1,1'-Carbonyldiimidazole → (3aR, 7R,7aR)-4,4-diphenyl-7-fluoro-2-[(2-pyrrolidinophenyl)acetyl]perhydroisoindole

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Reaction Steps

0.28 cm3 of triethylamine and 0.32 g of carbonyldiimidazole are added to a solution, cooled to 4° C., of 0.57 g of the hydrobromide salt of (2-pyrrolidinophenyl)acetic acid in 20 cm3 of dry dichloromethane. The mixture is stirred for one hour at +4° C. and then a solution of 0.67 g of (3aR,7R,7aR)-4,4-diphenyl-7-fluoroperhydroisoindole hydrochloride in 20 cm3 of dry dichloromethane and 0.28 cm3 of triethylamine, is added. The reaction mixture is stirred at room temperature for 24 hours and then diluted with 100 cm3 of dichloromethane, washed twice with 50 cm3 of water, dried over magnesium sulphate, filtered and concentrated to dryness under reduced pressure (2.7 kPa). The residue is chromatographed on a silica gel column (particle size 0.04-0.06 mm, diameter 3.5 cm, height 38 cm), eluting under a nitrogen pressure of 0.5 bar with a cyclohexane and ethyl acetate mixture (70/30 by volume) and collecting fractions of 20 cm3. Fractions 26 to 54 are pooled and concentrated to dryness under reduced pressure (2.7 kPa). The residue is crystallized from an acetonitrile and diisopropyl oxide mixture (25/75 by volume). 0.16 g of (3aR,7R,7aR)-4,4-diphenyl-7-fluoro-2-[(2-pyrrolidinophenyl)acetyl]perhydroisoindole is obtained in the form of white crystals; melting point 170° C.

Provenance & Evidence