tert-Butyl 13-cyclohexyl-3-methoxy-6-(4-(methoxycarbonyl)-1,3-oxazol-5-yl)-7H-indolo[2,1-a][2]benzazepine-10-carboxylate (205 mg, 0.360 mmol) was dissolved in THF (3.0 ml) and tetrabutylammonium hydroxide (1.1 mL, 1.100 mmol) (1.0M in methanol) was added to the reaction. The reaction was capped and stirred at room temperature for 2 hrs. A 0.1M aqueous solution of NaH2PO4 was added to the reaction followed by 0.1N aqueous hydrochloric acid. The product was extracted into ethyl acetate and the organic phase washed sequentially with 0.1N aqueous hydrochloric acid, 0.1M aqueous NaH2PO4, brine and dried over magnesium sulfate. The product solution was filtered, solvent removed and product dried in vacuo to yield 191 mg of a yellow solid. 1H NMR (500 MHz, CHLOROFORM-D) δ ppm 0.77-0.94 (m, 1H) 1.12-1.31 (m, 3H) 1.30-1.59 (m, 5H) 1.62 (s, 9H) 1.76 (d, J=11.29 Hz, 2H) 1.87-2.18 (m, 4H) 2.76-2.90 (m, 1H) 3.91 (s, 3H) 4.45 (d, J=14.04 Hz, 1H) 6.03 (d, J=12.21 Hz, 1H) 7.03 (d, J=2.44 Hz, 1H) 7.08 (dd, J=8.55, 2.75 Hz, 1H) 7.53 (d, J=8.85 Hz, 1H) 7.68 (d, J=8.24 Hz, 1H) 7.82 (d, J=8.55 Hz, 1H) 7.91 (s, 1H) 8.21 (d, J=5.80 Hz, 2H). LC-MS retention time 1.86 min; m/z 553 (MH−). LC data was recorded on a Shimadzu LC-10AS liquid chromatograph equipped with a Waters Xterra MS 7u C18 3.0×50 mm column using a SPD-10AV UV-Vis detector at a detector wave length of 220 nM. The elution conditions employed a flow rate of 5 ml/min, a gradient of 100% solvent A/0% solvent B to 0% solvent A/100% solvent B, a gradient time of 3 min, a hold time of 1 min, and an analysis time of 4 min where solvent A was 5% acetonitrile/95% H2O/10 mM ammonium acetate and solvent B was 5% H2O/95% acetonitrile/10 mM ammonium acetate. MS data was determined using a Micromass Platform for LC in electrospray mode.
