Some Condensation Reactions of Isopropylidene Malonate¹

Synthesis of Dialkyl {(aryl)[2,2-Dimethyl-4-oxo-6-(Piperidin-1-yl)-4H-[1,3]Dioxin-5-yl]Methyl}Phosphonate by Reaction of Meldrum's Acid, Aryl Aldehydes and Trialkyl Phosphites in the Presence of Piperidine

“…Compound 1 was prepared as previously described in the literature. 10 Synthesis of compounds 5a-e; general procedure A mixture of trialkyl phosphite (2 mmol) at room temperature over 2 min was added dropwise to a magnetically stirred solution of Meldrum's acid (2 mmol) and aryl aldehydes (2 mmol) in dichloromethane (15 mL). The reaction mixture was then stirred for 1 minute.…”

Ionic Liquid–Mediated Knoevenagel Condensation of Meldrum's Acid and Aldehydes

“…[11] Hedge and colleagues have reported such reactions without any catalyst at room temperature in highly polar solvents such as dimethyl sulfoxide (DMSO) and dimethyl formamide (DMF), which are known to be highly toxic and teratogenic and are suspected carcinogens. [12] In recent years, ionic liquids have attracted considerable interest as a green reaction media because of their fascinating properties such as negligible vapor pressure, ability to solvate a wide range of both organic and inorganic substrates, highly polar yet noncoordinating nature, and immiscibility with a number of organic solvents, as well as (in some cases) water. [13] Further, they are also regarded as designer solvents because their properties, such as hydrophilicity/hydrophobicity, polarity, acidity/basicity, viscosity, and recyclability, can be tuned by proper selection of cation and anion.…”

Ultrasound Promoted Synthesis of 3‐Carboxycoumarins in Aqueous Media

“…In this reaction, excess of Meldrum's acid should be avoided because it may react with 3-carboxycoumarins leading to a decrease of yield and purity. 19 To investigate the reaction we first examined the solvent effect on the reaction. The data (Table 1) show that the reaction is favored in water, although it involves the elimination of a molecule of water.…”