Acetic Acid → 2(1H)-Isoquinolinecarboxylic acid, octahydro-4-[(2,2,2-trifluoroacetyl)amino]-, 1,1-dimethylethyl ester

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Reaction Conditions

Reaction Steps

A solution of 2,2,2-trifluoro-N-isoquinolin-4-ylacetamide (1.57 g) and platinum oxide (150 mg) in acetic acid (25 ml) was subjected to hydrogenation (5 atm) at 60° C. for 8 hr. The catalyst was filtered off, and the filtrate was evaporated under reduced pressure. The residue was neutralized with saturated aqueous sodium hydrogen carbonate, and evaporated under reduced pressure. The residue was extracted with THF (30 ml×2), and the extract was dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure. THF (25 ml) and diisopropylethylamine (1 g) were added to the residue, and the mixture was cooled to 0 to 5° C. Di-tert-butyl dicarbonate (1.42 g) was added and the mixture was stirred at room temperature for 15 hr. The solvent was evaporated under reduced pressure, and ethyl acetate (50 ml) was added to the residue. Insoluble material was filtered off, and the filtrate was concentrated under reduced pressure. The residue was subjected to silica gel column chromatography, and the fraction eluted with hexane-ethyl acetate (9:1-7:3) was concentrated under reduced pressure to give the object compound (1.8 g) as an oil.

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