Sodium Hydroxide → (4R,6S,E)-6-[2-[4,5-Bis(4-fluorophenyl)-2-(1-methylethyl)-1H-imidazol-1-yl]-ethenyl]-4-hydroxy-tetrahydro-2H-pyran-2-one

Participants

Reaction Steps

A solution of 1,1-dimethyleth-1-yl (3R,5S,E)-7-[4,5-bis(4-fluorophenyl)-2-(1-methylethyl)-1H-imidazol-1-yl]-3,5-dihydroxy-6-heptenoate (25.6 mg) in redistilled THF (1.4 ml) was treated with aqueous sodium hydroxide solution (0.1M, 0.5 ml) and the clear colourless solution was stirred at room temperature. After 3.5 h the reaction mixture was concentrated to ca 0.5 ml. The residue was diluted with water (3 ml), acidified to pH4 with hydrochloric acid (2M), ammonium sulphate added and then extracted with ethyl acetate (4×3 ml). The combined extracts were dried and evaporated to a white gummy solid (25 mg). This was dissolved in dry dichloromethane (1.4 ml) and then treated with 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide metho-p-toluenesulphonate (42.4 mg). The resulting solution was stirred at room temperature. After 18.5 h the reaction mixture was diluted with water (5 ml) and then extracted with dichloromethane (3×5 ml). The combined extracts were washed with brine (5 ml), dried and evaporated to a cream solid (23 mg). The solid was filtered through a short colum of 70-230 mesh silica developing and eluting with System A (3:1) to give the title compound as a cream solid (18 mg), νmax (CHBr3) 1735cm-1 (lactone), δ(CDCl3) values as for those described for the racemate obtained in Example 10.

Provenance & Evidence