Name | 4-bromonaphthalen-2-ol |
Synonyms | 4-bromonaphthalen-2-ol 4-Bromo-2-naphthalenol 2-Naphthalenol, 4-bromo- 1-Bromo-3-hydroxynaphthalene |
CAS | 5498-31-7 |
Molecular Formula | C10H7BrO |
Molar Mass | 223.07 |
Density | 1.614±0.06 g/cm3(Predicted) |
Melting Point | 122 °C |
Boling Point | 346.8±15.0 °C(Predicted) |
pKa | 8.76±0.40(Predicted) |
Storage Condition | Keep in dark place,Sealed in dry,Room Temperature |
MDL | MFCD01712260 |
Use | The application of 1-bromo-3-hydroxynaphthalene is also called 4-bromaphthalene-2-ol. It can be brominated from naphthalene-1-amine to obtain 2,4-dibromaphthalene-1-amine, and then through diazotization The reaction obtains 4-bromo-1-diazo-naphthalene-2-phenol, and finally reduces by sodium borohydride to obtain 1-bromo-3-hydroxynaphthalene. |
step a: 2,4-dibromnaphthalene-1-amine: add the solution of naphthalene-1-amine (101g,705mmol,99.0mL,1.00eq) in AcOH(500mL) to the solution of Br2(246g,1.54mol,79.3mL,2.18eq) in AcOH(750mL) at ambient temperature, and stir for reaction at 70 ℃ for 1 hour. The reaction mixture was cooled at room temperature and filtered. The cake was washed with AcOH(300mL) and then added to the 20% NaOH aqueous solution (1.2L). Stir the mixture for 20 minutes and filter. The separated solid was washed with water (1L) and dried in vacuum to obtain 2, 4-dibromnaphthalene-1-amine (200g,664mmol,94.2% yield) in a gray solid form. ESI MS m/z 301.9[M H].
step B:4-bromo -1-diazo-naphthalene -2-phenol: NaNO2(16.5g,239mmol,13.0mL,1.20eq) was added to the solution of 2,4-dibromonaphthalene -1-amine (60.0g,199mmol,1.00eq) in AcOH(900mL) and propionic acid (150mL) at 5-8 ℃ for 30 minutes, the reaction mixture was then stirred at 5-8°C for 30 minutes. The reaction mixture is poured into ice water (4000mL), and the resulting solid is collected and washed with water (2 x 50mL) to obtain a gray solid 4-bromo -1-diazo-naphthalene-2-phenol (150g, wet crude), which is directly used in the next step. 1H NMR(400MHz,CDCl3)& delta;8.12-8.10(d,J = 8.4Hz,1H),7.62-7.58(t,J = 7.6Hz,1H),7.41-7.37(t,J = 7.6Hz,1H),7.31-7.29(d,J = 8.0Hz,1H),7.20(s,1H).
Step C:4-bromnaphthalene-2-ol: NaBH4(30.4g,803mmol,2.00eq) is added to a solution of 4-bromo -1-diazo-naphthalene-2-phenol (100g,402mmol,1.00eq) in EtOH(2.00L) for 1 hour at 13-15°C, and the reaction mixture is stirred at 15-18°C for 3 hours. The reactants are filtered and concentrated to dry. The residue was dissolved in DCM(1000mL) and washed with water (500mL × 2). The organic phase was dried by Na2SO4 and concentrated to dry. The residue was purified by silica gel column chromatography with ether/ethyl acetate (60:1 to 10:1) elution. The separated product was repurified by reversed-phase HPLC to obtain a gray solid 4-bromnaphthalene-2-ol (40.0g,139mmol,17.3% yield, 77.4% purity).