cyclohexa-2,5-diene-1,4-dione

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The sub-title compound was prepared from N-(4-isopropoxyphenyl)aminofumaric acid dimethyl ester (1.57 g, 5.40 mmol), p-benzoquinone (0.60 g, 5.6 mmol) and BF3 etherate (0.83 m L, 5.8 mmol), see procedure in GDR No. 61800 (1967). Yield 1.40 g (71%).

Conditions: temp:4.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 3-(4-diethylaminophenylamino)pent-2-enedioic acid diethyl ester (11.9 g, 34.2 mmol, see step (a) above), 1,4-benzoquinone (4.62 g, 42.8 mmol) and anhydrous MeCN (70 mL) was stirred at 70° C. for 2 d and at 4° C. for 1 d. The solid was collected and recrystallized from MeCN. Yield 4.5 g (30%). The solid was collected recrystallized from MeCN

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Under nitrogen atmosphere, 6 mL of THF was added to 1.22 g (2 mmol, 0.6 equivalent) of (BrZnCH2COOEt.THF)2. Under argon atmosphere, a solution of 0.36 g (3.33 mmol) of p-benzoquinone in 2.5 mL of THF was added dropwise while stirring at 0˜5° C. The mixture was stirred at 20˜25° C. for 1 hour. 5 mL of 1N hydrochloric acid was added dropwise at 20° C. or lower, followed by dilution with 25 mL of ethyl acetate. Then, the layers were separated. The organic layer was washed successively with 5 mL (×2) of 1N hydrochloric acid, 5 mL of water, 5 mL (×2) of an aqueous saturated sodium bicarbonate solution, and 5 mL (×2) of an aqueous saturated sodium chloride solution. After washing, the organic layer was dried with anhydrous magnesium sulfate. After concentration under reduced pressure, purification with silica gel column (developing solvent; ethyl acetate/n-hexane=1/3, 1/2) afforded 0.46 g of the desired product (yield 70%). The mixture was stirred at 20˜25° C. for 1 hour Then, the layers were separated The organic layer was washed successively with 5 mL (×2) of 1N hydrochloric acid, 5 mL of water, 5 mL (×2) of an aqueous saturated sodium bicarbonate solution, and 5 mL (×2) of an aqueous saturated sodium chloride solution After washing the organic layer was dried with anhydrous magnesium sulfate After concentration under reduced pressure, purification with silica gel column (developing solvent; ethyl acetate/n-hexane=1/3, 1/2)

Conditions: temp:100.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 1000 parts of the intermediate from Example 1 was charged to a flask containing 66 parts of p-dimethylaminobenzaldehyde and 14 parts of urea. To this mixture was charged 90 parts of muriatic acid over a 5 minute period. This mixture was allowed to heat up to 95-105° C., and maintained at this temperature overnight. At the end of the hold period, the reaction mixture was allowed to cool to 75° C., and 120 parts of p-benzoquinone was added. The mixture was allowed to stir for 1.5 hrs maintaining a temperature of 75-85° C. The acid is neutralized with a caustic solution, the product washed with water, and dried. A UV/VIS spectrum of the bright mid range blue product shows a lambda max absorbances at 548 nm and 607 nm in toluene. maintained at this temperature overnight to cool to 75° C. maintaining a temperature of 75-85° C the product washed with water dried