Diisopropylazodicarboxylate (97 mg, 0.48 mmol) was added dropwise at r.t. to a solution of (4-chloro-2-methyl-quinolin-7-yl)-methanol (example 2c, 100 mg, 0.48 mmol), triphenylphosphine (126 mg, 0.48 mmol), 2-methoxyphenol (60 mg, 0.48 mmol) in dichloromethane (2.5 mL). After shaking 24 h at r.t., the solvent was evaporated, and the residue was taken up in pyrrolidine (1.37 g, 19.2 mmol) and shaken for 23 h at 80° C. After cooling the reaction mixture was partitioned between sat. aq. ammonium chloride solution and dichloromethane, the organic layer was washed with brine, dried (MgSO4), and evaporated. Chromatography (SiO2, dichloromethane/methanol 19:1) yielded a yellowish solid which was dissolved in ethanol and treated with 20% ethanolic oxalic acid solution. The precipitate was collected by filtration and dried to afford the title compound (90 mg, 43%). Off-white solid, ISP-MS: m/e=349.4 ([M+H—C2H2O4]+).
