Sodium alginate: An efficient biopolymeric catalyst for green synthesis of 2-amino-4H-pyran derivatives

Green and Facile Synthesis of 4H-Pyran Scaffold Catalyzed by Pure Nano-Ordered Periodic Mesoporous Organosilica with Isocyanurate Framework (PMO-ICS)

“…[a] Reaction conditions: Aldehyde ( 2 , 1 mmol), dimedone or 1,3‐cyclohexandione ( 3 a‐b , 1 mmol), malononitrile ( 4 , 1 mmol), EtOH (2 mL, reflux), PMO‐ICS ( 1 , 20 mg). [b] All products are known compounds and their structures were established from their spectral data and melting points as compared with literature values ,,. [c] The yields refer to isolated products.…”

“…Therefore, various catalytic systems using different energy inputs including classical heating, ultrasound irradiation or grinding under ball‐milling conditions have been reported for the synthesis of 4 H ‐pyran derivatives. The most recent examples of homogeneous or heterogeneous catalysts include CaO‐ZrO 2 nanocomposite, silica gel supported polyamine, ceria‐vanadia/silica, egg‐shell under ultrasonic conditions, urea, potassium phthalimide‐ N ‐oxyl, silica‐bonded 5‐n‐propyl‐octahydro‐pyrimido[1, 2‐ a ]azepinium chloride, amino‐appended β‐cyclodextrins, glycerol, DABCO, ammonium formate, tetraethylammonium 2‐(carbamoyl)benzoate under ball milling conditions, [4, 4′‐bipyridine]‐1,1‐diium tricyanomethanide molten salt, N ,2‐dibromo‐6‐chloro‐3,4‐dihydro‐2 H ‐benzo[ e ][1, 2,4]thiadiazine‐7‐sulfonamide 1,1‐dioxide, nanozeolite clinoptilolite, KSF, Amberlyst A21, nano‐sized CoFe 2 O 4 , propane‐1‐sulfonic Acid‐modified magnetic hydroxyapatite, γ‐Fe 2 O 3 , potassium‐exchanged zirconium hydrogenphosphate, heteropolyacids, sodium alginate, KF/Al 2 O 3 , combined NaOAc/KF, Mg/Al hydrotalcite, Mg/Al‐hydrotalcite doped with Sn(IV), ZrCl 4 /[bmim]BF 4 , ionic liquids such as TMG‐[BMIm][X] or [BMIm]BF 4 , (2‐aminomethyl)phenol supported on hydroxyapatite‐encapsulated maghemite nanoparticles, (CTA) 3 [SiW 12 ]‐Li + ‐MMT nanocatalyst, tungstic acid functionalized mesoporous SBA‐15, triazine‐functionalized ordered mesoporous organosilica, Caro's acid silica gel, and silica gel‐supported polyphosphoric acid . However, some drawbacks such as the use of heavy metals, toxic, expensive or odorous catalysts, reagents, and solvents, high catalyst loading, harsh reaction conditions, low yields, long reaction times, and laborious work‐up procedures are associated with many of the reported catalytic systems for the synthesis of 4 H ‐pyran derivatives.…”

Ag3[PMo12O40]: An efficient and green catalyst for the synthesis of highly functionalized pyran‐annulated heterocycles via multicomponent reaction

“…2‐Amino‐5‐oxo‐4‐(thiophen‐2‐yl)‐5,6,7,8‐tetrahydro‐4 H ‐chromene‐3‐carbonitrile ( 4o ): FT‐IR (KBr, ν max , cm −1 ): 3363,3323, 3178, 2956, 2374, 2192, 1679, 1664, 1650, 1608,1409, 1359,1209, 1135, 1000, 709, 626, 536, 501. 1 H NMR (500 MHz, CDCl 3 , δ , ppm): 2.03 (m, 2H), 2.36 (m, 1H), 2.44 (m, 1H), 2.56 (m, 2H), 4.56 (s, 2H, NH), 4.8 (s, 1H), 6.89 (dd, J = 5.1 Hz, J = 1.2 Hz,1H), 6.98 (d, J = 3.2 Hz, 1H), 7.12 (d, J = 5.1 Hz, 1H) 2‐Amino‐3‐ethylacetato‐4‐(phenyl)‐7,7‐ dimethyl‐5‐oxo‐4 H ‐5,6,7,8‐tetrahydrobenzo[ b ]pyran ( 4p ): FT‐IR (KBr, ν max , cm −1 ): 3423, 3265, 3020, 2980, 1667, 1614, 1520, 1462, 1378.…”

Conventional and Microwave‐Assisted Synthesis and Biological Activity Study of Novel Heterocycles Containing Pyran Moiety

“…4 H ‐Pyrans were prepared by different green chemistry methods, which involve using catalysts such as N , N ‐dimethylpyridin‐4‐amine (DMAP) and sodium alginate , or microwave irradiation , and combined microwave and ultrasound irradiation .…”