A mixture of tert-butyl 4-[N-(5-acetamido-6-cyanoindan-1-yl)amino]-2-fluorobenzoate (0.182 g, 0.44 mmol), ethanol (2 ml), and water (0.4 ml) was cooled in an ice-bath, then 30% aqueous H2O2 solution (0.37 ml) was added followed by granulated sodium hydroxide pellets (0.030 g, 0.75 mmol). The reaction mixture was stirred at ˜0° C. for 10 min, then it was placed in an oil bath preheated to 55° C. and stirred at this temperature for 30 min The reaction mixture was allowed to cool to room temperature, then the solvents were removed in vacuo and the residue was suspended in water (˜15 ml). The pH of this mixture was adjusted to ˜4 with 1N hydrochloric acid. The white precipitate was collected by filtration, washed with water, and dried in vacuo over P2O5. The desired compound was obtained as a white solid 0.155 g (85%), m.p. 150-152° C.; 1H-N (250 MHz, DMSO-d6, TMS) 1.50 (s, 9H, C(C3)3), 2.32 (s, 3H, 2-CH3), 1.83, 2.53 (2×m, 2H, 7-H), 3.00 (m, 2H, 8-H), 5.15 (q, J=7.40 Hz, 1H, 6-H), 6.57 (m, 2H, 3′,5′-H), 7.16 (d, J=7.75 Hz, 1H, N10—H), 7.44, 7.87 (2×s, each 1H, 5-H, 9-H), 7.59 (t, J=8.73 Hz, 6′-H), 12.11 (s, 1H, N3-H), MS (ESI, m/z) 819 {(2M+H)+, 100%}, 432 {(M+Na)+, 10%}, 410 {M+H)+, 15%}; Found: C, 66.81; H, 5.89, N, 10.11; F, 4.58; C23H24FN3O30.25H2O requires C, 66.74; H, 5.96; N, 10.15%; F, 4.59%.
