Sulfuric acid magnesium salt (1:1) → 4'-[(4-{4-[1-(1-Formylcyclobutyl)ethoxy]cyclohexyl}-5-oxo-7-propyl-4,5-dihydro[1,2,4]triazolo[1,5-a]pyrimidin-6-yl)methyl]biphenyl-2-carbonitrile

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Reaction Steps

A mixture of 4′-{[4-(5-methyl-6,13-dioxadispiro[3.2.5.2]tetradec-10-yl)-5-oxo-7-propyl-4,5-dihydro[1,2,4]triazolo[1,5-a]pyrimidin-6-yl]methyl}biphenyl-2-carbonitrile (15.33 g), sodium cyanotrihydroborate (7.01 g), anhydrous magnesium sulfate (12.76 g) and tetrahydrofuran (330 mL) was stirred at room temperature for 10 min. Then, boron trifluoride-diethyl ether complex (13.4 mL) was added dropwise, and the mixture was stirred under an argon atmosphere at 50° C. for 8 hr. The reaction mixture was cooled to room temperature, saturated aqueous sodium hydrogen carbonate solution was added, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure. To a solution of the obtained residue in acetonitrile (300 mL) was added 1,1,1-triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1H)-one (1.64 g) under ice-cooling, and the mixture was stirred at room temperature for 15 hr. The reaction mixture was diluted with saturated aqueous sodium hydrogen carbonate solution, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure, and the residue was purified by silica gel chromatography [eluent: hexane/ethyl acetate=80/20→50/50 (volume ratio)] to give the title compound as a colorless amorphous compound (7.21 g, 47%).

Provenance & Evidence