Sulfuric Acid → 5-([1,1'-Biphenyl]-4-ylmethyl)pyrrolidin-2-one

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Reaction Conditions

Reaction Steps

A mixture of 26.5 g (100 mmol) (R/S)-5-(biphenyl-4-carbonyl)pyrrolidin-2-one, 3.0 g Pd/C (10% PD CP 4505 D/R Catalyst, BASF), 5 g conc. H2SO4 in 300 ml THF and 300 ml MeOH are hydrogenated at 1 atm pressure and heated at 50° C. After 10 h the hydrogen uptake stops. The catalyst is filtered off, washed with methanol and the resulting filtrate is concentrated in vacuo. The evaporation residue is dissolved in toluene and is washed with aqueous Na2CO3 solution. A part of the product precipitates and is filtered and dried in vacuo (96.5% HPLC area %). The toluene phase is washed twice with H2O and evaporated completely, to yield further crude product. This further crude product is purified over silica gel chromatography with toluene/methanol=4:1, to yield the product. This product is stirred in 70 ml toluene at 60° C. for 2 h. Then 70 ml heptanes fraction are added and the precipitate is filtered. The precipitate is dried in vacuo to yield (R/S)-5-biphenyl-4-ylmethylpyrrolidin-2-one (96.5% HPLC area %). 1H NMR (DMSO): 1.69 (1H), 1.96-2.05 (2H), 2.67 (1H), 2.84 (1H), 3.80 (1H), 7.31 (2H), 7.44 (2H), 7.57 (2H), 7.63 (2H), 7.74 (1H).

Provenance & Evidence