Diisopropylethylamine → 1-benzyl-4-[(1-cyclohexyl-3,4-dihydroisoquinolin-2(1H)-yl)carbonyl]piperidin-4-ol

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Reaction Steps

1-benzyl-4-hydroxypiperidine-4-carboxylic acid (951 mg) was dissolved in DMF (25 mL), and N,N′-carbonyldiimidazole (720 mg) was added thereto, followed by stirring at room temperature for 18 hours. Thereafter, N,N-diisopropylethylamine (784 mg) and 1-cyclohexyl-1,2,3,4-tetrahydroisoquinoline hydrochloride (1.22 g) were added to the reaction liquid, followed by stirring at 60° C. for 18 hours. The solvent was evaporated, and water and EtOAc were added to the reaction liquid. The resulting insoluble materials were separated through celite, extracted with EtOAc and dried over magnesium sulfate, and the solvent was evaporated. The resulting residue was purified by silica gel column chromatography (chloroform-MeOH) and dissolved in 1,4-dioxane (12 mL), and di-tert-butyl dicarbonate (1.3 g) was added thereto, followed by stirring at room temperature for 1 hour. The solvent was evaporated and the resulting residue was purified by silica gel column chromatography (hexane-EtOAc and then chloroform-MeOH) to obtain 1-benzyl-4-[(1-cyclohexyl-3,4-dihydroisoquinolin-2(1H)-yl)carbonyl]piperidin-4-ol (115 mg).

Provenance & Evidence