Ammonium Chloride → 1-cyano-3-ethyl-8-[2-(3-fluoro-4-trifluoromethyl-phenyl)-ethyl]-5,6-dihydro-8H-imidazo[1,5-a]pyrazine-7-carboxylic acid tert-butyl ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A cooled (−78° C.) solution of 3-ethyl-8-[2-(3-fluoro-4-trifluoromethyl-phenyl)-ethyl]-1-iodo-5,6-dihydro-8H-imidazo[1,5-a]pyrazine-7-carboxylic acid tert-butyl ester (1.040 g; 1.833 mmol) in anhydrous THF (50 ml) was treated dropwise with 1.6M n-BuLi in hexanes (1.6 ml; 2.560 mmol). The resulting reaction mixture was further stirred at −78° C., under nitrogen, for 3 min., and a solution of para-toluenesulfonyl cyanide (0.576 g; 3.025 mmol) in anhydrous THF (5 ml) was then added dropwise. Stirring at −78° C. was continued for 20 min. before aq. sat. NH4Cl (2 ml) was added. The resulting mixture was allowed to warm-up to rt, and water (50 ml), followed by ether (50 ml) were added. The organic layer was dried over anh. MgSO4, filtered, and concentrated to dryness under reduced pressure. Purification by FC (DCM/MeOH, 25/1) afforded 1-cyano-3-ethyl-8-[2-(3-fluoro-4-trifluoromethyl-phenyl)-ethyl]-5,6-dihydro-8H-imidazo[1,5-a]pyrazine-7-carboxylic acid tert-butyl ester as a pale yellow solid (0.233 g; 27%). LC-MS: tR=1.12 min.; [M+H]+=467.23 g/mol.

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