3.4- Dioxobutanoic acid

Aryl-2,4-dioxobutanoic acids (67) upon treatment with IBD afford the corresponding furans 70. The first step of the reaction is the formation of coupling products 68, which then expel CO2 to give diketo acids 69. The loss of water from the tautomer of 69 gives cyclized products, enolic lactones 70 (72MI1) (Scheme 22). 

C6H9NO4 2,3-Dioxobutanoic acid 2-oxime ethyl ester Extraction-photometric Pd, Ru 3... 

Dihydroxynaphthalene with 4-phenyl-2,4-dioxobutanoic acid upon addition to phosphorus oxychloride gave after reaction during 20 hours at ambient temperature,... 

Dioxobutanoic acid Me ester, in D-00986 Fumaric acid Mono-Me ester, in F-00038... 

In a 500 mL Erlenmeyer flask, 1,4-cyclohexanedione (1.12 g) and anhydrous sodium acetate (22 g) were dissolved in glacial acetic acid (60 mL), and the mixture was heated to 115 °C. Benzyl 2,3-dioxobutanoate-2-phenylhydrazone (5.92 g) was mixed with 20 g of zinc dust, and was added slowly to the stirred mixture keeping the temperature between 120-130 °C. Once the addition was complete, the solution was stirred at 100 °C for 30 min. The solution was cooled to 80 °C and poured into 700 mL of ice water with stirring. The residual zinc was washed several times with hot acetic acid and combined with the ice water. The precipitate was filtered and recrystallized from ethanol to give 34... 

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