* 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.
A catalyst is prepared according to the method described above, and is finally subjected to heat treatment in air at 450 °C. The sample does not contain magnesium and is therefore constituted solely by Fe203. One obtains a conversion of 48percent, with selectivity to 2-methyl-1-naphthol equal to 84percent. The byproducts are essentially constituted by 4-methyl-1-naphthol and by products of methylation of the aromatic ring.
31%
magnesium oxide;Conversion of starting material;
A catalyst is prepared according to the method described above, and is finally subjected to heat treatment in air at 450degree;C. The sample does not contain iron, and therefore is constituted only by MgO. One obtains 42percent conversion, with selectivity to 2-methyl-l-naphthol equal to 74 percent. The byproducts are essentially constituted by 4-methyl-l-naphthol and by products of methylation of the aromatic ring.
A. 2-(4-Methyl-1-naphthalenyloxy)ethylchloride. A 250 ml three-neck round bottom flask fitted with a thermometer, nitrogen inlet tube and magnetic stirrer was charged with 1.09 g (6.9 mmol) of <strong>[10240-08-1]4-methyl-1-naphthol</strong> and 75 ml of N,N-dimethylformamide. To the mixture was added 331 mg (8.3 mmol) of sodium hydride and the resulting mixture was stirred for approximately 15 minutes. Next, 1.6 ml (13.8 mmol) of 2-chloroethylmethanesulfonate was added and the resulting mixture was heated at about 70 C. for approximately 16 hours. The mixture was cooled and diluted with water. The mixture was extracted twice with diethyl ether. The organic extracts were combined and washed twice with water, once with a saturated sodium chloride solution and dried over anhydrous sodium sulfate. The mixture was filtered and concentrated under vacuum to provide 1.8 g of a dark oil. This material was combined with approximately 19 g of additional material prepared by the same process and purified by high pressure liquid chromatography to provide 9.76 g. A NMR of the material verified the structure of the desired compound.
In N,N-dimethyl-formamide;
A. 2-(4-Methyl-1-naphthalenyloxy)ethylchloride. A 250 ml three-neck round bottom flask fitted with a thermometer, nitrogen inlet tube and magnetic stirrer was charged with 1.09 g (6.9 mmol) of <strong>[10240-08-1]4-methyl-1-naphthol</strong> and 75 ml of N,N-dimethylformamide. To the mixture was added 331 mg (8.3 mmol) of sodium hydride and the resulting mixture was stirred for approximately 15 minutes. Next, 1.6 ml (13.8 mmol) of 2-chloroethylmethanesulfonate was added and the resulting mixture was heated at about 70C for approximately 16 hours. The mixture was cooled and diluted with water. The mixture was extracted twice with diethyl ether. The organic extracts were combined and washed twice with water, once with a saturated sodium chloride solution and dried over anhydrous sodium sulfate. The mixture was filtered and concentrated under vacuum to provide 1.8 g of a dark oil. This material was combined with approximately 19 g of additional material prepared by the same process and purified by high pressure liquid chromatography to provide 9.76 g. A NMR of the material verified the structure of the desired compound.
EXAMPLE 2 Example 1 was repeated using <strong>[10240-08-1]4-methyl-1-naphthol</strong>. The yield of phenyl 1-hydroxy-4-methyl-2-naphthoate (light tan, m.p. 76-77 C.) obtained was 45%.
Hydrolysis 4-Methyl-1-methoxynaphthalene (4) (145 g) was mixed with pyridine hydrochloride (250 g) and the mixture was heated at 200 C. for 3 hours. The mixture was cooled, treated with dilute hydrochloric acid, and extracted with ether. The ether extract was dried (MgSO4), filtered and the solvent removed, leaving a black oil which was extracted with petroleum b.p. 60-80 C. (4*100 cm3). 4-Methyl-1-naphthol (5) was obtained as near colourless oily crystals which darken on storage.
Preparation of substituted naphthol starting materials 4-Methyl-1-naphthol (5) (see FIG. 10 of the accompanying drawings) Formylation Phosphorus oxychloride (315 g, 1.6 mole) was added dropwise over 4 hours to a stirred solution of 1-methoxynaphthalene (250 g) (2) in dried dimethylformamide (150 g). the reaction mixture was heated on a water bath for a further 4 hours, cooled, and poured onto ice (1 k) and 2M aqueous sodium acetate (1.5 l). The organic layer was extracted with dichloromethane (1 l) and washed with dilute hydrochloric acid and then with water. The organic layer was dried (MgSO4), filtered, and the solvent removed. 4-Methoxy-1-naphthaldehyde (3) was obtained as a pale yellow oil.
General procedure: A borosilicate flask was equipped with a magnetic stir bar, and neat or solid arene (0.2-0.8mmol) was added. Addition of hexafluoroisopropanol or trifluoroethanol (2-5 ml) to providea 0.2M solution was followed by the addition of solid phthaloyl peroxide (1, 1.3 equiv.) in portions over 90 s. The reaction flask was placed in a heated oil bath (23-50 C). After 3-24 h, the flask was removed from the oil bath and cooled to ambient temperature (23 C). The reaction was then concentrated, and under positive N2 pressure (to avoid potential air oxidation of the phenolic product) MeOH (3 ml) and saturated aqueous NaHCO3 solution (0.2 ml) were added and the solution was stirred. After 12 h, the reaction was quenched with phosphate buffer (5 ml, pH 7.0) and extracted with EtOAc (10 ml x 33), and the combined organic layers were washed with brine (5 ml), dried over Na2SO4 and concentrated. The crude material was purified by silica-gel column chromatography to afford the desired phenolic product. For full experimental details and characterization of new compounds, see Supplementary Information.
General procedure: General procedure for the hydroxylation of arenes: A borosilicate flask was equipped with a magnetic stir bar and neat or solid arene (0.2-0.8 mmol) was added. Addition of HFIP or TFE (2-5 mL) to provide a 0.2 M solution was followed by the addition of solid phthaloyl peroxide (1, 1.3 equiv.) in portions over 90 seconds. The reaction flask was placed in a heated oil bath (23-50 C). After 3-24 hours, the reaction was removed from the oil bath and cooled to ambient temperature (23 C). The reaction was then concentrated and under positive N2 pressure (to avoid potential air oxidation of the phenolic product) MeOH (3 mL) and saturated aqueous NaHC03 solution (0.2 mL) were added and the solution was stirred. After 12 hours, the reaction was quenched with pH 7.0 phosphate buffer (5 mL) and extracted with EtOAc (10 mL x 3) and the combined organic layers were washed with brine (5 mL), dried over Na2S04, and concentrated. The crude material was purified by silica gel column chromatography to afford the desired phenolic product.