Hexahydropyrazolo[1,2-a]pyrazole → 1-[2-[4-(2-Ethoxycarbonylethyl)phenyl]ethyl]-1,5-diazacyclooctane

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Reaction Steps

To a solution of 2-[4-[(E)-2-ethoxycarbonylvinyl]phenyl]ethyl bromide (2.10 g) in diethyl ether (20 ml) was added 1,5-diazabicyclo[3,3,0]octane (0.89 g), and the mixture was stirred at room temperature for 16 hours. The solvent was removed under reduced pressure. To a solution of the residue in ethanol (30 ml) was added a 10% palladium on activated carbon (0.44 g), and the mixture was stirred at room temperature for 5 hours under an atmosphere of hydrogen. The catalyst was removed by filtration through a celite column, and the filtrate was concentrated under reduced pressure. The residue was quenched with an aqueous 1N-NaOH solution (20 ml), and the mixture was extracted with methylene chloride (30 ml). The extract was dried over anhydrous MgSO4, and concentrated to dryness under reduced pressure to give 1-[2-[4-(2-ethoxycarbonylethyl)phenyl]ethyl]-1,5-diazacyclooctane (2.46 g) as a colorless oily liquid.

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