An ice cold solution of methyl 1-(4-fluorobenzyl)-6-methyl-4-(p-tolyl)-1H-pyrrolo[2,3-b]pyridine-5-carboxylate (2.2236 g, 5.72 mmol) in tetrahydrofuran (THF) (48.7 ml) was treated slowly with LAH (1M in THF) (17.17 ml, 17.17 mmol), and then warmed to rt overnight. The reaction was cooled to 0° C., treated slowly with 652 uL H2O, followed by 652 uL 20% aq. NaOH and 3×652 uL H2O. The mixture was stirred at rt for 1 hour, filtered, washed with Et2O and EtOAc, and then concentrated to give crude (1-(4-fluorobenzyl)-6-methyl-4-(p-tolyl)-1H-pyrrolo[2,3-b]pyridin-5-yl)methanol (2.1421 g) as light yellow solid. The intermediate was suspended in dichloromethane (DCM) (48.7 ml), treated with PCC (1.851 g, 8.59 mmol), and stirred at rt for 18 hours. The mixture was filtered through Celite™, washed with DCM and EtOAc, and then concentrated. Purification with column chromatography (0-40% EtOAc/Hexane) afforded 1-(4-fluorobenzyl)-6-methyl-4-(p-tolyl)-1H-pyrrolo[2,3-b]pyridine-5-carbaldehyde (1.68 g, 4.70 mmol, 82% yield) as off white solid: 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 10.08 (s, 1 H), 7.38-7.29 (m, 4 H), 7.30-7.23 (m, 2 H), 7.10 (d, J=3.6 Hz, 1 H), 7.04-6.97 (m, 2 H), 6.35 (d, J=3.6 Hz, 1 H), 5.49 (s, 2 H), 2.96 (s, 3 H), 2.46 (s, 3 H); LCMS (m/z) ES+=359 (M+1).
