Boron tribromide → HCID 25149592, compound

Participants

Reaction Steps

To a solution of diethyl 3,5-dichloro-4-(3′-iso-propyl-4′-methoxyphenoxy)benzylphosphonate (0.59 g, 1.28 mmol) in CH2Cl2 (10.0 mL) at −30° C. was added bromotrimethylsilane (2.53 mL, 19.2 mmol). The reaction mixture was stirred at room temperature for 16 h and the solvent was removed under reduced pressure. The residue was dissolved in dichloromethane (25.0 mL), cooled to −78° C. and to it was added BBr3 (19.0 mL, 19.0 mmol, 1.0 M solution in CH2Cl2). The reaction mixture was stirred at −78° C. for 10 min, allowed to warm to room temperature and stirred for 16 h. The reaction mixture was poured into ice, concentrated and extracted with ethyl acetate. The organic layer was washed with water (20 mL×2), dried over MgSO4 and filtered. The solvent was removed under reduced pressure to afford 3,5-dichloro-4-(3′-iso-propyl-4′-hydroxyphenoxy)benzylphosphonic acid as a brown solid (0.20 g, 40%): mp: 178-181° C.; LC-MS m/z=391 [C16H17Cl2O5P−H]−; 1H NMR (300 MHz, DMSO-d6): δ 9.08 (s, 1 H), 7.48 (s, 2 H), 6.72 (m, 2 H), 6.25 (m, 1 H), 3.18 (m, 1 H), 3.00 (d, J=21.0 Hz, 2 H), 3.11 (m, 1 H), 1.14 (d, J=6.0 Hz, 6 H); Anal. Calcd for (C16H17Cl2O5P+0.2 C4H8O2+0.5H2O): C, 48.30; H, 4.73. Found: C, 48.69, H, 5.16.

Provenance & Evidence