Sodium Hydroxide → 2-(3-(Carboxymethyl)-1-hydroxy-4-methyl-1,3-dihydrobenzo[c][1,2]oxaborol-6-yloxy)isonicotinic acid

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Reaction Steps

To a solution of ethyl 2-(6-(4-cyanopyridin-2-yloxy)-1-hydroxy-4-methyl-1,3-dihydrobenzo[c][1,2]oxaborol-3-yl)acetate (1.18 g, 3.31 mmol) in MeOH/THF (12 mL, 1:1) was added aqueous NaOH solution (250 mg in 3 mL water). After stirring at room temperature for two hours, the reaction mixture was evaporated and then acidified to pH 5 using 1 N HCl and then concentrated. HPLC purification gave desired product as a white powder. 1H NMR (400 MHz, DMSO-d6) δ 9.20 (b 1H), 8.26 (d, J=5.2 Hz 1H), 7.47 (dd, J=5.2, 1.2 Hz, 1H), 7.29 (s, 1H), 7.17 (s, 1H), 7.02 (s, 1H), 5.46 (dd, J=9.6, 2.4 Hz, 1H), 3.03 (dd, J=16, 2.8 Hz, 1H), 2.24 (s, 3H), 2.08 (dd, J=15.2, 9.6 Hz, 1H). 2 protons assumed to be exchanged with solvents. MS (ESI) m/z=344 [M+H]+.

Provenance & Evidence