To a solution of the product of Step 1 (16.5 g, 35.3 mmol) in methanol (115 mL) was added sodium hydroxide (1M, 123 mL, 123 mmol) and the mixture was heated to 70° C. for 2.5 hours. The reaction was cooled to 30° C. and hydrochloric acid (1 N, 123 mL, 123 mmol) was added. The reaction was aged for 1.5 hours and filtered to provide 15.3 g (33.7 mmol, 96%) of the title compound as a white solid. MS ESI: [M+H]+ m/z 453.0. 1H NMR (600 MHz, DMSO-d6) δ 11.98 (s, 1H), 9.55 (s, 1H), 8.32 (d, J=5.0, 1H), 7.94 (s, 1H), 7.88 (s, 1H), 7.49 (s, 1H), 7.02 (s, 1H), 6.72 (d, J=5.0, 1H), 5.86 (s, 1H), 2.34 (s, 3H), 2.27 (s, 3H), 2.14 (dd, J=12.7, 3.1, 1H), 2.00 (ddd, J=18.6, 13.2, 6.0, 1H), 1.88-1.77 (m, 3H), 1.62 (d, J=14.1, 1H), 1.55 (dq, J=13.5, 3.3, 1H), 1.09 (s, 3H), 0.97 (s, 3H). rhSYK activity=+++
