Pyridine → 1-(Bromomethyl)naphthalene

Participants

Reaction Conditions

Reaction Steps

1-Naphthalene methanol (2.0 g, 12.7 mmol) was dissolved in toluene (30 mL) and pyridine (1.02 mL, 12.7 mmol) was added. The solution was cooled to 0° C. PBr3 (1.19 mL, 12.7 mmol) was added dropwise over 15 min. The reaction mixture was then brought up to room temperature and stirred for 1 h. The mixture was washed with K2CO3 solution and extracted with EtOAc (3×30 mL). The EtOAc layer was washed with brine and dried (MgSO4). The solvent was evaporated off in-vacuo to give 1-(bromomethyl)naphthalene (1.5 g, 53%) as a colourless oil, This intermediate was used in the following reaction. Sodium ethoxide (169 mg, 2.49 mmol) was added to DMF (5 mL) at 0° C., and the suspension was stirred for 10 min. 7-hydroxy-4-methylcoumarin (438 mg, 2.49 mmol) was slowly added and resulting mixture was stirred at this temp for 0.5 h, then allowed to reach room temperature. To this mixture 1-(bromomethyl)naphthalene (500 mg, 2.26 mmol) was added portionwise. Resulting reaction mixture was stirred at room temperature for 16 h. DMF was evaporated off in-vacuo and the residue was taken up in EtOAc, and washed with brine (2×50 mL), water (2×50 mL) and 1M NaOH (2×30 mL). The organic layer was dried (MgSO4) and product was purified by flash chromatography, eluting with hexane:EtOAc (2:1) to give 43 (200 mg, 28%) as a white solid. Mpt=181-183° C. H1 NMR (500 MHz, acetone-d6): δ=8.10 (1H, d, ArH), 8.00-7.99 (2H, m, Ar), 7.97-7.71 (2H, m, ArH), 7.70-7.53 (3H, m, ArH), 7.24 (1H, s, ArH), 7.09 (1H, d, CH), 6.23 (1H, s, CH), 5.68 (2H, s, CH2), 2.40 (3H, s, CH3).

Provenance & Evidence