“…The residue was purified by column chromatography to obtain 780 mg of Hapten 2 (DCM : MeOH = 20 : 1, 65%). 1 H NMR (400 MHz, DMSO-d 6 ) δ 12.52 (s, 1H), 12.13 (s, 1H), 9.02 (s, 1H), 8.54 (dd, J = 4.7, 1.6 Hz, 1H), 8.30-8.15 (m, 2H), 7.93 (d, J = 2.4 Hz, 1H), 7.67 (dd, J = 8.1, 4.7 Hz, 1H), 7.55 (dd, J = 8.9, 2.4 Hz, 1H), 7.19 (s, 1H), 3.33 (q, J = 6.0 Hz, 2H), 2.32 (t, J = 7.3 Hz, 2H), 1.79 ( p, J = 7.2 Hz, 2H).…”