Hydrochloric Acid → (3R,4R)-4-[3-(R,S)-hydroxy-3-(6-methoxyquinolin-4-yl)propyl]-1-[2-(cyclopentylthio)ethyl]piperidine-3-carboxylic acid dihydrochloride

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Reaction Conditions

Reaction Steps

2 cm3 of 5N aqueous sodium hydroxide solution were added, with stirring and under an inert atmosphere, to a solution of 0.48 g of methyl (3R,4R)-4-[3-(R,S)-hydroxy-3-(6-methoxyquinolin-4-yl)propyl]-1-[2-(cyclopentylthio)ethyl]piperidine-3-carboxylate in 10 cm3 of methanol. After heating the mixture for 16 hours at a temperature in the region of 60° C., the reaction mass was evaporated under reduced pressure (2.9 kPa) at a temperature in the region of 60° C. and the residue obtained was taken up in 4.3 cm3 of distilled water to which had been added 4.3 cm3 of 28% hydrochloric acid. The remaining insoluble material was filtered off and then the filtrate was evaporated under the same conditions as above. The residue obtained was stirred in a dichloromethane/methanol (90/10 by volume) mixture. The resulting precipitate was filtered off and washed with 3 times 2.5 cm3 of the same mixture. The filtrate was evaporated under reduced pressure (5 kPa) at a temperature in the region of 40° C. 0.48 g of (3R,4R)-4-[3-(R,S)-hydroxy-3-(6-methoxyquinolin-4-yl)propyl]-1-[2-(cyclopentylthio)ethyl]piperidine-3-carboxylic acid dihydrochloride was obtained in the form of a foam with a green color melting with softening at a temperature in the region of 156° C.

Provenance & Evidence