L-Proline → 3-(6,7,8,9-Tetrahydro-benzo[b]-[1,8]naphthyridin-8-yl)-propionic acid ethyl ester

Participants

Reaction Steps

A solution of 2-amino-pyridine-3-carbaldehyde (1-3) (0. 244 g, 2.0 mmol) and 3-(3-oxo-cyclohexyl)-propionic acid ethyl ester (14-1) (0.245 g, 2.00 mmol; for prep., see J. R. Wiseman et.al., J. Am. Chem. Soc., 1970, 92, 956-962) in ethanol (10 mL) was treated with L-proline (0.230 g, 2.00 mmol) and heated at reflux for 12 h. The solution was cooled to ambient temperature and concentrated. The residue was purified by flash chromatography (10% acetone in CH2Cl2) to give 14-2.

Provenance & Evidence