Pyridine → 1-(Bromomethyl)naphthalene

Participants

Reaction Conditions

Reaction Steps

Naphthalen-2-ylmethanol (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 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 crude 1-(bromomethyl)naphthalene. This intermediate was used in the following reactions. 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 temp. 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 44 (1.44 g, 36%) as a white solid. m/z=317.12 (M+H), 633.24 (2M+H). H1 NMR (500 MHz, CDCl3): δ=7.93-7.87 (4H, m, ArH), 7.58-7.52 (4H, m, Ar), 6.97 (1H, t, J=2.43 Hz, ArH), 6.16 (1H, s, ArH), 5.32 (2H, s, CH2), 2.41 (3H, s, CH3).

Provenance & Evidence