Hydrochloric Acid → 8-(2-[1,3]Dioxolan-2-yl-ethyl)-4-(4-fluorobenzyl)-3-(4-isobutoxybenzyl)-1-oxa-3.8-diaza-spiro[4.5]decan-2-one, hydrochloride

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Reaction Conditions

Reaction Steps

69NLS77 (300 mg, 0.57 mmol) was N-BOC deprotected by treatment with a solution of TFA (2 mL) in dichlornethane (2 mL) at rt for 1.5 h. The solvent was removed in vacuo, the residue coevaporated twice with acetonitrile and redissolved in the same solvent (10 mL). Potassium carbonate (110 mg, 0.80 mmol) and 2-(2-bromoethyl) 1,3-dioxolane (80 μL, 0.68 mmol) were added, followed by sodium iodide (102 mg, 0.68 mmol) and the mixture stirred for 3 days at 50° C. Partitioning of the mixture between water and dichloromethane, extraction of the aqueous layer twice with dichloromethane, drying of the combined organic layers over Na2SO4, filtering and evaporation of the solvent gave crude 69NLS79-II. The residue was purified by silica gel column chromatography, eluting with a stepwise gradient of 0-4% methanol in dichloromethane, affording 69NLS79-II (127 mg, 0.24 mmol) as a colorless oil. The compound was converted to its HCl form by treatment with 2M HCl in diethylether as described above for 69NLS75, giving the salt as a colorless powder.

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