反应详情

温度

5 °C

Preparation A: A solution of 1,2-dibutoxy-1-cyclobutene-3,4-dione (6.09, 0.027 mole) in 40 mL of tetrahydrofuran was cooled to 5° C. in an ice-water bath and treated dropwise over a period of 9 minutes with a solution of 1.8 mL of concentrated ammonium hydroxide in a mixture of 8 mL of tetrahydrofuran and 1 mL of methanol. After stirring at 5° C. for 30 minutes and at ambient temperature for 90 minutes the mixture was concentrated under reduced pressure to a slurry. A small amount of Skellysolve B was added and the product was collected by filtration after 16 hours of standing at 0° C. to give 3.26 g of the title compound. A sample (8.54 g) was partly dissolved in acetone, filtered and cooled to give 4.51 g of purified title compound; mp=165.5°-168° C. (clear melt).

1. concentrationwas concentrated under reduced pressure to a slurry
2. additionA small amount of Skellysolve B was added
3. filtrationthe product was collected by filtration after 16 hours
4. customof standing at 0° C.