Molecular sieves: an efficient and reusable catalyst for multi-component synthesis of dihydropyrano[2,3-C]pyrazole derivatives

An Efficient One‐Pot Five‐Component Tandem Sequential Approach for the Synthesis of Pyranopyrazole Derivatives via Suzuki Coupling and Multicomponent Reaction

“…The resultss howed that the best yield was obtained at 80 8Ci nt he presence of 1.0 mol %o fp alladium ( Table 1, entry 7). Furthermore, the reactions were carried out at different temperatures ranging from 40-100 8C( Ta ble1,e ntries [17][18][19]. It is clear that the yield increased with the increasing temperature, and the optimal temperature was 80 8C.…”

“…Recently,afour-component reaction( 4CR) fort he synthesis of pyranopyrazoles from ethylacetoacetate, aldehyde, malononitrile, and hydrazine hydrate has been developed. Triethylamine, [16] Amberlyst A21, [17] cetyltrimethylammoniumc hloride (CTACl), [18] molecular sieves, [19] magnetic Fe 3 O 4 nanoparticles, [20] SnO 2 quantum dots, [21] and organocatalysts such as lproline, [22] glycine, [23] meglumine, [24] per-6-amino-b-cyclodextrin, [25] as well as lipase [26] were found to be extremely efficient catalysts for synthesis of as eries of dihydropyranopyrazoles via a4 CR.…”

Recent Advance in Development of 3-Methyl-4-Arylmethylene Isoxazole-5(4h)-Ones and 6-Amino-1,4-Dihydropyrano[2,3-C]-Pyrazole-5-Carbonitriles: Synthetic Applications and Pathways

“…[62] Guo and co-workers have utilized meglumine as a biodegradable and highly efficient and reusable catalyst for the one-pot, four-component synthesis of ethyl acetoacetate, hydrazine hydrate, various aldehydes and malononitrile in aqueous ethanol at the room temperature to afford products in excellent yields (Scheme 31). [63] A wide range of catalysts, such as irradiation, which was demonstrated by Gujar and co-workers (Scheme 32) [64] . The authors have also demonstrated various aluminates and silicate based catalysts to promote this transformation.…”

The Effect of Molecular Sieves on the Thermolysis of Cedar in a Tubular Furnace Reactor

“…Dehydration and de-carboxylation can be promoted by the use of pro-zeolite catalysts at atmospheric pressure [29], [30]. Molecular sieves are reported as effective cracking catalysts along with other zeolites [31]. These zeolite are an attractive low-cost substitute for traditional catalysts used in high pressure hydrogenation biomass thermolysis [29], [32], [33].…”