Green and cost effective protocol for the synthesis of 1,8-dioxo-octahydroxanthenes and 1,8-dioxo-decahydroacridines by using sawdust sulphonic acid

Dendrons containing boric acid and 1,3,5-tris(2-hydroxyethyl)isocyanurate covalently attached to silica-coated magnetite for the expeditious synthesis of Hantzsch esters

“… Entry Catalyst Product Catalyst Loading (mg) Solvent T °C Time (min.) Yield Ref 1 KH 2 PO 4 5a 5 mol% EtOH/H 2 O 120 5 h 94 146 2 DABCO–PEG-400 ionic liquid 5a 80 – 115 12–14 h 92 148 3 Silica bonded N -propyl sulfamic acid 5a 30 EtOH Reflux 2 h 86 149 4 Sawdust sulphonic acid 5a 50 EtOH Reflux 1 h 90 100 5 Fe 3 O 4 @SiO 2 @PTS-THEIC-(CH 2 ) 3 OB(OH) 2 5a 10 EtOH Reflux 1 h 92 This Work 6 L-proline 7a 10 …”

“…Thus, MCRs are usually a good alternative for the sequential multistep synthesis, especially for useful heterocyclic scaffolds such as Hantzsch esters including 1,4-dihydropyridines (DHPs), PHQs and PHAs in organic synthesis and medicinal chemistry 91 – 96 . Generally known as one of the main groups of nitrogen heterocycles, polyhydroquinolines (PHQs) and polyhydroacridines (PHAs) have become considerably interesting due to their significant therapeutic and pharmacological properties 97 – 100 . Indeed, they are used as antimalaria, calcium β-blocker, antioxidant, antimicrobial, antifungal, vasodilator, anticancer, bronchodilator, antiatherosclerotic, geroprotective, hepatoprotective and antidiabetic agents as well as in the production of laser colors, radical reservoirs and safe hydrogen transfer agents 4 , 101 – 111 .…”

An expedient and straightforward solvent‐free synthesis of 1,8‐dioxo‐octahydroxanthenes using eco‐friendly aluminized polyborate catalyst

“…[ 10 ] They are also extensively used as photodynamic sensitizers [ 11 ] and also acts as corrosion inhibitors. [ 12 ]…”

“…In general, the straightforward synthesis of 1,8‐dioxooctahydroxanthene involves one‐pot domino Knoevenagel‐Michael reaction of 2 moles of dimedone with 1 mole of aromatic aldehydes. In literature several catalytic systems are reported for their synthesis such as [DDPA][HSO 4 ], [ 22 ] Ni NPs@ N ‐doped titania, [ 23 ] C/TiO 2 ‐SO 3 H, [ 24 ] ZnO, [ 25 ] sulfated zirconia, [ 26 ] Fe 3 O 4 @SiO 2 Imid‐PMA, [ 27 ] β‐cyclodextrin, [ 28 ] Bronsted acidic ionic liquids, [ 29 ] Fe‐Cr‐Ni alloy nano‐belts, [ 30 ] ZnO‐NPs, [ 31 ] alumina‐sulfuric acid, [ 32 ] MSrGO NCs, [ 33 ] Choline chloride, [ 34 ] SmCl 3 , [ 35 ] PDNES, [ 36 ] PVPP‐BF 3 , [ 37 ] PSA, [ 38 ] natural phosphate, [ 39 ] n‐TSA, [ 40 ] Fe 2 (SO 4 ) 3 .7H 2 O, [ 41 ] barium perchlorate, [ 42 ] Ag@CDNS‐N/PMelamine, [ 43 ] sawdust sulphonic acid, [ 12 ] nano‐WO 3 ‐supported sulfonic acid, [ 44 ] CoNP@SBA‐15, [ 45 ] PFPA, [ 46 ] MnFe 2 O 4 , [ 47 ] Fe 3 O 4 @PS@His[HSO 4 − ], [ 48 ] FSM‐16/AEPC‐SO 3 H [ 49 ] and zeolite nanoparticles. [ 50 ]…”

A novel and efficient magnetic nanocatalyst functionalized with 1,3,5-tris(2-hydroxyethyl)isocyanurate and boric acid for the synthesis of symmetric and asymmetric Hantzsch esters

“…They enjoy potential biological and pharmacological uses. [6] they are used as anti-malaria, antimicrobial, antifungal, vasodilator, anticancer, bronchodilator, antiatherosclerotic, antitumor, geroprotective, hepatoprotective, antidiabetic activity, anti-cancer, and anti-tumor agents, and as calcium b-blockers, also in the producing of laser color. [7][8][9] In an attempt to indicate how applying MNPs would impact the process, this study reports uses of boric acid functionalized MNPs (1) as a novel catalyst in the one pot synthesis of polyhydroquinolines and polyhydroacridines derivatives.…”