(1,4-dioxonaphthalen-2-yl) acetate

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

Procedure: 2-acetyloxynaphthalene-1,4-dione (1.24 g) and 3-trifluoromethylbutanoic acid (1.08 g) were reacted using the method as descibed in Example 3 yielding the title compound (353 mg) (mp 168° C.). This compound is listed as compound 11 in the Tables below.

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

Procedure: The method of Example 1 was followed using 2-acetyloxynaphthalene-1,4-dione (1.24 g, 5.74 mmol) and 2-methylpentanoic acid (1.00 g) yielded the title compound (608 mg) after hydrolysis in. 30 ml THF using potassium hydroxide (5×exess) in water (8 ml) (mp 82-83° C.). This compound is listed as compound 3 in the Tables below.

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

Procedure: 595 g (5.89 moles) of triethylamine are added dropwise in 30 minutes to a suspension of 500 g (2.87 moles) of 2-hydroxy-1,4-naphthoquinone (lawsone) in 2200 ml of ethyl acetate, cooled to +5° C., maintaining the temperature below +10° C. At the end of the dripping a dark red solution is obtained. The solution is kept at +5-10° C. for 30 minutes. 550 g (5.39 moles) of acetic anhydride are added dropwise in 30 minutes, maintaining the temperature between +5 and +10° C. At the end of the dripping, the mixture is left under agitation at +5° C. for 4 hours. The solid is filtered and washed with a mixture of 250 ml of ethyl acetate and 250 ml of hexane pre-cooled to +5° C. The damp product is dried at +40° C. at reduced pressure for 6 hours providing 496 g (yield 80%) of 2-acetoxy-1,4-naphthoquinone (acetyl-lawsone) as a yellow solid with melting point −131°-134° C. cooled to +5° C. maintaining the temperature below +10° C At the end of the dripping a dark red solution is obtained maintaining the temperature between +5 and +10° C At the end of the dripping, the mixture is left under agitation at +5° C. for 4 hours The solid is filtered washed with a mixture of 250 ml of ethyl acetate and 250 ml of hexane pre-cooled to +5° C The damp product is dried at +40° C. at reduced pressure for 6 hours