L-Proline → HCID 86758297, compound

Participants

Reaction Steps

A stirred solution of 2-amino-3-formylpyridine (341 mg, 2.80 mmol), 3-5 (900 mg, 2.15 mmol) and proline (322 mg, 2.80 mmol) in ethanol (20 mL) was heated at reflux for 4 h, and the cooled to ambient temperature. The reaction mixture was diluted with ethyl acetate, washed with saturated aqueous sodium hydrogen carbonate, saturated aqueous sodium chloride, and dried over anhydrous magnesium sulfate. The reaction mixture was filtered and concentrated at reduced pressure. The resulting oil was purified by flash column chromatography (silica gel, 3:0.3:0.3 to 8:0.8:0.8% ethanol/ammonium hydroxide/water in ethyl acetate) to give 3-6 as an inseparable mixture of diastereomers. To a stirred solution of the mixture of 3-6 in methanol (40 mL) was added a slurry of 10% palladium on carbon (150 mg) in ethanol (3 mL). The resulting suspension was stirred under a slight overpressure of hydrogen for 16 h. The reaction mixture was filtered through Celite and concentrated at reduced pressure. The resulting oil was purified by flash column chromatography (silica gel, 3:0.3:0.3 to 8:0.8:0.8% ethanol/ammonium hydroxide/water in ethyl acetate) to give 3-7 as a 2:1 mixture of diastereomers.

Provenance & Evidence