Dimethylformamide → (S)-1-[(S)-1-(2,3-Dihydro-benzo[1,4]dioxin-2-yl)methyl]-3-methyl-piperidine-3-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

A mixture of (S)-ethyl-3-methylpiperidine-3-carboxylate (7.23 g, 42.2 mmol), Toluene-4-sulfonic acid (R)-1-(2,3-dihydro-benzo[1,4]dioxin-2-yl)methyl ester (15.0 g, 44.3 mmol), potassium carbonate (6.42 g, 46.4 mmol) and N,N-dimethyl formamide (50 ml) was heated to 120° C. After 4 hours the reaction mixture was cooled down, water (35 ml) was added and the mixture was extracted twice with ethyl acetate. The combined ethyl acetate layers were evaporated to dryness. Toluene (35 ml) was added to the evaporation residue and the mixture was extracted twice with 1M HCl. The combined acidic water layers were made basic with aq NaOH. The basic water layer was extracted twice with ethyl acetate and the combined ethyl acetate layers were evaporated to dryness to yield 10.8 g (76%) of the title compound.

Provenance & Evidence