A solution of 1-(3,4-dimethylphenyl)-3-methyl-5-oxo-3-pyrazolin-4-carbaldehyde (10 mg, 0.043 mmol) and 3′-amino-2′-hydroxybiphenyl-3-carboxylic acid hydrochloride (11 mg, 0.042 mmol) in ethanol (1 mL) was shaken with 0.2M aq. sodium acetate (0.25 mL, 0.05 mmol) for 1 h. 0.06M aq. hydrochloric acid (3 mL) was added and shaking continued for 1 h. The solid was filtered, washed with water and dried under reduced pressure to afford the title compound (14 mg, 74%) as a cream-coloured powder. 1H NMR (300 MHz, d6-DMSO) δ 13.08 (br s, 1H), 11.79 (d, J=13.8 Hz, 1H), 9.56 (s, 1H), 8.71 (d, J=13.2 Hz, 1H), 8.14 (s, 1H), 7.97 (d, J=7.8 Hz, 1H), 7.83-7.80 (m, 3H), 7.71 (d, J=8.2 Hz, 1H), 7.62 (t, J=7.8 Hz, 1H), 7.16-7.11 (m, 3H), 2.31 (s, 3H), 2.26 (s,3H), 2.22 (s, 3H).
