Sodium Chloride → 6-({4-[(4-butylphenyl)ethynyl]benzyl}amino)-2,2-dimethyl-4H-1,3-benzodioxin-4-one

Participants

Reaction Conditions

Reaction Steps

A solution of 4-[(4-butylphenyl)ethynyl]benzaldehyde (5.43 g, 20.7 mmol, intermediate which may be obtained according to methods disclosed in EP03103780.7) and 6-amino-2,2-dimethyl-4H-1,3-benzodioxin-4-one (4.00 g, 20.7 mmol) in toluene (60 mL) was heated at reflux for 3.5 hours with azeotropic removal of water. Then the mixture was cooled down to 0° C. and anhydrous THF (60 mL) and MeOH (60 1L) were added NaBH4 (1.65 g, 43.6 mmol) was added portionwise and the reaction mixture was stirred for 30 min at 0° C. and 45 min at rt. The reaction mixture was poured into a saturated solution of NaCl and extracted with Et2O. The combined organic layers were dried over MgSO4 and the solvents were removed under reduced pressure to give the crude product. Precipitation from a mixture of EtOAc/MeOH gave 7.1 g (75%) of the title compound as a yellow powder. HPLC, Rt: 5.4 min (purity: 97.5%). 1H NMR (CDCl3) δ: 7.45 (d, J=8.3 Hz, 2H), 7.39 (d, J=8.3 Hz, 2H), 7.28 (d, J=8.3 Hz, 2H), 7.15-7.06 (m, 3H), 6.80-6.70 (m, 2H), 4.20 (m, 2H), 4.04 (brs, 1H), 2.57 (t, J=7.7 Hz, 2H), 1.65 (s, 6H), 1.61-1.49 (m, 2H), 1.37-1.23 (m, 2H), 0.88 (t, J=7.3 Hz, 3H).

Provenance & Evidence