To solution of 1-(5-(1-methyl-2-oxo-1,2,3,4-tetrahydroquinolin-6-yl)pyridin-3-yl)cyclopropanecarboxylic acid (example 59 [C], 0.3 g, 0.931 mmol) in toluene (15 mL) were added TEA (0.141 g, 1.4 mmol) and diphenylphosphoryl azide (0.384 g, 1.4 mmol) and then the reaction mixture was heated to reflux for 4 h. The mixture was concentrated in vacuo, the residue was dissolved in THF (30 mL) and the solution cooled to 0° C. Then, a solution of KOtBu (0.627 g, 5.58 mmol) in THF (13 mL) was added and the mixture was stirred for 1 h at 0° C. and then over night at room temperature. The mixture was concentrated in vacuo, the residue was preadsorbed on silica gel and purified by silica gel flash chromatography eluting with a 0 to 10% MeOH-DCM gradient to give a yellow amorphous solid (0.104 g). This material was then further purified by reverse phase HPLC on a Gemini-NX column, eluting with a MeOH—H2O (0.05% TEA) gradient to give the title compound (0.02 g, 7%) as a colorless amorphous solid. MS: 292.3 (M+H+).
