TMSCl mediated highly efficient one-pot synthesis of octahydroquinazolinone and 1,8-dioxo-octahydroxanthene derivatives

Abstract

A simple, efficient and cost-effective method for the synthesis of octahydroquinazolinone and 1,8-dioxo-octahydroxanthene derivatives by a one-pot cyclocondensation of dimedone and aldehydes, with and without urea or thiourea respectively in the presence of Trimethylsilyl chloride (TMSCl) in MeCN/DMF has been described.

Polystyrene-Supported Pyridinium Chloroaluminate Ionic Liquid as a New Heterogeneous Lewis Acid Catalyst for Knoevenagel Condensation

“…This reaction produces several important key products that include nitriles used in anionic polymerisation and the α,β-unsaturated ester intermediates employed in the synthesis of several therapeutic drugs and pharmacological products. 10,11 Several types of catalysts were introduced previously for Knoevenagel condensation such as the weak bases ammonia, primary amine and secondary amines and their salts, 12,13 16 LaCl 3 , 17 non-cross-linked polystyrene-supported piperazine, 18 zeolite, 19 amino group immobilised on polyacrylamide, 20 SiO 2 -HClO 4 and SiO 2 -PPA, 21 amine functionalised MCM-41, 22 ionic liquids, 23−25 silica based substituted piperidine, 26 and amino functionalised mesoporous silica. 27 However, many of the reported catalysts suffer from drawbacks such as generation of environmentally perilous waste material, tedious work-up, long reaction times, complicated operations, and the use of * Correspondent.…”

Silty Clay-Containing Soil Catalyzed Microwave Assisted Multicomponent Synthesis of Octahydroquinazolinone Derivatives

“…1 Octahydroquinazolinone have been synthesized using aromatic aldehydes, dimedone and urea/thiourea in presence of various catalysts such as montmorillonite, 7 zeolites, 8 boron compounds, 9 Zn(OTf)2, 3 conc. H2SO4, 10 ionic liquids, 11 ion exchange resins, 12 Trimethyl silyl chloride, 13 Nafion-H, 14 VOSO4, 15 conc. HCl, 16 Fe(NO3).9H2O, 17 silica sulfuric acid, 18 t-BuOK, 19 TiO2, 20 ammonium metavanadate, 21 Cu(OTf)2, 22 phosphotungstic acid nanoclusters, 23 BMI.InCl4, 24 SiO2-NaHSO4, 25 ZnO2 nanoparticles, 26 phytic acid, 27 lanthanum oxide, 28 Naion-Ga, 29 CuS QDs, 30 ZrOCl2.8H2O, 31 Cu/SiO2, 32 β-cyclodextrin, aqueous hydrotropic solution of Na-p-Toluene sulfonic acid under microwave irradiation (MW), 33 BF3.SiO2, 34 Aluminate Sulfonic Acid Nanoparticles, 35 Ion exchange resin Nafion 12 H4CuPW11O39, 36 polyvinyl polyvinylpolypyrrolidine supported chlorosulfonic acid, 37 and molybdenum based heterogeneous catalysts (MoO2(acac)2 on zeolite) 38 under MW irradiation.…”

L-Pyrrolidine-2-carboxylic acid sulfate (LPCAS): A new ionic liquid for the synthesis of 1,8-dioxooctahydroxanthenes

“…11 cellulose sulfonic acid. 12 CaCl2, 13 [Et 3 NH][HSO 4 ], 14 SiCl 4 , 15 ceric ammonium nitrate (CAN), 16 Amberlyst-15, 17 nano-TiO2, 18 Fe-Montmorillonite, 19 SmCl 3 , 20 trimethylsilyl chloride, 21 H3PW12O40-MCM-41, 22 [ bmim]HSO 4 , 23 CAN supported on HY-zeolite, 24 [Hbim]BF 4 . 25 These reported methods have various disadvantages and to overcome these problems, we have developed a green protocol for efficient synthesis of 1,8-dioxooctahydroxanthenes using a Brönsted acidic ionic liquid, Lpyrrolidine-2-carboxylic acid sulphate LPCAS) 26 Scheme1).…”