Stannous chloride dihydrate → (+/-)-(4R*,5R*)-5-[(1S*)-hydroxy(5-phenyl(2-thienyl))methyl]-4-(4-aminophenyl)-1-methylpyrrolidin-2-one

Participants

Reaction Conditions

Reaction Steps

The ester of Intermediate U step 1 was reduced with lithium triethylborohydride using the procedure described as Method 2 in the preparation of Intermediate T. The resulting alcohol was then subjected to Swern oxidation using the procedure described as Method 1 in the preparation of Intermediate Z, followed by a reaction of the resulting aldehyde with 2-phenylthiophene and n-BuLi in a manner analogous to that of Example 3a. To the resulting product, (±)-(4R*,5R*)-5-[(1S*)-hydroxy(5-phenyl(2-thienyl))methyl]-4-(4-nitrophenyl)-1-methylpyrrolidin-2-one (110 mg, 0.27 mmol), in EtOH (10 mL) was added tin(II) chloride dihydrate (312 mg, 1.38 mmol, 5 equiv), and the resulting mixture was heated at 70° C. for 2.5 h, then allowed to cool to room temperature and poured onto ice water. A saturated NaHCO3 solution was added to adjust the mixture to pH 8. The basic mixture was extracted with EtOAc, dried (MgSO4) and concentrated under reduced pressure. The crude product was purified by flash chromatography (EtOAc) to give (±)-(4R*,5R*)-5-[(1S*)-hydroxy(5-phenyl(2-thienyl))methyl]-4-(4-aminophenyl)-1-methylpyrrolidin-2-one (63 mg, 60%) as a yellow solid: mp 221-222° C.; TLC (EtOAc) Rf 0.40; HPLC ES-MS m/z (rel abundance) 379 (MH+, 100%).

Provenance & Evidence