N-bromobutanimide → 5-Bromo-1-cyclohexylmethyl-2-methyl-6-oxo-1,6-dihydro-pyridine-3-carboxylic acid methyl ester

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Reaction Steps

MeOH (200 mL) was added to a flask containing 4-[1-(cyclohexylmethyl-amino)-ethylidene]-pent-2-enedioic acid dimethyl ester (6.3 g, 21.4 mmol). NaOMe solution (4.9 mL, 21.4 mmol, 4.375 M in MeOH) and N-bromosuccinimide (4.56 g, 25.6 mmol) were added, and the resulting mixture was refluxed for 1 h. After cooling to r.t., the solvent was evaporated in vacuo. Saturated NH4Cl was added, and the resulting mixture was extracted with CH2Cl2. The organic layer was dried over MgSO4 and concentrated. The crude product was chromatographed (20% EtOAc/hexanes) to give 4.95 g of the title compound. MS: (+) m/z 364.21, 366.16 (M+Na, 79/81Br).

Provenance & Evidence