diethyl 4-aminobenzene-1,2-dicarboxylate

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: Compound 401 (1.5 g, 5.6 mmol) was dissolved in 280 ml of benzene, and 3.4 g of purified zinc dust was added. Then 10 ml of concentrated hydrochloric acid was added in portions. After 15 min. of stirring at room temperature, another 3.4 g of zinc dust was added and the mixture was stirred at room temperature for 12 hours. 340 ml of cold water was added to the reaction mixture and the mixture was neutralized with 1N NaOH solution. The mixture was transferred to a separatory funnel and the benzene layer was removed. The aqueous layer was extracted with benzene. The combined benzene extracts were washed with water and dried over anhydrous sodium sulfate. After evaporation of the solvent, the pale yellow crude solid was obtained and purified by silica gel column chromatography (n-hexane: acetic acid =8:1) to give 1.1 g (80.6%) of diethyl 4-aminophthalate (compound 402). the mixture was stirred at room temperature for 12 hours The mixture was transferred to a separatory funnel the benzene layer was removed The aqueous layer was extracted with benzene The combined benzene extracts were washed with water dried over anhydrous sodium sulfate After evaporation of the solvent the pale yellow crude solid was obtained purified by silica gel column chromatography (n-hexane: acetic acid =8:1)

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

Procedure: A solution of diethyl 4-aminophthalate (660 mg) in methylene chloride (40 mL) at 0° was treated with pyridine (0.25 mL) and acetyl chloride (0.22 mL). The reaction mixture was allowed to warm to 23° and stirred for 16 h. The reaction mixture was partitioned between saturated aqueous sodium bicarbonate and methylene chloride. The organic layer was washed with water, 2N hydrochloric acid and brine, dried (MgSO4) and evaporated. The residue was dissolved in ethyl acetate, which upon standing afforded the title compound as white crystals (350 mg). M.p. 118°-121°. to warm to 23° The reaction mixture was partitioned between saturated aqueous sodium bicarbonate and methylene chloride The organic layer was washed with water, 2N hydrochloric acid and brine dried (MgSO4) evaporated The residue was dissolved in ethyl acetate