Hydrochloric Acid → [(1S)-1-[3-(Cyclopropylmethoxy)-4-(difluoromethoxy)phenyl]-2-(3,5-dichloro-1-oxido-pyridin-1-ium-4-yl)ethyl](2S)-3-[3-[[3-[(N-[(3R)-quinuclidin-3-yl]oxycarbonylanilino)methyl]phenoxy]methyl]benzoyl]thiazolidine-2-carboxylate

Participants

Reaction Steps

A solution of methyl 4-[[3-[(N-[(3R)-quinuclidin-3-yl]oxycarbonylanilino)-methyl]phenoxy]methyl]benzoate (Intermediate 5 above described) (419 mg, 0.84 mmol) in THF (2 mL) and methanol (2 mL) was added with an aqueous solution of 1N lithium hydroxide (1.7 mL, 1.68 mmol). The reaction was stirred at room temperature for 18 hours. The mixture was cooled to 0° C. and acidified by addition of 2 N hydrochloric acid dropwise to pH≈2-3. The mixture was allowed to warm to room temperature and the solvent removed in vacuo and azeotroped with toluene to dryness. This crude material was dissolved in DMF (5 mL) and ⅓ of the solution was used in the next step. [(1S)-1-[3-(cyclopropylmethoxy)-4-(difluoromethoxy)phenyl]-2-(3,5-dichloro-1-oxido-pyridin-1-ium-4-yl)ethyl](2S)-thiazolidine-2-carboxylate hydrochloride (Intermediate 9 above described) (142 mg, 0.25 mmol), 4-(dimethylamino)pyridine (13 mg, 0.11 mmol) followed by N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (81 mg, 0.42 mmol) were added and the reaction mixture was stirred at room temperature for 18 hours. Additional amounts of [(1S)-1-[3-(cyclopropylmethoxy)-4-(difluoromethoxy)-phenyl]-2-(3,5-dichloro-1-oxido-pyridin-1-ium-4-yl)ethyl](2S)-thiazolidine-2-carboxylate hydrochloride (140 mg, 0.25 mmol), N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (81 mg, 0.42 mmol) and 4-(dimethylamino)pyridine (13 mg, 0.11 mmol) were added to the reaction mixture and was stirred at room temperature for a further 18 hours. The solvent was removed in vacuo and the residue was partitioned between EtOAc (50 mL) and water. The organic phase was dried over MgSO4, filtered and the solvent was removed in vacuo. The residue was purified by preparative HPLC to yield the title compound as white solid (16 mg, 8% yield over two steps).

Provenance & Evidence