*4.17. Synthesis and Chemical Characterization of the Extracellular Chelator EC1*

2-Hydroxybenzaldehyde (125 mg, 1.0 mmol) was added to a solution of sodium 4-(hydrazinecarbothioamido) benzenesulfonate (426 mg, 1.5 mmol) in water (1 mL). Ethanol (2 mL) was added and the solution was brought to reflux and stirred for 30 min. The reaction mixture was then allowed to cool to room temperature and the formed precipitate was filtered, washed with ethanol, and dried under vacuum. The identity and purity of the desired product (311 mg, 81% yield) were confirmed by high-resolution mass spectrometry via electrospray ionization (HRMS-ESI) and nuclear

magnetic resonance (NMR) spectroscopy. HRMS-ESI (*m*/*z*): [M – Na]<sup>−</sup> calcd for [C14H12-N3O4S2] −, 350.02747; found, 350.02741; [M + H]<sup>+</sup> calcd for [C14H13-N3NaO4S2] <sup>+</sup>, 374.02397; found, 374.02401. 1H NMR (500 MHz, DMSO-*d*6) δ 11.79 (s, 1H), 10.07 (s, 1H), 9.98 (bs, 1H), 8.50 (s, 1H), 8.09 (bd, 1H), 7.64–7.44 (m, 4H), 7.24 (m, 1H), 6.95–6.78 (m, 2H). 13C NMR (125 MHz, DMSO-*d*6) δ 176.21, 157.17, 145.37, 140.65, 139.76, 131.86, 127.55, 125.85, 125.12, 120.69, 119.70, 116.53.
