Water → 1-Benzyl-4-[3-(tert-butoxycarbonylamino)-1-oxocyclobutan-3-yl]-2-pyrrolidone

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Reaction Steps

A 4.89 g (13.6 mmol) portion of 1-benzyl-4-[3-(tert-butoxycarbonylamino)-1-hydroxycyclobutan-3-yl]-2-pyrrolidone was dissolved in 100 ml of dimethyl sulfoxide to which, while cooling in an ice bath with stirring, were then added 6.24 ml (44.8 mmol) of triethylamine and 6.47 g (10.7 mmol) of sulfur trioxide-pyridine complex in that order, subsequently carrying out 14 hours of stirring at room temperature. While cooling in an ice bath with stirring, the reaction solution was mixed with water and then with ethyl acetate to effect separation of layers. The organic layer was washed with saturated brine, the aqueous layer was extracted with ethyl acetate and then the organic layers were combined and dried over anhydrous sodium sulfate. After filtration, the solvent was evaporated and the resulting residue was purified by a silica gel column chromatography to give 4.69 g (96.3%) of the title compound. Thereafter, optical resolution of Isomers F1 and F2 as enantiomers originated from the pyrrolidine 4 position asymmetric carbon atom of the thus obtained compound was carried out by HPLC under the following conditions.

Provenance & Evidence