Reactions of Alkylidene Aminomethylenemalonates

The treatment of isopropylidene phenylaminomethylenemalonate with 85% sulfuric acid at ambient temperature for 14 hr gave phenylaminometh-ylenemalonic acid in 42% yield (81CB3471). 

Isopropylidene (l-aminoalkylidene)malonates (454) were heated under reflux in ethanol in the presence of sodium ethylate overnight. After evaporation of the solvent, the residues were treated with water to give 3-aminoacrylates (1608) in 48-89% yields. If the residues were treated with water and 10% hydrochloric acid, 3-oxo esters (1609) were obtained in 22-81% yields. When isopropylidene (l-aminoalkylidene)malonates (454) were heated under reflux in concentrated hydrochloric acid, methylke-tones (1610) were prepared in 24-73% yields (81S130). 

Isopropylidene amino(ethoxycarbonylmethyl)methylenemalonate (1611) and boron trifluoride etherate were heated under reflux in ethanol for 48 hr. When the reaction mixture was treated with aqueous potassium carbonate, the triester (1612) was obtained in 40% yield, while after evaporation of the solvent and treatment of the residue with water, diethyl 3-oxoglutarate was isolated in 22% yield (8IS 130). 

Isopropylidene N-substituted aminomethylenemalonates (442, R1 = R2 = Me) were methylated with methyl iodide in dimethyl sulfoxide in the presence of sodium hydride at room temperature overnight to give the N-methyl derivatives (1615) in 56-90% yields [88JCS(P )863,88JCS(P2)759]. 

Alkylidene phenylaminomethylenemalonates (444) were reacted with sodium hydride or lithium hydride in acetonitrile at 40°C for 2 hr. The reaction mixtures were then cooled to 0-20°C, and they were treated with a solution of dialkyl peroxydicarbonate in methylene chloride for 24 hr to give 5-alkoxycarbonyloxy-5-phenyliminomethyl-1,3-dioxane-4,6-diones (1616) in 54-75% yields (80CB2630). 

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