Preparation, Characterization, and Catalytic Application of a Nanosized Ce1MgxZr1-xO2Solid Heterogeneous Catalyst for the Synthesis of Tetrahydrobenzo[b]pyran Derivatives

Butane‐1‐sulfonic acid immobilized on magnetic Fe3O4@SiO2 nanoparticles: A novel and heterogeneous catalyst for the one‐pot synthesis of barbituric acid and pyrano[2,3‐d] pyrimidine derivatives in aqueous media

“…Arylidene barbituric acids, as important heterocyclic compounds, can be obtained via the Knoevenagel condensation reaction between barbituric acid and its derivatives with aldehydes or ketones that do not contain α‐hydrogen. For this purpose, a variety of catalysts and reagents have been used to facilitate this reaction including CuO nanoparticles, BiCl 3 , [DABCO](SO 3 H) 2 Cl 2 , Ce 1 Mg x Zr 1 − x O 2 , ZnO, CoFe 2 O 4 , SiO 2 ⋅12WO 3 ⋅24H 2 O, NH 2 SO 3 H and K 2 NiP 2 O 7 …”

Knoevenagel‐Michael‐cyclocondensation Tandem Reaction of Malononitrile, Various Aldehydes and Dimedone Catalyzed by Sulfonic Acid Functionalized Pyridinium Chloride as a New Ionic Liquid and Catalyst

“…[16][17][18][19][20][21][22][23][24][25] The synthesis of tetrahydrobenzo[b]pyran derivatives is important due to their significant anti-coagulant, diuretic, spasmolytic, anti-cancer, and anti-anaphylactic properties. 28,29 Several methods have been introduced for the preparation of tetrahydro-4H-benzopyran derivatives. 27 Additionally, substituted 4H-pyrans are observed as units in the structure of some natural products.…”

An Environmentally Benign Protocol for Aqueous Synthesis of Tetrahydrobenzo[b]Pyrans Catalyzed by Cost-Effective Ionic Liquid

“…Hence, considering the fascinating advantages of MCRs, some methodologies for the synthesis of tetrahedrondydro[ b ]pyrans via three components one-pot reactions catalyzed by 1,4-diazabicyclo[2.2.2]octane [14], N -methylimidazole [15], tetra-methyl ammonium hydroxide [16], (NH 4 ) 2 HPO 4 [17] K 3 PO 4 [18], ZnO-beta zeolite [19], nanosized Ce 1 MgXZr 1− x O 2 [20], Ru(II) complex [21], Na 2 SeO 4 [22], S -proline [23], l -proline [24], 1,8-diazabicyclo[5.4.0]undec-7-ene [25], sulfonic acid functionalized silica [26], phenylboronic acid [27], caro’s acid-silica gel [28], and cerium(III) chloride [29] have been reported. In addition, procedures of catalyst-free and 2,2,2-trifluoroethanol as reaction medium [30], microwave and ultrasonic irradiation [9,31,32] could also give satisfactory yields of pyrans.…”