p-Toluenesulfonic acid → tert-Butyl 2-bromo-7,9-dimethyl-5,7,8,9-tetrahydro-6H-pyrido[3',4':4,5]pyrrolo[2,3-b]pyridine-6-carboxylate

Participants

Reaction Conditions

Reaction Steps

2-Bromo-6-(1-methylhydrazinyl)pyridine (1.60 g, 7.98 mmol) and tert-butyl 2-methyl-4-oxopiperidine-1-carboxylate (enantiomer B) (1.70 g, 7.98 mmol) were heated in EtOH (10 mL) at reflux for 16 h and then the mixture was concentrated to provide a white foam. This foam was combined with para-toluenesulphonic acid (3.18 g, 16.7 mmol) and heated to 160° C. for 10 minutes. The mixture was allowed to cool and isopropanol (20 mL), water (8 mL), potassium carbonate (5.00 g, 36.2 mmol), and di-tert-butyl dicarbonate (2.55 g, 11.7 mmol) were added. After stirring for 16 h, the mixture was partitioned between methylene chloride and water, and the organic layer was removed, dried, and concentrated. The residue was purified by column chromatography eluting with ethyl acetate/hexanes (1:4) to provide the title compound (360 mg, 11%) as a white solid: ESI MS m/z 380 [M+H]+.

Provenance & Evidence