Hydrochloric Acid → (4-{[3-(Methoxy)propyl]thio}phenyl)boronic acid

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Reaction Steps

A mixture of 4-mercaptophenylboronic acid (1.0 g, 90%, 5.84 mmol), 1-bromo-3-methoxypropane (1.83 g, 11.7 mmol), K2CO3 (2.45 g, 17.5 mmol) and catalytic amount of Nal in CH3CN (20 mL) was stirred at ambient temperature overnight. After CH3CN was removed, water was added to the residue, and the mixture was extracted with CH2Cl2. The combined organic extract was washed with brine, dried over Na2SO4, filtered, and the filtrate was concentrated to give a milky oil. Water was added to this oily residue, and the aqueous layer was acidified to pH about 2 with concentrated HCl. The mixture was let stand at ambient temperature overnight, and the off-white solid was collected via filtration and washed with water and hexane to give 1.07 g (81%) of (4-{[3-(methoxy)propyl]thio}phenyl)boronic acid as an off-white solid. 1H NMR (400 MHz, DMSO-d6): δ 7.98 (s, 2H), 7.68 (d, 2H, J=8.0 Hz), 7.22 (d, 2H, J=8.1 Hz), 3.38 (t, 2H, J=6.1 Hz), 3.19 (s, 3H), 2.98 (t, 2H, J=7.2 Hz), 1.85-1.70 (m, 2H); LRMS (ESI), m/z 225 (M−H).

Provenance & Evidence