Synthesis
（Synthesis of (a) 3-methyl-1H-pyrrolo[2,3-b]pyridine: The intermediate was prepared by the method described by Jensen et al. (Angew. Chem. Int. Ed. 2008, 47, 888-890). Toluene (5 mL), 2,3-dichloropyridine (300 mg, 2.03 mmol), tris(dibenzylideneacetone)dipalladium (Pd2dba3, 2 mg, 0.0025 mmol), 1,1'-bis(diphenylphosphino)ferrocene (dppf, 6 mg, 0.01 mmol), sodium tert-butoxide (NaOtBu, 487 mg , 5.07 mmol) and allylamine (0.15 mL, 2.03 mmol). The reaction tube was sealed and heated at 140 °C for 20 h, followed by stirring for 24 h at room temperature. The reaction mixture was washed sequentially with water and brine, dried over anhydrous sodium sulfate (Na2SO4) and adsorbed on silica gel. Initial purification was carried out using a gradient elution of dichloromethane-hexane (0 to 60%) followed by ethyl acetate-hexane (80%) to give an orange solid product (100 mg, 37% yield).
References
[1] Angewandte Chemie - International Edition, 2008, vol. 47, # 5, p. 888 - 890
[2] Patent: WO2010/132615, 2010, A1. Location in patent: Page/Page column 111
[3] Patent: WO2013/114332, 2013, A1. Location in patent: Page/Page column 92; 93
[4] Patent: US2014/371204, 2014, A1. Location in patent: Paragraph 0718
