naphthalene-1,4-diol

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

Procedure: Among the pyrrole derivatives of 1,4-dihydroxynaphthalene which can be used according to the present invention, 2-(1-methyl-1H-pyrrol-2-yl)-[1,4]-dihydroxynaphthalene and methyl [5-(1,4-dihydroxynaphthalen-2-yl)-1-methyl-1H-pyrrol-2-yl]acetate are more particularly preferred.

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

Procedure: Using the same procedure, napthalene- 1,4-diol and 1,4-dihydroxy-2-methyl-naphthalene were oxidized to obtain a 93% yield of 1,4-naphthoquinone and a 97% yield of 2-methyl-1,4-naphthoquinone, respectively.

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

Procedure: Using the same procedure, napthalene- 1,4-diol and 1,4-dihydroxy-2-methyl-naphthalene were oxidized to obtain a 93% yield of 1,4-naphthoquinone and a 97% yield of 2-methyl-1,4-naphthoquinone, respectively.

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

Procedure: The peroxygenase oxidised naphthalene yielding multiple products 1-naphthol, 2-naphthol, 1,4-naphthoquinone, naphthalene-1,4-diol and some unidentified products.

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

Procedure: The peroxygenase oxidised naphthalene yielding multiple products 1-naphthol, 2-naphthol, 1,4-naphthoquinone, naphthalene-1,4-diol and some unidentified products.

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 112 g of naphthohydroquinone and 560 ml of n-decanol were placed in a 1 l three-necked flask and 56 ml of concentrated sulfuric acid was dropwisely added thereto for 30 minutes under nitrogen gas stream while stirring. Thereafter, the mixture was further stirred for 30 minutes and, then, heated at 50° C. for 1 hour and 30 minutes. After cooling, ethyl acetate-water was added to the reaction mixture and the precipitated crystals were filtered off. An aqueous sodium hydroxide solution was added to the filtrate so as to water layer reach pH of 5 to 6. Then, the ethyl acetate layer was washed with water and dried with MgSO4 overnight. The dried ethyl acetate solution was evaporated under reduced pressure to remove ethyl acetate and n-decanol. The residue was dissolved in 1 l of ethyl acetate and treated with 26 g of active carbon followed by concentration under reduced pressure. The residue was recrystallized from a mixed solvent of ethyl acetate and n-hexane and, further, recrystallized from benzene to obtain 73 g of white crystals having a melting point of 89° to 90° C. Thereafter, the mixture was further stirred for 30 minutes After cooling the precipitated crystals were filtered off An aqueous sodium hydroxide solution was added to the filtrate so as to water layer Then, the ethyl acetate layer was washed with water dried with MgSO4 overnight The dried ethyl acetate solution was evaporated under reduced pressure to remove ethyl acetate and n-decanol The residue was dissolved in 1 l of ethyl acetate treated with 26 g of active carbon followed by concentration under reduced pressure The residue was recrystallized from a mixed solvent of ethyl acetate and n-hexane further, recrystallized from benzene

Conditions: temp:60.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 160 g of naphthohydroquinone and 416 g of cyclohexanol were placed in a 1 l three-necked flask, and 80 ml of concentrated sulfuric acid was dropwisely added thereto for 10 minutes under nitrogen gas stream while stirring. Thereafter, the reaction mixture was heated at 60° C. for 40 minutes and then cooled to room temperature. The reaction mixture was extracted with 500 ml of ethyl acetate. The ethyl acetate layer was washed with water until the washing reached neutral and, then, dried with MgSO4 overnight. The dried ethyl acetate solution was concentrated under reduced pressure. The residue was distilled under reduced pressure to obtain 140 g of oily substance. The oily substance was dissolved in ethyl acetate and treated with about 20 g of active carbon followed by concentration under reduced pressure. The residue was recrystallized from benzene two times to obtain 60 g of white crystals having a melting point of 120° to 121° C. cooled to room temperature The reaction mixture was extracted with 500 ml of ethyl acetate The ethyl acetate layer was washed with water until the washing dried with MgSO4 overnight The dried ethyl acetate solution was concentrated under reduced pressure The residue was distilled under reduced pressure to obtain 140 g of oily substance treated with about 20 g of active carbon followed by concentration under reduced pressure The residue was recrystallized from benzene two times

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 216 g of naphthohydroquinone and 527 g of n-octyl alcohol were placed in a 2 l three-necked flask, and 114 ml of concentrated sulfuric acid was dropwisely added thereto for 30 minutes under nitrogen gas stream while stirring. Thereafter, the reaction mixture was heated at 50° C. for 1 hour and then cooled to room temperature. The reaction mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with ammonia-water until the washing reached pH of 5 to 6. The ethyl acetate layer was further washed two times with an aqueous sodium chloride solution and, then, dried with anhydrous sodium sulfate. The dried ethyl acetate solution was concentrated under reduced pressure to precipitate crystals. The crystals were filtered off, and the filtrate was further concentrated under reduced pressure to distill off ethyl acetate and n-octyl alcohol to obtain oily substance. The oily substance was purified by column chromatography using a mixed solvent of n-hexane and ethyl acetate and, then, recrystallized from n-hexane to obtain 190 g of white crystals having a melting point of 73° to 74° C. cooled to room temperature The reaction mixture was extracted with ethyl acetate The ethyl acetate layer was washed with ammonia-water until the washing The ethyl acetate layer was further washed two times with an aqueous sodium chloride solution dried with anhydrous sodium sulfate The dried ethyl acetate solution was concentrated under reduced pressure to precipitate crystals The crystals were filtered off the filtrate was further concentrated under reduced pressure to distill off ethyl acetate and n-octyl alcohol to obtain oily substance The oily substance was purified by column chromatography recrystallized from n-hexane

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

Procedure: Among the pyrrole derivatives of 1,4-dihydroxynaphthalene which can be used according to the present invention, 2-(1-methyl-1H-pyrrol-2-yl)-[1,4]-dihydroxynaphthalene and methyl [5-(1,4-dihydroxynaphthalen-2-yl)-1-methyl-1H-pyrrol-2-yl]acetate are more particularly preferred.

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

Procedure: Among the pyrrole derivatives of 1,4-dihydroxynaphthalene which can be used according to the present invention, 2-(1-methyl-1H-pyrrol-2-yl)-[1,4]-dihydroxynaphthalene and methyl [5-(1,4-dihydroxynaphthalen-2-yl)-1-methyl-1H-pyrrol-2-yl]acetate are more particularly preferred.

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

Procedure: Using the same procedure, napthalene- 1,4-diol and 1,4-dihydroxy-2-methyl-naphthalene were oxidized to obtain a 93% yield of 1,4-naphthoquinone and a 97% yield of 2-methyl-1,4-naphthoquinone, respectively.

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

Procedure: Using the same procedure, napthalene- 1,4-diol and 1,4-dihydroxy-2-methyl-naphthalene were oxidized to obtain a 93% yield of 1,4-naphthoquinone and a 97% yield of 2-methyl-1,4-naphthoquinone, respectively.