ethyl 1,4-dihydroxynaphthalene-2-carboxylate

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

Procedure: 23 g of compound (6) prepared above was suspended in 300 ml of chloroform and, while keeping the solution at 5°-10° C., 27.4 g of sulfuryl chloride was slowly dropwise added thereto. After reacting for 1.5 hours, water was added to the reaction solution to conduct separation and extraction. The organic phase was dried with anhydrous sodium sulfate, and chloroform was distilled off under reduced pressure. Rapid purification of the residue through silica gel column chromatography gave compound (7) as crystals. Yield: 8.8 g (33%). at 5°-10° C. separation and extraction The organic phase was dried with anhydrous sodium sulfate, and chloroform was distilled off under reduced pressure Rapid purification of the residue through silica gel column chromatography

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

Procedure: 23 g of compound (6) prepared above was suspended in 300 ml of chloroform and, while keeping the solution at 5°-10° C., 27.4 g of sulfuryl chloride was slowly dropwise added thereto. After reacting for 1.5 hours, water was added to the reaction solution to conduct separation and extraction. The organic phase was dried with anhydrous sodium sulfate, and chloroform was distilled off under reduced pressure. Rapid purification of the residue through silica gel column chromatography gave compound (7) as crystals. Yield: 8.8 g (33%). at 5°-10° C. separation and extraction The organic phase was dried with anhydrous sodium sulfate, and chloroform was distilled off under reduced pressure Rapid purification of the residue through silica gel column chromatography

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

Procedure: 28 g of 2-phenoxycarbonyl-1,4-dihydroxynaphthalene was dissolved in ethanol under a nitrogen stream, and 20.4 g of sodium ethylate was added thereto, followed by refluxing for 5 hours under heating. After being cooled, the solution was made weakly acidic with acetic acid, then ethanol was distilled off. Ethyl acetate and water were added thereto to separate and extract the product. The product was purified through silica gel column chromatography with an element having the same composition as that used in the Synthesis Example 1 to obtain compound (6) as crytals. Yield: 13 g (56%). was added by refluxing for 5 hours under heating After being cooled ethanol was distilled off Ethyl acetate and water were added to separate extract the product The product was purified through silica gel column chromatography with an element that used in the Synthesis Example 1

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

Procedure: 23 g of compound (6) prepared above was suspended in 300 ml of chloroform and, while keeping the solution at 5°-10° C., 27.4 g of sulfuryl chloride was slowly dropwise added thereto. After reacting for 1.5 hours, water was added to the reaction solution to conduct separation and extraction. The organic phase was dried with anhydrous sodium sulfate, and chloroform was distilled off under reduced pressure. Rapid purification of the residue through silica gel column chromatography gave compound (7) as crystals. Yield: 8.8 g (33%). at 5°-10° C. separation and extraction The organic phase was dried with anhydrous sodium sulfate, and chloroform was distilled off under reduced pressure Rapid purification of the residue through silica gel column chromatography

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

Procedure: 28 g of 2-phenoxycarbonyl-1,4-dihydroxynaphthalene was dissolved in ethanol under a nitrogen stream, and 20.4 g of sodium ethylate was added thereto, followed by refluxing for 5 hours under heating. After being cooled, the solution was made weakly acidic with acetic acid, then ethanol was distilled off. Ethyl acetate and water were added thereto to separate and extract the product. The product was purified through silica gel column chromatography with an element having the same composition as that used in the Synthesis Example 1 to obtain compound (6) as crytals. Yield: 13 g (56%). was added by refluxing for 5 hours under heating After being cooled ethanol was distilled off Ethyl acetate and water were added to separate extract the product The product was purified through silica gel column chromatography with an element that used in the Synthesis Example 1