Dimethylformamide dimethyl acetal → tert-butyl 3-[(dimethylamino)methylene]-4-oxotetrahydro-1(2H)-pyridinecarboxylate

Participants

Reaction Conditions

Reaction Steps

tert-Butyl-4-oxo-1-piperidinecarboxylate (10 g, 50 mmol) and N,N-dimethylformamide dimethyl acetal (7.3 ml, 55 mmol) are added to dry DMF (75 ml) under nitrogen and the mixture is heated at 90° C. for 16 hr. The reaction mixture is concentrated under reduced pressure, and the residue is partitioned between EtOAc (200 ml) and brine (200 ml). Layers are separated and the aqueous phase is extracted with EtOAc (200 ml). The combined organic extracts are dried over sodium sulfate and concentrated under reduced pressure to give a brown oil that solidifies on standing. The material is used for the next step reaction without further purification. 1H NMR (300 MHz, CDCl3) δ 7.44 (1H, s), 4.54 (2H, s), 3.59 (2H, t), 3.06 (6H, s), 2.42 (2H, t), 1.44 (9H, s); MS (+VE) m/z 255.1 (M++1).

Provenance & Evidence