Sodium cyanoborohydride → ethyl 1-[2-(N-benzyloxycarbonyl-N-methylamino)ethyl]4-piperidinylideneacetate

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Reaction Steps

To a stirred solution of 2-(N-benzyloxycarbonyl-N-methylamino)acetaldehyde (2.07 g, 10.0 mmol) and ethyl 4-piperidinylideneacetate (1.69 g, 10.0 mmol) in MeOH—AcOH (10:1, v/v, 22 ml) was added NaBH3CN (1.32 g, 20 mmol) and the stirring was continued overnight. The mixture was quenched by addition of sat. NaHCO3 (200 ml) and extracted with CHCl3 (3×150 ml). The combined extracts were dried over MgSO4 and evaporated. The residue was chromatographed on silica-gel with CHCl3—EtOH (40:1, v/v) to give ethyl 1-[2-(N-benzyloxycarbonyl-N-methylamino)ethyl]4-piperidinylideneacetate (1.71 g, 47%) as a colorless oil. 1H-NMR (CDCl3) δ1.25 (t, J=7.3 Hz, 3 H), 2.16 (m, 2 H), 2.57 (m, 4 H), 2.95 (m, 7 H), 3.44 (m, 2 H), 4.13 (q, J=7.3 Hz, 2 H), 5.12 (s, 2 H), 5.49-5.53 (m, 1 H), 7.35 (m, 5 H).

Provenance & Evidence