One-pot synthesis of 2-amino-3-cyano-4H-pyrans and pyran-annulated heterocycles using sodium citrate as an organo-salt based catalyst in aqueous ethanol

Abstract

One-pot synthesis of 2-amino-3-cyano-4H-pyrans and pyran-annulated heterocycles using sodium citrate as an organo-salt based catalyst in aqueous ethanol.

One‐pot Multicomponent Synthesis of Novel Chromene Derivatives Using New Organic Phosphate Salt Catalysts

“…[22,23] Recently, chemists have used various catalysts for the elegant synthesis of chromenes due to their unique properties. [24][25][26][27][28][29][30][31][32][33] Reporting the effects of different catalysts such as synthetic copper iodide (CuI), [34] 1,8-diazabicyclo [5.4.0] undec-7ene (DBU), [35] nanoparticles (9Fe 3 O 4 @CÀ SO 3 H), [39] Rochelle salt, [36] iron oxide nanoparticle (Fe 3 O 4 ), [37] tripotassium phosphate (K 3 PO 4 ), [38] dual-organocatalytic (pTsOH.H 2 O & pyrrolidine), [39] ammonium acetate (NH 4 OAc), [40] and sodium citrate [41] in the synthesis of several heterocyclic compounds. Although the developed methods have some advantages, they have several limitations, including low yield, unavailable reagents, effluent pollution, rough reaction conditions, and laborious work-up processes.…”

“…Various subfields of phosphorus‐based organocatalysis have developed rapidly in the past few decades. In the meantime, scientists have introduced phosphorus‐based catalysis as a well‐founded and promising procedure for different C−C, C−H, and C−X bonds [44–49] . Based on our previous interest in assisting the synthesis of new organophosphate salts as an ionic liquid catalyst for MCRs reactions, in this research, the synthesis of three newly organic salt catalysts based on phosphate salts has been reported and its application in the MCRs of chromene compounds has been used [50] .…”

Design, preparation and application of the semicarbazide-pyridoyl-sulfonic acid-based nanocatalyst for the synthesis of pyranopyrazoles

“…Three-component (3-CR) or four-component (4-CR) reactions are often used for the synthesis of pyranopyrazoles 29 . Several methods have been established for their synthesis using copper-immobilized ionic liquid 30 , N -methylmorpholine N -oxide and silver oxide (Ag 2 O) 31 , isonicotinic acid 32 , cetyltrimethylammonium chloride (CTACl) 33 , [bmim]BF 4 34 , choline chloride-urea deep eutectic solvent 35 , bael fruit ash (BFA)-catalyst 36 , P 2 O 5 /SiO 2 or H 3 PO 4 /Al 2 O 3 37 , Nd-salen Schiff base complex immobilized mesoporous silica 38 , uncapped SnO 2 quantum dots (QDs) 39 , sodium citrate 40 , trityl carbocation 41 , CeO 2 /ZrO 2 42 , saccharose 43 , per-6-amino-β-cyclo-dextrin (per-6-ABCD) 44 , 2-carboxy- N , N -diethylethan-aminium acetate 45 , cinchona alkaloid 46 , 4CzIPN/Ni 0 -metallaphotoredox 47 , sodium ascorbate 48 and Meglumine 49 .…”

Three-Component Synthesis of Tetrahydrobenzo[b]pyrans Catalyzed by Sodium Cyclamate

“…Some biologically active tetrahydrobenzo [b]pyrans Due to the importance of these category of heterocycles, many research groups have tried to synthesize them using various catalytic methods. The synthesis of these compounds has been studied by employing catalysts such as L-ascorbic acid, 12 water extract of muskmelon fruit shell ash (WEMFSA), 13 cinchonine, 14 humic acid supported ionic liquid, 15 sodium malonate, 16 sodium citrate, 17 N,Ndimethylbenzylamine (DMBA), 18 potassium phthalimide, 19 potassium hydrogen phthalate, 20 1-ethyl-3methylimidazolium 2-hydroxybenzoate, 21 L-pyrrolidine-2-carboxylic acid sulfate, 22 1,3dihexylimidazolium 2-aminobenzoate, 23 choline taurinate, 24 artificial sweetener ionic liquid, 25 triethanolamine, 26 1-methyl-3-(2-phenoxyethyl)-1H-imidazol-3-ium hydroxide, 27 choline chloridepentaerythritol, 28 1-ethyl-3-methylimidazolium acetate, 29 bovine serum albumin and NaCl (ball milling method), 30 lipase from Thermomyces lanuginosus immobilized on particle silica gel (TLIM), 31 trishydroxymethylaminomethane, 32 ammonium carbonate, 33 MgSO4, 34 K2CO3/montmorillonite, 35 and free-ZnO nanoparticles. 36 Electrolysis using LiClO4 37 or deep eutectic solvent, 38 catalyst-free using UV365 light, 39 magnetized water, 40 aqueous ethylene glycol at 100 °C41 as well as aqueous PEG-400 42 are among approaches for the synthesis of tetrahydrobenzo [b]pyrans.…”

“…For the yield and reaction time to be improved, the catalyst loading was increased. When 10 mol% of an organo-catalyst was used, the product (4a) was achieved in 35% isolated yield for 3 h ( 17). The reaction was also examined under the catalyst-free conditions refluxing water.…”