Potassium Carbonate → HCID 67207709, compound

Participants

Reaction Conditions

Reaction Steps

(S)-(+)-2,2-Dimethyl-1,3-dioxolan-4-ylmethyl p-toluenesulfonate (286 mg, 1.0 mmol, Aldrich) and piperazine-1-carboxylic acid benzyl ester (235 mg, 1.1 mmol, Aldrich) were combined with potassium carbonate (148 g, 1.1 mmol) in dry toluene (6 mL) in a 10 mL pressure vessel. This was well stirred and heated to 127° C. for 20 h. The reaction was cooled, diluted with ethyl ether (20 mL) and 20 mL of water. The organics were washed with water, brine, dried (MgSO4) and evaporated to give 4-(S)-(−)-(2,2-dimethyl-[1,3]dioxolan-4-ylmethyl)-piperazine-1-carboxylic acid benzyl ester as a heavy oil which was purified by flash column chromatography (silica gel, eluting with 3% triethylamine and 1:1 ethyl acetate:hexane to ethyl acetate). LR-MS: 334 [(M+H)+].4-(S)-(−)-(2,2-dimethyl-[1,3]dioxolan-4-ylmethyl)-piperazine-1-carboxylic acid benzyl ester (220 mg, 0.65 mmol) was dissolved in 20 mL of ethanol and 10% palladium on carbon (50 mg, Aldrich). The mixture was hydrogenated in a Parr reactor at 40 psi for 18 h. The reaction mixture was filtered through Celite and evaporated to give an oil. The oil was mostly dissolved in hexane, treated with Norite, filtered and crystallized from cold hexane to give 1-(S)-(−)-(2,2-dimethyl-[1,3]dioxolan-4-ylmethyl)-piperazine. LR-MS: 200 [(M+H)+].

Provenance & Evidence