* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
With lithium chloride In DMF (N,N-dimethyl-formamide) for 0.5 h; Heating / reflux
The crude mixture of 2,5-dibromo-1-tetralone (16.08 g, 52.9 mmol,), LiCl (5.61 g, 132 mmol), and 120 mL of dry DMF were combined under an N2 atmosphere and heated to reflux (155° C.). The mixture turned dark brown. HPLC showed complete consumption of the starting material in just 0.5 h. After cooling to room temperature, the mixture was diluted with 1 N HCl (200 mL) and extracted three times with Et2O (100 mL, 25 mL, 25 mL). The Et2O layers were combined to give a brown hazy mixture (some emulsion). After stirring with decolorizing carbon (10 g, Calgon ADP) and filtration through hyflo supercel, a clear light yellow solution was obtained. This solution was extracted with 3 N NaOH (100 mL, 25 mL), leaving the non-naphtholic byproducts behind. The brown NaOH extracts were combined, acidified to pH 1 with conc. HCl, and extracted with CH2Cl2 (100 mL, 25 mL). The combined CH2Cl2 layers formed a deep red solution. After stirring with decolorizing carbon (5 g, Darco G-60) and filtration through hyflo supercel, the solution was again light yellow. An equal volume of heptane was added, and the CH2Cl2 was distilled away. When the temperature reached 75° C., gray precipitate became evident. This increased substantially on cooling to room temperature. Following filtration and drying in vacuo at 50° C., a product mixture of gray solid (5.92 g, 50.2percent) was obtained. HPLC showed this to be a mixture of 7-bromo-1-naphthol (48.3percent) and 5-bromo-1-naphthol (50.8percent). However, 1H NMR (CDCl3) integration showed that the actual ratio was about 9/1 5-Br/7-Br. Preparative reverse phase HPLC gave one peak of 5-bromo-1-naphthol as a white solid (3.22 g, 27.3percent).
27.3%
Stage #1: With lithium chloride In DMF (N,N-dimethyl-formamide) at 155℃; for 0.5 h; Heating / reflux Stage #2: With hydrogenchloride In water at 20℃;
The crude mixture of 2,5-dibromo-1-tetralone (16.08 g, 52.9 mmol,), LiCl (5.61 g, 132 mmol), and 120 mL of dry DMF were combined under an N2 atmosphere and heated to reflux (?155 C.). The mixture turned dark brown. HPLC showed complete consumption of the starting material in just 0.5 h. After cooling to room temperature, the mixture was diluted with 1 N HCl (200 mL) and extracted three times with Et2O (100 mL, 25 mL, 25 mL). The Et2O layers were combined to give a brown hazy mixture (some emulsion). After stirring with decolorizing carbon (10 g, Calgon ADP) and filtration through hyflo supercel, a clear light yellow solution was obtained. This solution was extracted with 3 N NaOH (100 mL, 25 mL), leaving the non-naphtholic byproducts behind. The brown NaOH extracts were combined, acidified to pH 1 with conc. HCl, and extracted with CH2Cl2 (100 mL, 25 mL). The combined CH2Cl2 layers formed a deep red solution. After stirring with decolorizing carbon (5 g, Darco G-60) and filtration through hyflo supercel, the solution was again light yellow. An equal volume of heptane was added, and the CH2Cl2 was distilled away. When the temperature reached 75 C., gray precipitate became evident. This increased substantially on cooling to room temperature. Following filtration and drying in vacuo at 50 C., a product mixture of gray solid (5.92 g, 50.2percent) was obtained. HPLC showed this to be a mixture of 7-bromo-1-naphthol (48.3percent) and 5-bromo-1-naphthol (50.8percent). However, 1H NMR (CDCl3) integration showed that the actual ratio was about 9/15-Br/7-Br. Preparative reverse phase HPLC gave one peak of 5-bromo-1-naphthol as a white solid (3.22 g, 27.3percent).
With lithium chloride In DMF (N,N-dimethyl-formamide) at 155℃; for 0.5 h; Heating / reflux
of 5-Bromo-1-naphthalenol. [0096] The crude mixture of 2,5-dibromo-1-tetralone (16.08 g, 52.9 mmol,), LiCl (5.61 g, 132 mmol), and 120 mL of dry DMF were combined under an N2 atmosphere and heated to reflux (155° C.). The mixture turned dark brown. HPLC showed complete consumption of the starting material in just 0.5 h. After cooling to room temperature, the mixture was diluted with 1 N HCl (200 mL) and extracted three times with Et2O (100 mL, 25 mL, 25 mL). The Et2O layers were combined to give a brown hazy mixture (some emulsion). After stirring with decolorizing carbon (10 g, Calgon ADP) and filtration through hyflo supercel, a clear light yellow solution was obtained. This solution was extracted with 3 N NaOH (100 mL, 25 mL), leaving the non-naphtholic byproducts behind. The brown NaOH extracts were combined, acidified to pH 1 with conc. HCl, and extracted with CH2Cl2 (100 mL, 25 mL). The combined CH2Cl2 layers formed a deep red solution. After stirring with decolorizing carbon (5 g, Darco G-60) and filtration through hyflo supercel, the solution was again light yellow. An equal volume of heptane was added, and the CH2Cl2 was distilled away. When the temperature reached 75° C., gray precipitate became evident. This increased substantially on cooling to room temperature. Following filtration and drying in vacuo at 50° C., a product mixture of gray solid (5.92 g, 50.2percent) was obtained. HPLC showed this to be a mixture of 7-bromo-1-naphthol (48.3percent) and 5-bromo-1-naphthol (50.8percent). However, 1H NMR (CDCl3) integration showed that the actual ratio was about 9/1 5-Br/7-Br. Preparative reverse phase HPLC gave one peak of 5-bromo-1-naphthol as a white solid (3.22 g, 27.3percent).
With potassium carbonate In acetonitrile for 2.75 h; Heating / reflux
Preparation of 7-Bromo-1-methoxynaphthalene. [CHEMMOL-00140] [0466] A slurry of 7-bromo-1-naphthol (8.89 g, 39.9 mmol), potassium carbonate (8.26 g, 59.8 mmol), dimethyl sulfate (5.66 mL, 59.8 mmol) and tetrabutylammonium bromide (0.085 g, 0.264 mmol) in acetonitrile (160 mL) was heated at reflux for 2 h 45 min. The reaction was cooled to room temperature, and water was added (200 mL). The mixture was then extracted (1.x.100, 1.x.40 mL) with CH2Cl2. The combined organic layers were washed (1.x.40 mL) with saturated aqueous NaHCO3 solution, dried over MgSO4, and concentrated. The residue was purified by medium pressure chromatography (100percent hexanes) to give the intermediate title compound as a yellow oil (8.42 g, 89percent). FDMS m/e=236 M+.
Reference:
[1] Patent: US2004/6229, 2004, A1, . Location in patent: Page/Page column 62
[2] Phosphorus and Sulfur and the Related Elements, 1984, vol. 19, p. 345 - 362
[3] Chemical and Pharmaceutical Bulletin, 1971, vol. 19, p. 1245 - 1256
6
[ 91270-69-8 ]
[ 74-88-4 ]
[ 33295-53-3 ]
Yield
Reaction Conditions
Operation in experiment
88%
With potassium carbonate In acetone at 65℃; for 2 h;
Step E: Potassium carbonate (3.3 g, 23.9 mmol) and methyl iodide (1.5 ml, 23.9 mmol) were added to a solution of the product from Step D (2.7 g, 11.9 mmol) in acetone (40 ml) at room temperature and the mixture was stirred at 65° C. for 2 hours. The solids were filtered, rinsed with ethyl acetate and the filtrate was evaporated. The residue was dissolved in ethyl acetate and washed with water twice. The aqueous layers were extracted with ethyl acetate. The combined organic extracts were washed with brine and dried over sodium sulfate to give 7-bromo-1-methoxynaphthalene (2.5 g, 88percent) after chromatography (19:1 heptane/ethyl acetate): 1H NMR (300 MHz, CDCl3) δ 8.49 (d, J=2.1 Hz, 1H), 7.68 (d, J=8.7 Hz, 1H), 7.59 (dd, J=8.7, 2.1 Hz, 1H), 7.39-7.43 (m, 2H), 6.85 (dd, J=5.4, 3.0 Hz, 1H), 3.15 (s, 3H).
Stage #1: With tetra-N-butylammonium tribromide In methanol; dichloromethane at 20℃; for 16 h; Stage #2: With lithium carbonate; lithium bromide In N,N-dimethyl-formamide at 140℃; for 1.5 h;
Step D: A solution of tetrabutylammonium tribromide (11.8 g, 24.4 mmol) in dichloromethane (80 ml) was added dropwise to a solution of the product from Step C (5.0 g, 22.2 mmol) in dichloromethane (20 ml) and methanol (20 ml) at room temperature over 1 hour. At completion of the addition, the mixture was stirred at room temperature for 15 hours and was then concentrated. The residue was taken into dichloromethane and was washed with saturated sodium bicarbonate three times. The organic layer was concentrated and the residue was dissolved in dimethylformamide (100 ml). Lithium carbonate (5.3 g, 71.1 mmol) and lithium bromide (4.1 g, 46.6 mmol) were added and the resulting mixture was stirred at 140° C. for 1.5 hours. After cooling to room temperature, the solids were filtered and rinsed with ethyl acetate. The filtrate was washed with water four times and dried over sodium sulfate to give 7-bromonaphthalen-1-ol (2.7 g, 56percent): 1H NMR (300 MHz, CDCl3) δ 8.41 (d, J=1.8 Hz, 1H), 7.68 (d, J=8.7 Hz, 1H), 7.57 (dd, J=8.7, 1.8 Hz, 1H), 7.41 (d, J=8.4 Hz, 1H), 7.28-7.35 (m, 1H), 6.62 (d, J=7.2 Hz, 1H), 5.80 (br s, 1H).
With lithium chloride In DMF (N,N-dimethyl-formamide) for 0.5 h; Heating / reflux
The crude mixture of 2,5-dibromo-1-tetralone (16.08 g, 52.9 mmol,), LiCl (5.61 g, 132 mmol), and 120 mL of dry DMF were combined under an N2 atmosphere and heated to reflux (155° C.). The mixture turned dark brown. HPLC showed complete consumption of the starting material in just 0.5 h. After cooling to room temperature, the mixture was diluted with 1 N HCl (200 mL) and extracted three times with Et2O (100 mL, 25 mL, 25 mL). The Et2O layers were combined to give a brown hazy mixture (some emulsion). After stirring with decolorizing carbon (10 g, Calgon ADP) and filtration through hyflo supercel, a clear light yellow solution was obtained. This solution was extracted with 3 N NaOH (100 mL, 25 mL), leaving the non-naphtholic byproducts behind. The brown NaOH extracts were combined, acidified to pH 1 with conc. HCl, and extracted with CH2Cl2 (100 mL, 25 mL). The combined CH2Cl2 layers formed a deep red solution. After stirring with decolorizing carbon (5 g, Darco G-60) and filtration through hyflo supercel, the solution was again light yellow. An equal volume of heptane was added, and the CH2Cl2 was distilled away. When the temperature reached 75° C., gray precipitate became evident. This increased substantially on cooling to room temperature. Following filtration and drying in vacuo at 50° C., a product mixture of gray solid (5.92 g, 50.2percent) was obtained. HPLC showed this to be a mixture of 7-bromo-1-naphthol (48.3percent) and 5-bromo-1-naphthol (50.8percent). However, 1H NMR (CDCl3) integration showed that the actual ratio was about 9/1 5-Br/7-Br. Preparative reverse phase HPLC gave one peak of 5-bromo-1-naphthol as a white solid (3.22 g, 27.3percent).
27.3%
Stage #1: With lithium chloride In DMF (N,N-dimethyl-formamide) at 155℃; for 0.5 h; Heating / reflux Stage #2: With hydrogenchloride In water at 20℃;
The crude mixture of 2,5-dibromo-1-tetralone (16.08 g, 52.9 mmol,), LiCl (5.61 g, 132 mmol), and 120 mL of dry DMF were combined under an N2 atmosphere and heated to reflux (?155 C.). The mixture turned dark brown. HPLC showed complete consumption of the starting material in just 0.5 h. After cooling to room temperature, the mixture was diluted with 1 N HCl (200 mL) and extracted three times with Et2O (100 mL, 25 mL, 25 mL). The Et2O layers were combined to give a brown hazy mixture (some emulsion). After stirring with decolorizing carbon (10 g, Calgon ADP) and filtration through hyflo supercel, a clear light yellow solution was obtained. This solution was extracted with 3 N NaOH (100 mL, 25 mL), leaving the non-naphtholic byproducts behind. The brown NaOH extracts were combined, acidified to pH 1 with conc. HCl, and extracted with CH2Cl2 (100 mL, 25 mL). The combined CH2Cl2 layers formed a deep red solution. After stirring with decolorizing carbon (5 g, Darco G-60) and filtration through hyflo supercel, the solution was again light yellow. An equal volume of heptane was added, and the CH2Cl2 was distilled away. When the temperature reached 75 C., gray precipitate became evident. This increased substantially on cooling to room temperature. Following filtration and drying in vacuo at 50 C., a product mixture of gray solid (5.92 g, 50.2percent) was obtained. HPLC showed this to be a mixture of 7-bromo-1-naphthol (48.3percent) and 5-bromo-1-naphthol (50.8percent). However, 1H NMR (CDCl3) integration showed that the actual ratio was about 9/15-Br/7-Br. Preparative reverse phase HPLC gave one peak of 5-bromo-1-naphthol as a white solid (3.22 g, 27.3percent).
With lithium chloride In DMF (N,N-dimethyl-formamide) at 155℃; for 0.5 h; Heating / reflux
of 5-Bromo-1-naphthalenol. [0096] The crude mixture of 2,5-dibromo-1-tetralone (16.08 g, 52.9 mmol,), LiCl (5.61 g, 132 mmol), and 120 mL of dry DMF were combined under an N2 atmosphere and heated to reflux (155° C.). The mixture turned dark brown. HPLC showed complete consumption of the starting material in just 0.5 h. After cooling to room temperature, the mixture was diluted with 1 N HCl (200 mL) and extracted three times with Et2O (100 mL, 25 mL, 25 mL). The Et2O layers were combined to give a brown hazy mixture (some emulsion). After stirring with decolorizing carbon (10 g, Calgon ADP) and filtration through hyflo supercel, a clear light yellow solution was obtained. This solution was extracted with 3 N NaOH (100 mL, 25 mL), leaving the non-naphtholic byproducts behind. The brown NaOH extracts were combined, acidified to pH 1 with conc. HCl, and extracted with CH2Cl2 (100 mL, 25 mL). The combined CH2Cl2 layers formed a deep red solution. After stirring with decolorizing carbon (5 g, Darco G-60) and filtration through hyflo supercel, the solution was again light yellow. An equal volume of heptane was added, and the CH2Cl2 was distilled away. When the temperature reached 75° C., gray precipitate became evident. This increased substantially on cooling to room temperature. Following filtration and drying in vacuo at 50° C., a product mixture of gray solid (5.92 g, 50.2percent) was obtained. HPLC showed this to be a mixture of 7-bromo-1-naphthol (48.3percent) and 5-bromo-1-naphthol (50.8percent). However, 1H NMR (CDCl3) integration showed that the actual ratio was about 9/1 5-Br/7-Br. Preparative reverse phase HPLC gave one peak of 5-bromo-1-naphthol as a white solid (3.22 g, 27.3percent).
With potassium carbonate;tetrabutylammomium bromide; In acetonitrile; for 2.75h;Heating / reflux;
Preparation of 7-Bromo-1-methoxynaphthalene. [CHEMMOL-00140] [0466] A slurry of 7-bromo-1-naphthol (8.89 g, 39.9 mmol), potassium carbonate (8.26 g, 59.8 mmol), dimethyl sulfate (5.66 mL, 59.8 mmol) and tetrabutylammonium bromide (0.085 g, 0.264 mmol) in acetonitrile (160 mL) was heated at reflux for 2 h 45 min. The reaction was cooled to room temperature, and water was added (200 mL). The mixture was then extracted (1×100, 1×40 mL) with CH2Cl2. The combined organic layers were washed (1×40 mL) with saturated aqueous NaHCO3 solution, dried over MgSO4, and concentrated. The residue was purified by medium pressure chromatography (100% hexanes) to give the intermediate title compound as a yellow oil (8.42 g, 89%). FDMS m/e=236 M+.
With lithium chloride; In DMF (N,N-dimethyl-formamide); for 0.5h;Heating / reflux;
The crude mixture of 2,5-dibromo-1-tetralone (16.08 g, 52.9 mmol,), LiCl (5.61 g, 132 mmol), and 120 mL of dry DMF were combined under an N2 atmosphere and heated to reflux (155° C.). The mixture turned dark brown. HPLC showed complete consumption of the starting material in just 0.5 h. After cooling to room temperature, the mixture was diluted with 1 N HCl (200 mL) and extracted three times with Et2O (100 mL, 25 mL, 25 mL). The Et2O layers were combined to give a brown hazy mixture (some emulsion). After stirring with decolorizing carbon (10 g, Calgon ADP) and filtration through hyflo supercel, a clear light yellow solution was obtained. This solution was extracted with 3 N NaOH (100 mL, 25 mL), leaving the non-naphtholic byproducts behind. The brown NaOH extracts were combined, acidified to pH 1 with conc. HCl, and extracted with CH2Cl2 (100 mL, 25 mL). The combined CH2Cl2 layers formed a deep red solution. After stirring with decolorizing carbon (5 g, Darco G-60) and filtration through hyflo supercel, the solution was again light yellow. An equal volume of heptane was added, and the CH2Cl2 was distilled away. When the temperature reached 75° C., gray precipitate became evident. This increased substantially on cooling to room temperature. Following filtration and drying in vacuo at 50° C., a product mixture of gray solid (5.92 g, 50.2percent) was obtained. HPLC showed this to be a mixture of 7-bromo-1-naphthol (48.3percent) and 5-bromo-1-naphthol (50.8percent). However, 1H NMR (CDCl3) integration showed that the actual ratio was about 9/1 5-Br/7-Br. Preparative reverse phase HPLC gave one peak of 5-bromo-1-naphthol as a white solid (3.22 g, 27.3percent).
27.3%
The crude mixture of 2,5-dibromo-1-tetralone (16.08 g, 52.9 mmol,), LiCl (5.61 g, 132 mmol), and 120 mL of dry DMF were combined under an N2 atmosphere and heated to reflux (?155 C.). The mixture turned dark brown. HPLC showed complete consumption of the starting material in just 0.5 h. After cooling to room temperature, the mixture was diluted with 1 N HCl (200 mL) and extracted three times with Et2O (100 mL, 25 mL, 25 mL). The Et2O layers were combined to give a brown hazy mixture (some emulsion). After stirring with decolorizing carbon (10 g, Calgon ADP) and filtration through hyflo supercel, a clear light yellow solution was obtained. This solution was extracted with 3 N NaOH (100 mL, 25 mL), leaving the non-naphtholic byproducts behind. The brown NaOH extracts were combined, acidified to pH 1 with conc. HCl, and extracted with CH2Cl2 (100 mL, 25 mL). The combined CH2Cl2 layers formed a deep red solution. After stirring with decolorizing carbon (5 g, Darco G-60) and filtration through hyflo supercel, the solution was again light yellow. An equal volume of heptane was added, and the CH2Cl2 was distilled away. When the temperature reached 75 C., gray precipitate became evident. This increased substantially on cooling to room temperature. Following filtration and drying in vacuo at 50 C., a product mixture of gray solid (5.92 g, 50.2percent) was obtained. HPLC showed this to be a mixture of 7-bromo-1-naphthol (48.3percent) and 5-bromo-1-naphthol (50.8percent). However, 1H NMR (CDCl3) integration showed that the actual ratio was about 9/15-Br/7-Br. Preparative reverse phase HPLC gave one peak of 5-bromo-1-naphthol as a white solid (3.22 g, 27.3percent).
With lithium chloride; In DMF (N,N-dimethyl-formamide); at 155℃; for 0.5h;Heating / reflux;
of 5-Bromo-1-naphthalenol. [0096] The crude mixture of 2,5-dibromo-1-tetralone (16.08 g, 52.9 mmol,), LiCl (5.61 g, 132 mmol), and 120 mL of dry DMF were combined under an N2 atmosphere and heated to reflux (155° C.). The mixture turned dark brown. HPLC showed complete consumption of the starting material in just 0.5 h. After cooling to room temperature, the mixture was diluted with 1 N HCl (200 mL) and extracted three times with Et2O (100 mL, 25 mL, 25 mL). The Et2O layers were combined to give a brown hazy mixture (some emulsion). After stirring with decolorizing carbon (10 g, Calgon ADP) and filtration through hyflo supercel, a clear light yellow solution was obtained. This solution was extracted with 3 N NaOH (100 mL, 25 mL), leaving the non-naphtholic byproducts behind. The brown NaOH extracts were combined, acidified to pH 1 with conc. HCl, and extracted with CH2Cl2 (100 mL, 25 mL). The combined CH2Cl2 layers formed a deep red solution. After stirring with decolorizing carbon (5 g, Darco G-60) and filtration through hyflo supercel, the solution was again light yellow. An equal volume of heptane was added, and the CH2Cl2 was distilled away. When the temperature reached 75° C., gray precipitate became evident. This increased substantially on cooling to room temperature. Following filtration and drying in vacuo at 50° C., a product mixture of gray solid (5.92 g, 50.2percent) was obtained. HPLC showed this to be a mixture of 7-bromo-1-naphthol (48.3percent) and 5-bromo-1-naphthol (50.8percent). However, 1H NMR (CDCl3) integration showed that the actual ratio was about 9/1 5-Br/7-Br. Preparative reverse phase HPLC gave one peak of 5-bromo-1-naphthol as a white solid (3.22 g, 27.3percent).
With potassium carbonate; In acetone; at 65℃; for 2h;
Step E: Potassium carbonate (3.3 g, 23.9 mmol) and methyl iodide (1.5 ml, 23.9 mmol) were added to a solution of the product from Step D (2.7 g, 11.9 mmol) in acetone (40 ml) at room temperature and the mixture was stirred at 65 C. for 2 hours. The solids were filtered, rinsed with ethyl acetate and the filtrate was evaporated. The residue was dissolved in ethyl acetate and washed with water twice. The aqueous layers were extracted with ethyl acetate. The combined organic extracts were washed with brine and dried over sodium sulfate to give 7-bromo-1-methoxynaphthalene (2.5 g, 88%) after chromatography (19:1 heptane/ethyl acetate): 1H NMR (300 MHz, CDCl3) delta 8.49 (d, J=2.1 Hz, 1H), 7.68 (d, J=8.7 Hz, 1H), 7.59 (dd, J=8.7, 2.1 Hz, 1H), 7.39-7.43 (m, 2H), 6.85 (dd, J=5.4, 3.0 Hz, 1H), 3.15 (s, 3H).
Step D: A solution of tetrabutylammonium tribromide (11.8 g, 24.4 mmol) in dichloromethane (80 ml) was added dropwise to a solution of the product from Step C (5.0 g, 22.2 mmol) in dichloromethane (20 ml) and methanol (20 ml) at room temperature over 1 hour. At completion of the addition, the mixture was stirred at room temperature for 15 hours and was then concentrated. The residue was taken into dichloromethane and was washed with saturated sodium bicarbonate three times. The organic layer was concentrated and the residue was dissolved in dimethylformamide (100 ml). Lithium carbonate (5.3 g, 71.1 mmol) and lithium bromide (4.1 g, 46.6 mmol) were added and the resulting mixture was stirred at 140° C. for 1.5 hours. After cooling to room temperature, the solids were filtered and rinsed with ethyl acetate. The filtrate was washed with water four times and dried over sodium sulfate to give 7-bromonaphthalen-1-ol (2.7 g, 56percent): 1H NMR (300 MHz, CDCl3) delta 8.41 (d, J=1.8 Hz, 1H), 7.68 (d, J=8.7 Hz, 1H), 7.57 (dd, J=8.7, 1.8 Hz, 1H), 7.41 (d, J=8.4 Hz, 1H), 7.28-7.35 (m, 1H), 6.62 (d, J=7.2 Hz, 1H), 5.80 (br s, 1H).
With potassium carbonate; In N,N-dimethyl-formamide; at 20℃; for 1h;
A mixture of <strong>[91270-69-8]7-bromonaphthalen-1-ol</strong> (0.10 g), lambda/,lambda/-dimethylformamide (2.0 mL) and potassium carbonate (0.081 g) was treated with methyl bromoacetate (0.048 mL), and the resulting mixture was stirred at room temperature for 1 hour. The mixture was diluted with water, extracted with diethyl ether and the combined extracts were washed with a saturated aqueous sodium hydrogen carbonate solution and water and then dried over magnesium sulfate. The solvent was removed under reduced pressure and the residue was purified by flash chromatography on silica gel, eluting <n="22"/>T/GB2008/003758with a mixture of petroleum ether and dichloromethane (5:1 by volume) to afford the title compound as a colourless oil (0.10 g).1H NMR (DMSO-d6): delta 3.69 (s, 3H), 5.00 (s, 2H), 6.97 (d, J = 7.4 Hz, 1H), 7.41 (t, J = 8.0 Hz, 1H), 7.51 (d, J = 8.0 Hz, 1H), 7.63 (dd, J = 2.1 , 8.7 Hz, 1H), 7.85 (d, J = 8.7 Hz, 1 H), 8.29 (d, J = 2.1 Hz1 IH).
With titanium tetrachloride; In dichloromethane; at 0 - 20℃; for 3h;
A flask was charged with TiC14 (1 M in DCM, 15.8 mL, 15.8 mmol) and DCM (12 mL). dichloromethyl methyl ether (1.27 mL, 14.4 mmol) was added, and the mixture was cooled to 0° C. A solution of <strong>[91270-69-8]7-bromonaphthalen-1-ol</strong> (1.6 g, 7.2 mmol) in DCM (10 mL) was then added dropwise. The mixture was warmed to rt and stirred 3 h, at which time TLC showed complete consumption of startingmaterial. The mixture was diluted with DCM (100 mL), and 2N HC1 (100 mL) was carefully added. The biphasic mixture was filtered to remove titanium salts, and the biphasic mixture separated. The aqueous layer was extracted with DCM (3 X 100 mL), and the combined organics were dried (MgSO4) and concentrated. The residue was purified by column chromatography (Si02, 0-100percent EtOAc/hex) to yield 6-bromo-4-hydroxy- 1 -naphthaldehyde.