Following the procedure for 3-(6-amino-5-benzothiazol-2-ylpyridin-3-yl)-benzoic acid methyl ester, the title compound was prepared from 6-amino-5-benzothiazol-2-yl-[3,4′]bipyridinyl-2′-carboxylic acid methyl ester (1.14 g, 3.2 mmol) and NaOH (0.48 g, 12 mmol) in MeOH (10 mL). 1H NMR (400 MHz, DMSO-d6): δ=13.0 (very brs, 1H), 8.62 (d, J=2.2 Hz, 1H), 8.29 (d, J=2.2 Hz, 1H), 8.19-8.13 (m, 3H), 8.12 (d, J=7.8 Hz, 1H), 8.04-8.00 & 7.88-7.84 (AA′BB′, 4H), 7.57 (ddd, J=1.0, 7.0, 8.0 Hz, 1H), 7.49 (ddd, J=1.0, 7.4, 8.0 Hz, 1H). MS(ES+): m/z=348.08 (100) [MH+]. HPLC: tR=3.29 min (polar—5 min, ZQ2).
