One‐pot synthesis of polyfunctionalized pyrans catalyzed by basic ionic liquid in aqueous media

Abstract

in Wiley InterScience (www.interscience.wiley.com).An efficient and convenient method for the synthesis of polyfunctionalized 4H-pyrans has been achieved through the one-pot condensation of aromatic aldehydes, malononitrile, and 4-hydroxycoumarin, phenols or active methylene carbonyl compounds such as 1, 3-cyclohexanedione and dimedone in the presence of 1-butyl-3-methyl imidazolium hydroxide ([bmim]OH) as catalyst in aqueous media. This method offers several advantages short reaction time, high yields, and simple procedure.

An Improved Procedure for the Three-Component Synthesis of 1H-Pyrazolo[1,2-B]Phthalazine-5,10-Dione Derivatives Using Basic Ionic Liquid

“…The reaction was carried out in six different solvents and at different temperatures and the results are shown in Table 1. Ethanol gave the best yield (entry 8) and after evaluating various temperatures (entries [6][7][8][9][10][11], 60 °C was found to be optimal. We also investigated the effect of lowering and raising the mol% of the catalyst.…”

Efficient tandem synthesis of a variety of pyran-annulated heterocycles, 3,4-disubstituted isoxazol-5(4H)-ones, and α,β-unsaturated nitriles catalyzed by potassium hydrogen phthalate in water

“…Several synthetic methods have been widely applied for synthesis of pyran-based heterocyclic compounds, using many homogeneous or heterogeneous organic, inorganic, and nanomaterial catalysts, for example hexamethylenetetramine (HMT) [40], heteropolyacid [41], diammonium hydrogen phosphate [42], DBU [43], piperidine [44][45][46][47], tetrabutylammonium bromide (TBAB) [48], ionic liquids [49], morpholine [50], 4-(dimethylamino)pyridine (DMAP) [51], urea [52], 3-hydroxypropanaminium acetate (HPAA) [53], N-propylpiperazine sodium n-propionate (SBPPSP) [54], silica gel [55], sulfonic acid-functionalized silica [ [60], meglumine [61], I 2 /K 2 CO 3 [62], cetyltrimethylammonium bromide (CTABr) [63], nano-sized MgO [64], nano-structured Na 2 CaP 2 O 7 [65], NaHCO 3 [66], Na 2 CO 3 [67], triazine-functionalized ordered mesoporous organosilica [68], potassium phosphate tribasic trihydrate [69], Mg/Al hydrotalcite [70], Amberlyst A21 [71], DABCO [72], CeO 2 /CaO nanocomposite oxide [73], triton B [74], tetrabutylammonium chloride (TBAC) [75], nano-eggshell powder [76], basic alumina [77], [bmim]OH [78,79], LiBr [80], glycine [81], silica nanoparticles [82], ionic liquid choline chlorid...…”

Preparation of neutral ionic liquid [2-Eim] OAc with dual catalytic-solvent system roles for the synthesis of 2-amino-3-cyano-7-hydroxy-4-(aryl)-4H-chromene derivatives

“…Other properties such as laser dyes and fluorescence [30], pigments and cosmetics [31], are well known for decades. There have already been several references related to the synthesis of 4H-chromene derivatives using various catalysts are also reported [50][51][52][53][54]. However, there are still many problems in these reported catalysis methods, such as the use of expensive reagents, catalyst activation difficulty, long reaction time, low selectivity, environmental hazards, acidic or basic conditions and catalyst recycling problem.…”