Water → 7-[4-(4-Butyl-phenylethynyl)-benzylamino]-2,2-dimethyl-benzo[1,3]dioxin-4-one

Participants

Reaction Conditions

Reaction Steps

A solution of 4-[(4-butylphenyl)ethynyl]benzaldehyde (2.0 g, 7.63 mmol, intermediate which may be obtained according to methods disclosed in EP03103780.7) and 7-amino-2,2-dimethyl-4H-1,3-benzodioxine-4-one (1.47 g, 7.63 mmol) in toluene (30 mL) was heated at reflux for 96 hrs with azeotropic removal of water. The reaction mixture was concentrated off under reduced pressure. MeOH (15 mL) and THF (15 mL) were then added, and the resulting mixture chilled at 0° C. Sodium borohydride (375 mg, 9.9 mmol) was added portionwise and the mixture was stirred for 1 hr at 0° C., then 3 hrs at room temperature. The reaction mixture was diluted with EtOAc (60 mL) and washed with an aqueous solution of NaOH (3×15 mL, 1N). The organic layer was dried over MgSO4 and the solvents were removed under reduced pressure. Et2O (100 mL) was added and the resulting white precipitate was filtered off to give 2.2 g (66%) of the title compound as a white solid. HPLC, Rt: 5.62 min (purity: 93.6%). LC/MS, M−(ESI): 438.3, M+(ESI): 440.2. 1H NMR (CDCl3) δ: 7.71 (d, J=8.6 Hz, 1H), 7.50 (d, J=8.3 Hz, 2H), 7.42 (d, J=8.3 Hz, 2H), 7.29 (d, J=7.9 Hz, 2H), 7.14 (d, J=7.9 Hz, 2H), 6.32 (m, 1H), 6.01 (m, 1H), 4.38 (s, 2H), 2.61 (t, J=7.5 Hz, 2H), 1.60 (s, 6H), 1.65-1.50 (m, 2H), 1.42-1.28 (m, 2H), 0.91 (t, J=7.5 Hz, 3H).

Provenance & Evidence