HCID 131726048, compound → HCID 131726047, compound

Participants

Reaction Steps

3-(tert-Butyldimethyl-silanyloxymethyl)-pyridine-2-carboxylic acid isopropyl ester (800 mg, 2.6 mmol) was dissolved in 6 mL of methanol in a pressure hydrogenation vessel to which 100 mg of PtO2 was added (Rh on alumina may also be used). The vessel was shaken under 50 psi of hydrogen for 5 hrs. The suspension was filtered through Celite and the solution was concentrated in vacuo to provide the desired compound, cis-3-(tert-butyl-dimethyl-silanyloxymethyl)-piperidine-2-carboxylic acid isopropyl ester. MS 316 (M+1). Without further purification the product was acylated under standard conditions with 1-(4-chloro-phenyl)-cyclobutanecarbonyl chloride (itself prepared from the carboxylic acid using excess thionyl chloride at reflux for 1 hr. followed by concentration in vacuo). Water/ether extractive workup gave, after concentration of the organic layers in vacuo and chromatography on silica gel, the desired compound, cis-3-(tert-Butyl-dimethyl-silanyloxymethyl)-1-[1-(4-chloro-phenyl)-cyclobutanecarbonyl]-piperidine-2-carboxylic acid isopropyl ester (720 mg, 55% for two steps) MS 508 (M+1). The cis stereochemistry was assigned based upon a 1H NMR coupling constant of 4 Hz for the proton at C-2 of the piperidine ring.

Provenance & Evidence