To a suspension of sodium hydride (0.05 g, 1.2 mmol, 60% dispersion in oil, pre-washed with hexane) in N,N-dimethylformamide (3 mL) was added a solution of 5-pyridin-3-yl-1,3-dihydro-2H-indol-2-one (0.19 g, 0.90 mmol) in N,N-dimethylformamide (4 mL). The mixture was stirred for 20 min under nitrogen atmosphere. 2-Chloro-5-(morpholin-4-ylmethyl)pyridine 1-oxide (0.14 g, 0.60 mmol), dissolved in N,N-dimethylformamide (3 mL) was added dropwise and the mixture was stirred at room temperature for 2 h and then heated at 130° C. for 1.5 h. The solvent was evaporated in vacuo and the residue was partitioned between 2 M HCl and ethyl acetate and the phases were separated. The aqueous layer was alkalized by addition of NaHCO3 (s) and extracted with ethyl acetate. The organic layer was dried (Na2SO4) and the solvent was removed in vacuo affording 200 mg of the title compound as a yellow solid: MS (ES) m/z 403 (M++1).
