.…”

Hydroxyapatite‐Supported Polyoxometalates for the Highly Selective Aerobic Oxidation of 5‐Hydroxymethylfurfural or Glucose to 2,5‐Diformylfuran under Atmospheric Pressure

“…[2] Among different POMs, molybdovanadophosphate with Keggin structure was commonly used as a strong Brønsted acid type catalyst in biomass conversions. [3][4][5] Many efforts had been made to solidify their structures into heterogeneous forms, which were exhaustively reviewed by Ishii and co-workers. [6] One solidifying is to partially exchange protons of molybdovanadophosphate with Cs + , Ag + , Lewis metal ions such as Sn 4 + , Zn 2 + , or anionic organo-groups of anion, ionic liquid, and quaternary ammonium.…”

“…Strong acidic or redox catalysts like polyoxometalates (POMs) or heteropolyacids (HPAs), were considered as essential candidates for various biomass conversions [2] . Among different POMs, molybdovanadophosphate with Keggin structure was commonly used as a strong Brønsted acid type catalyst in biomass conversions [3–5] . Many efforts had been made to solidify their structures into heterogeneous forms, which were exhaustively reviewed by Ishii and co‐workers [6] .…”