Ethanol (430 mL) in two portions and 1 N hydrochloric acid (200 mL) were added to toluene-4-sulfonic acid 2-[4-amino-3-(naphthalene-1-sulfonylmethyl)-phenoxy]-ethyl ester (6.5 g, 13 mmol). A solution of sodium nitrite (1.5 g, 22 mmol) in water was then added to the reaction mixture. The reaction was heated to aid in solubility. After stirring at ambient temperature for 2 hours, solid sodium carbonate was added to basic pH. The reaction mixture was stirred at ambient temperature for one hour. It was then solvent evaporated and partitioned in water and ethyl acetate. The organic phase was washed with brine, dried with anhydrous magnesium sulfate, filtered and concentrated. The residue was purified by flash chromatography with 2% methanol in chloroform. Drying at 63° C. in vacuo yielded toluene-4-sulfonic acid 2-[3-(naphthalene-1-sulfonyl)-1H-indazol-5-yloxy]-ethyl ester a buff-colored foam (3.9 g, 59%); Mass Spectrum (+EI, [M+H]+) m/z 523. 1HNMR (500 MHz, DMSO-d6): δ14.09 (s, 1H), 8.76 (d, 1H, J=8.78 Hz), 8.52-8.55 (m, 1H), 8.27 (d, 1H, J=8.30 Hz), 8.02-8.04 (m, 1H), 7.64-7.74 (m, 3H), 7.55-7.63 (m, 2H), 7.50 (d, 1H, J=9.15 Hz), 7.27 (d, 2H, J=8.05 Hz), 7.14 (d, 1H, J=2.20 Hz), 6.94 (dd, 1H, J=9.15 Hz and 2.44 Hz), 4.32-4.34 (m, 2H), 4.18-4.20 (m, 2H), 2.25 ppm (s, 3H). Elemental Analysis for C26H22N2O6S2: Calcd: C, 59.76; H, 4.24; N, 5.36; Found: C, 59.69; H, 4.28; N, 5.14.
