To a solution of 2-hydroxy-5-[3-(2-methoxy-phenyl)-1-(toluene-4-sulfonyl)-1H-pyrrolo[2,3-b]pyridin-5-yl]-benzoic acid methyl ester (52 mg, 0.10 mmol) in pyridine (0.5 mL) was added an excess of N,N,N′-trimethylethylenediamine (0.5 mL). The reaction was stirred for 16 hours at 100° C. in a scintillation vial. There appeared to be ˜50% product formation and ˜50% hydrolysis of the methyl ester to the carboxylic acid. PS-carbodiimide resin (244 mg, 0.29 mmol, 1.21 mmol/g load capacity) and DMF (1 mL) were added to the reaction solution and heating was continued for 16 hours at 70° C. The resin was filtered off and rinsed well with THF and MeOH. The filtrate was concentrated down to a yellow oil and then redissolved in a 1:1 MeOH/acetone solution (4 mL total). The solution was treated with 200 uL of a 50% KOH (aq) solution and stirred at ambient temperature for 3 hours. Glacial acetic acid was added dropwise until the pH=7. The product was extracted into ethyl acetate, whereupon the organic layer was washed with H2O, dried over Na2SO4, filtered, and concentrated under vacuum. The material was dissolved in MeOH and filtered through a 0.45 μm syringe filter. The solution was purified by reverse phase chromatography using a gradient of H2O and acetonitrile (with 0.1% formic acid as a modifier). Clean fractions were lyophilized, affording the title compound as a white powder (5.2 mg, 12% yield). 1H NMR (500 MHz, d6-DMSO) δ 11.80 (d, J=2.5 Hz, 1H), 8.49 (s, 1H), 8.19 (s, 1H), 8.10 (s, 1H), 7.74 (d, J=2.5 Hz, 1H), 7.63 (dd, J=2.0, 6.0 Hz, 1H), 7.51 (d, J=8.5 Hz, 1H), 7.43 (s, 1H), 7.33 (m, 1H), 7.17 (d, J=8.5 Hz, 1H), 7.09 (t, J=6.5 Hz, 1H), 7.01 (d, J=9.0 Hz, 1H), 3.85 (s, 3H), 3.01 (br s, 3H), 2.90 (br s, 2H), 2.59 (m, 2H), 2.36 (br s, 3H), 2.00 (br s, 3H). MS: m/z 445.1 (M+H+).
