Sodium Hydroxide → 1246390-08-8

Participants

Reaction Steps

In a 250 mL round bottom flask with a magnetic stirrer, 5.4 g (16.7 mmol) 4-cyclopentyl-piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-ethyl ester was dissolved in 40 mL EtOH. To the colourless solution 40 mL 4N NaOH was added. The orange solution was stirred under reflux for total of 6 days. The ethanol was removed and the reaction mixture was diluted with 100 mL ice water and extracted twice with 100 mL diethyl ether. The aqueous layer was acidified with 60 mL 4 N HCl to pH=2. A white precipitate formed and after addition of 200 mL ethyl acetate: THF 1:1 the white gelatinous suspension was filtered through a membrane filter. The aqueous layer from the filtrate was separated and extracted once with 100 mL ethyl acetate. The organic was layer dried with Na2SO4, filtered and concentrated under vacuum. The crude product (2.54 g, yellow viscous oil) was purified over silica chromatography eluting with a gradient formed from heptane and ethyl acetate to yield after evaporation of the product containing fractions 1.89 g (38%) of the title compound as off-white solid. MS ISP (m/e): 298.2 [(M+H)+].

Provenance & Evidence