To a solution of 4-nitro-1H-indazole (0.200 g, 1.23 mmol) in DMA (3 mL) was added 60% sodium hydride (0.074 g, 1.84 mmol) at ambient temperature. After 30 minutes, tert-butyl 3-(tosyloxymethyl)piperidine-1-carboxylate (0.544 g, 1.47 mmol) was added. The mixture was heated at 100° C. overnight, diluted with water, extracted with DCM, dried (phase separator silicone treated filter paper), concentrated and the residue purified on silica gel (10-50% EtOAc in DCM) to provide tert-butyl 3-((4-nitro-1H-indazol-1-yl)methyl)piperidine-1-carboxylate (0.176 g, 40% yield) as a yellow gum.
