Triethylamine → (+)-(1R,3R)-4-[3-(tert-butyl-dimethyl-silanyloxy)-cyclopentylamino]-2-methylsulfanyl-pyrimidine-5-carboxylic acid ethyl ester

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Reaction Steps

To a solution of (−)-(1R,3R)-(3-azido-cyclopentyloxy)-tert-butyl-dimethyl-silane (540 mg, 2.24 mmol) (from Example 27c supra) in ethanol (30 mL) was added platinum oxide (51 mg, 0.22 mmol) (Aldrich) and the mixture was hydrogenated under 1 atmosphere of hydrogen overnight. The mixture was then filtered, the solids were washed with tetrahydrofuran (approximately 25 mL) and the combined filtrate was concentrated to a residue that was dissolved in dioxane (50 mL). To that solution was added triethylamine (620 μL, 450 mg, 4.48 mmol) (Aldrich) and ethyl 4-chloro-2-methylthio-5-pyrimidinecarboxylate (520 mg, 2.24 mmol) (Aldrich) and the mixture was stirred at reflux for 1 hour. The reaction mixture was then cooled and partitioned between ethyl acetate and water. The ethyl acetate layer was collected, dried over sodium sulfate and concentrated to a residue that was purified by silica gel column chromatography with a 0–20% ethyl acetate in hexanes gradient to give (+)-(1R,3R)-4-[3-(tert-butyl-dimethyl-silanyloxy)-cyclopentylamino]-2-methylsulfanyl-pyrimidine-5-carboxylic acid ethyl ester as a colorless viscous oil. (Yield 710 mg, 77%).

Provenance & Evidence