2-methoxynaphthalene-1,4-dione

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

Procedure: A solution of 18.9 g of 2-methoxynaphthoquinone in methanol was added slowly to a solution of 34.8 g of sodium hydrosulfite in methanol and the mixture stirred for 1 hour. The solvent was removed under reduced pressure and the residue partitioned between ethyl acetate and water. The organic layer was dried over anhydrous sodium sulfate and evaporated to a purple solid. The solid was dissolved in 200 ml of methanol previously saturated with anhydrous hydrochloric acid and stirred for 3 minutes at 60° C. The mixture was then diluted with 200 ml of ice water and the precipitate filtered off, dried under vacuum and recrystallized from ether/pentane to give 13.25 g of 1-hydroxy-2,4-dimethoxynaphthalene, m.p. 87°-88° C. The solvent was removed under reduced pressure the residue partitioned between ethyl acetate and water The organic layer was dried over anhydrous sodium sulfate evaporated to a purple solid The solid was dissolved in 200 ml of methanol previously saturated with anhydrous hydrochloric acid stirred for 3 minutes at 60° C The mixture was then diluted with 200 ml of ice water the precipitate filtered off dried under vacuum recrystallized from ether/pentane

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

Procedure: A solution of 2-methoxy-1,4-naphthoquinone (20.0 g) in tetrahydrofuran (150 mL) was hydrogenated at atmospheric pressure over Pd-C (10%, 0.5 g) until the calculated amount of hydrogen was absorbed, approximately 4 hours. While still under a blanket of hydrogen, a solution of acetic anhydride (20 mL) and pyridine (18 mL) in tetrahydrofuran (50 mL) was added to the mixture. After stirring for 1 hour the catalyst was filtered off and the solvent removed from the filtrate under reduced pressure. The residue was dissolved in ether (100 mL) and was washed with 1M hydrochloric acid (3×50 mL) and with brine (2×50 mL). The organic layer was dried over sodium sulfate, filtered, and evaporated. Recrystallization from ether afforded 2-methoxy-1,4-diacetyloxynaphthalene, m.p. 135°-136° C. was absorbed, approximately 4 hours While still under a blanket of hydrogen, a solution of acetic anhydride (20 mL) and pyridine (18 mL) in tetrahydrofuran (50 mL) was added to the mixture was filtered off the solvent removed from the filtrate under reduced pressure The residue was dissolved in ether (100 mL) was washed with 1M hydrochloric acid (3×50 mL) and with brine (2×50 mL) The organic layer was dried over sodium sulfate filtered evaporated Recrystallization from ether

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

Procedure: A solution of 2-methoxy-1,4-naphthoquinone (20.0 g) in tetrahydrofuran (150 mL) was hydrogenated at atmospheric pressure over Pd-C (10%, 0.5 g) until the calculated amount of hydrogen was absorbed, approximately 4 hours. While still under a blanket of hydrogen, a solution of acetic anhydride (20 mL) and pyridine (18 mL) in tetrahydrofuran (50 mL) was added to the mixture. After stirring for 1 hour the catalyst was filtered off and the solvent removed from the filtrate under reduced pressure. The residue was dissolved in ether (100 mL) and was washed with 1M hydrochloric acid (3×50 mL) and with brine (2×50 mL). The organic layer was dried over sodium sulfate, filtered, and evaporated. Recrystallization from ether afforded 2-methoxy-1,4-diacetyloxynaphthalene, m.p. 135°-136° C. was absorbed, approximately 4 hours While still under a blanket of hydrogen, a solution of acetic anhydride (20 mL) and pyridine (18 mL) in tetrahydrofuran (50 mL) was added to the mixture was filtered off the solvent removed from the filtrate under reduced pressure The residue was dissolved in ether (100 mL) was washed with 1M hydrochloric acid (3×50 mL) and with brine (2×50 mL) The organic layer was dried over sodium sulfate filtered evaporated Recrystallization from ether

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

Procedure: A solution of 2-chloro-1,4-naphthoquinone (10.3 g) in tetrahydrofuran (100 mL) was treated with a suspension of sodium methoxide (3.20 g) in tetrahydrofuran (25 mL) at room temperature. After stirring overnight, the mixture was evaporated, and the residue was taken up in ether. The organic layer was washed with brine, dried, filtered and evaporated. Chromatography over silica gel gave 2-methoxy-1,4-naphthoquinone, m.p. 182°-183° C. the mixture was evaporated The organic layer was washed with brine dried filtered evaporated

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

Procedure: To a solution of 2-methoxy-5,8-dihydronaphthalene-1,4-dione (2.75 g, 14.4 mmol) in CHCl3 (60 mL, pre-treated with silica gel to remove the EtOH stabilizer) there was added a solution of Cl2 (~1.10 g, ~15.1 mmol) in EtOH-free CHCl3 (50 mL) in portions over 30 min. TLC (5% EtOAc/95% EtOH) indicated total consumption of the starting material and the appearance of a major higher Rf product spot (lower Rf impurity spots were also noted). The solvent was removed in vacuo to yield a yellow syrup. The addition of 95% EtOH (10 mL) followed by evaporation in vacuo (performed twice) yielded a yellow solid. Crystallization from 95% EtOH (dissolved in 20 mL, allowed to cool to rt) yielded a yellow solid (2.28 g, 60%, ~90% pure by TLC and 1H NMR, mp 119°-123° C.). Recrystallization from 95% EtOH (dissolved in 12 mL, allowed to cool to rt) yielded a yellow crystalline solid (1.89 g, 83% recovery, 50% total yield, ~95% pure by TLC and 1H NMR with the major impurity being 2-methoxynaphthalene-1,4-dione); mp 123°-128° C. (EtOH); 1H NMR (CDCl3) δ3.11 (m, 4H), 3.83 (s, 3H), 4.67 (m, 2H), 5.94 (s, 1H). to remove the EtOH stabilizer) there consumption of the starting material The solvent was removed in vacuo to yield a yellow syrup followed by evaporation in vacuo ( yielded a yellow solid Crystallization from 95% EtOH (dissolved in 20 mL, allowed to cool to rt) yielded a yellow solid (2.28 g, 60%, ~90% pure by TLC and 1H NMR, mp 119°-123° C.) Recrystallization from 95% EtOH (dissolved in 12 mL, allowed to cool to rt) yielded a yellow crystalline solid (1.89 g, 83% recovery, 50% total yield, ~95% pure by TLC and 1H NMR with the major impurity

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

Procedure: A solution of 2-methoxy-1,4-naphthoquinone (20.0 g) in tetrahydrofuran (150 mL) was hydrogenated at atmospheric pressure over Pd-C (10%, 0.5 g) until the calculated amount of hydrogen was absorbed, approximately 4 hours. Filtering off the catalyst under an atmosphere of nitrogen gave a solution of the desired product, which was used as such without isolation of the product as the starting material in Examples 1, 2 and 3, infra. Alternatively, the solvent is removed under reduced pressure and the residue recrystallized from diethyl ether/pentane, affording 2-methoxy-1,4-dihydroxynaphthalene. was absorbed, approximately 4 hours Filtering off the catalyst under an atmosphere of nitrogen

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

Procedure: A solution of 2-chloro-1,4-naphthoquinone (10.3 g) in tetrahydrofuran (100 mL) was treated with a suspension of sodium methoxide (3.20 g) in tetrahydrofuran (25 mL) at room temperature. After stirring overnight, the mixture was evaporated, and the residue was taken up in ether. The organic layer was washed with brine, dried, filtered and evaporated. Chromatography over silica gel gave 2-methoxy-1,4-naphthoquinone, m.p. 182°-183° C. the mixture was evaporated The organic layer was washed with brine dried filtered evaporated

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

Procedure: A solution of 2-chloro-1,4-naphthoquinone (10.3 g) in tetrahydrofuran (100 mL) was treated with a suspension of sodium methoxide (3.20 g) in tetrahydrofuran (25 mL) at room temperature. After stirring overnight, the mixture was evaporated, and the residue was taken up in ether. The organic layer was washed with brine, dried, filtered and evaporated. Chromatography over silica gel gave 2-methoxy-1,4-naphthoquinone, m.p. 182°-183° C. the mixture was evaporated The organic layer was washed with brine dried filtered evaporated

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

Procedure: A solution of 18.9 g of 2-methoxynaphthoquinone in methanol was added slowly to a solution of 34.8 g of sodium hydrosulfite in methanol and the mixture stirred for 1 hour. The solvent was removed under reduced pressure and the residue partitioned between ethyl acetate and water. The organic layer was dried over anhydrous sodium sulfate and evaporated to a purple solid. The solid was dissolved in 200 ml of methanol previously saturated with anhydrous hydrochloric acid and stirred for 3 minutes at 60° C. The mixture was then diluted with 200 ml of ice water and the precipitate filtered off, dried under vacuum and recrystallized from ether/pentane to give 13.25 g of 1-hydroxy-2,4-dimethoxynaphthalene, m.p. 87°-88° C. The solvent was removed under reduced pressure the residue partitioned between ethyl acetate and water The organic layer was dried over anhydrous sodium sulfate evaporated to a purple solid The solid was dissolved in 200 ml of methanol previously saturated with anhydrous hydrochloric acid stirred for 3 minutes at 60° C The mixture was then diluted with 200 ml of ice water the precipitate filtered off dried under vacuum recrystallized from ether/pentane

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

Procedure: A solution of 2-methoxy-1,4-naphthoquinone (20.0 g) in tetrahydrofuran (150 mL) was hydrogenated at atmospheric pressure over Pd-C (10%, 0.5 g) until the calculated amount of hydrogen was absorbed, approximately 4 hours. While still under a blanket of hydrogen, a solution of acetic anhydride (20 mL) and pyridine (18 mL) in tetrahydrofuran (50 mL) was added to the mixture. After stirring for 1 hour the catalyst was filtered off and the solvent removed from the filtrate under reduced pressure. The residue was dissolved in ether (100 mL) and was washed with 1M hydrochloric acid (3×50 mL) and with brine (2×50 mL). The organic layer was dried over sodium sulfate, filtered, and evaporated. Recrystallization from ether afforded 2-methoxy-1,4-diacetyloxynaphthalene, m.p. 135°-136° C. was absorbed, approximately 4 hours While still under a blanket of hydrogen, a solution of acetic anhydride (20 mL) and pyridine (18 mL) in tetrahydrofuran (50 mL) was added to the mixture was filtered off the solvent removed from the filtrate under reduced pressure The residue was dissolved in ether (100 mL) was washed with 1M hydrochloric acid (3×50 mL) and with brine (2×50 mL) The organic layer was dried over sodium sulfate filtered evaporated Recrystallization from ether

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

Procedure: A solution of 2-methoxy-1,4-naphthoquinone (20.0 g) in tetrahydrofuran (150 mL) was hydrogenated at atmospheric pressure over Pd-C (10%, 0.5 g) until the calculated amount of hydrogen was absorbed, approximately 4 hours. While still under a blanket of hydrogen, a solution of acetic anhydride (20 mL) and pyridine (18 mL) in tetrahydrofuran (50 mL) was added to the mixture. After stirring for 1 hour the catalyst was filtered off and the solvent removed from the filtrate under reduced pressure. The residue was dissolved in ether (100 mL) and was washed with 1M hydrochloric acid (3×50 mL) and with brine (2×50 mL). The organic layer was dried over sodium sulfate, filtered, and evaporated. Recrystallization from ether afforded 2-methoxy-1,4-diacetyloxynaphthalene, m.p. 135°-136° C. was absorbed, approximately 4 hours While still under a blanket of hydrogen, a solution of acetic anhydride (20 mL) and pyridine (18 mL) in tetrahydrofuran (50 mL) was added to the mixture was filtered off the solvent removed from the filtrate under reduced pressure The residue was dissolved in ether (100 mL) was washed with 1M hydrochloric acid (3×50 mL) and with brine (2×50 mL) The organic layer was dried over sodium sulfate filtered evaporated Recrystallization from ether

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

Procedure: A solution of 2-chloro-1,4-naphthoquinone (10.3 g) in tetrahydrofuran (100 mL) was treated with a suspension of sodium methoxide (3.20 g) in tetrahydrofuran (25 mL) at room temperature. After stirring overnight, the mixture was evaporated, and the residue was taken up in ether. The organic layer was washed with brine, dried, filtered and evaporated. Chromatography over silica gel gave 2-methoxy-1,4-naphthoquinone, m.p. 182°-183° C. the mixture was evaporated The organic layer was washed with brine dried filtered evaporated