1,4-dimethoxyanthracene

反応条件: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: A solution of 0.70 g (2.90 mmol) of 2 and 1.00 g (7.20 mmol) of 6 in 10 mL of toluene in a sealed tube was heated at 150° C. for 1 day, cooled to 25° C., concentrated to dryness, and column chromatographed on silica gel using a gradient mixture of hexane and ethyl acetate as solvent gave 0.52 g (48% yield) of compounds 5 as a mixture of exo- and endo-(1:1) isomers along with 0.62 g of 6. The exo- and endo-isomers were partially separated by silica gel column and the stereochemistry have not assigned. Compound 5, less polar isomer: MS, m/z 376 (M+), 375. 1H NMR d 7.24-7.18 (m, 2H), 7.08-7.04 (m, 2H), 6.65 (s, 2H, C6,7 Hs), 5.61 (s, 1H), 5.33 (bs, 2H), 3.82 (s, 6H, OMe), 3.48 (s, 3H, OMe), 3.12 (ABd, J=9 Hz, 1H), 3.06 (ABd, J=9 Hz, 1H). More polar isomer: MS, m/z 376 (M+), 375. 1H NMR d 7.40 (m, 2H), 7.16 (m, 2H), 6.60 (ABd, J=8.8 Hz, 1H), 6.56 (Abd, J=8.8 Hz, 1H), 5.65 (s, 1H, ═CH), 5.33 (bs, 2H, C9,10 Hs), 3.76 (s, 3H, OMe), 3.73 (s, 3H, OMe), 3.51 (s, 3H, OMe), 3.13 (Abd, J=9 Hz, 1H), 3.08 (Abd, J=9 Hz, 1H). This mixture of compounds was used in the next step. concentrated to dryness, and column chromatographed on silica gel using a gradient mixture of hexane and ethyl acetate as solvent

反応条件: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: A solution of 0.70 g (2.90 mmol) of 2 and 1.00 g (7.20 mmol) of 6 in 10 mL of toluene in a sealed tube was heated at 150° C. for 1 day, cooled to 25° C., concentrated to dryness, and column chromatographed on silica gel using a gradient mixture of hexane and ethyl acetate as solvent gave 0.52 g (48% yield) of compounds 5 as a mixture of exo- and endo-(1:1) isomers along with 0.62 g of 6. The exo- and endo-isomers were partially separated by silica gel column and the stereochemistry have not assigned. Compound 5, less polar isomer: MS, m/z 376 (M+), 375. 1H NMR d 7.24-7.18 (m, 2H), 7.08-7.04 (m, 2H), 6.65 (s, 2H, C6,7 Hs), 5.61 (s, 1H), 5.33 (bs, 2H), 3.82 (s, 6H, OMe), 3.48 (s, 3H, OMe), 3.12 (ABd, J=9 Hz, 1H), 3.06 (ABd, J=9 Hz, 1H). More polar isomer: MS, m/z 376 (M+), 375. 1H NMR d 7.40 (m, 2H), 7.16 (m, 2H), 6.60 (ABd, J=8.8 Hz, 1H), 6.56 (Abd, J=8.8 Hz, 1H), 5.65 (s, 1H, ═CH), 5.33 (bs, 2H, C9,10 Hs), 3.76 (s, 3H, OMe), 3.73 (s, 3H, OMe), 3.51 (s, 3H, OMe), 3.13 (Abd, J=9 Hz, 1H), 3.08 (Abd, J=9 Hz, 1H). This mixture of compounds was used in the next step. concentrated to dryness, and column chromatographed on silica gel using a gradient mixture of hexane and ethyl acetate as solvent

反応条件: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: To a 0.275 g (11.0 mmol) of pre-washed (with distilled diethyl ether) sodium hydride under argon were added 1.00 g (4.80 mmol) of 1,4-dihydroxyanthracene, 0.75 mL (12.0 mmol) of iodomethane, and 10 mL of DMF (distilled over CaH2). The solution was stirred at 25° C. for 1.5 h, diluted with 20 mL of water, and acidified with 6 N HCl (pH ˜2). The mixture was extracted three times with ethyl acetate, and the combined extract was washed twice with water, and brine, dried (MgSO4), concentrated to give 1.07 g (94% yield) of compound 2. Recrystallization from ether:hexane (1:1) gave 0.89 g (78% yield) of yellow solids: mp 132-133° C. (Lit.6 134-136° C.); MS, FAB, m/z 239 (M+1), 238 (M+); 1H NMR d 8.70 (s, 2H, C9,10H), 7,97 (dd, J=6.1, 3.6 Hz, 2H, C5,8H), 7.40 (dd, J=6.6, 3.2 Hz, 2H, C6,7H ), 6.55 (s, 2H, C2,3H), 3.97 (s, 6H, OCH3); 13C NMR d 149.5 (s, C8a,10a), 131.5 (s, C4a,9a), 128.5 (d, C9,10), 125.5 (d, C5,8), 120.7 (d, C6,7), 100.9 (d, C2,3), 55.6 (s, OCH3). To a 0.275 g (11.0 mmol) of pre-washed (with distilled diethyl ether) sodium hydride under argon The mixture was extracted three times with ethyl acetate the combined extract was washed twice with water, and brine dried (MgSO4) concentrated

反応条件: temp:25.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: To a 0.275 g (11.0 mmol) of pre-washed (with distilled diethyl ether) sodium hydride under argon were added 1.00 g (4.80 mmol) of 1,4-dihydroxyanthracene, 0.75 mL (12.0 mmol) of iodomethane, and 10 mL of DMF (distilled over CaH2). The solution was stirred at 25° C. for 1.5 h, diluted with 20 mL of water, and acidified with 6 N HCl (pH ˜2). The mixture was extracted three times with ethyl acetate, and the combined extract was washed twice with water, and brine, dried (MgSO4), concentrated to give 1.07 g (94% yield) of compound 2. Recrystallization from ether:hexane (1:1) gave 0.89 g (78% yield) of yellow solids: mp 132-133° C. (Lit.6 134-136° C.); MS, FAB, m/z 239 (M+1), 238 (M+); 1H NMR d 8.70 (s, 2H, C9,10H), 7,97 (dd, J=6.1, 3.6 Hz, 2H, C5,8H), 7.40 (dd, J=6.6, 3.2 Hz, 2H, C6,7H ), 6.55 (s, 2H, C2,3H), 3.97 (s, 6H, OCH3); 13C NMR d 149.5 (s, C8a,10a), 131.5 (s, C4a,9a), 128.5 (d, C9,10), 125.5 (d, C5,8), 120.7 (d, C6,7), 100.9 (d, C2,3), 55.6 (s, OCH3). To a 0.275 g (11.0 mmol) of pre-washed (with distilled diethyl ether) sodium hydride under argon The mixture was extracted three times with ethyl acetate the combined extract was washed twice with water, and brine dried (MgSO4) concentrated

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: Although the preparation of 1,4-dimethoxyanthracene (1) has been reported (Criswell, et al., J. Org. Chem. 1974, 39, 770-774) by using methylation of quinizarin (3) followed by sequential reduction of the diketo function with sodium borohydride in diglyme, the difficulty in the reduction steps prompted us to investigate an easier method in the preparation of 1. Reduction of 3 with sodium borohydride in MeOH followed by quenching with HCl gave a 95% yield of 1,4-anthraquinone (4) (Scheme 2). Reduction of the quinone moiety of 4 with aqueous sodium hydrosulfite in 1,4-dioxane provided 1,4-dihydroxyanthracene (5). Methylation of 5 with sodium hydride in DMF at room temperature gave excellent yield of 1. in the preparation of 1 by quenching with HCl