反应详情

To a solution of 4-Oxo-5,6,7,8-tetrahydro-4H-cyclohepta[b]pyrrole1,3-dicarboxylic acid 3-methyl ester 1-tert-butyl ester(l.1 g, 3.6 mmol) in DMSO(20 mL) is added 1,3-dibromo-5,5-dimethylhydantoin(1.5 g, 5.4 mmol) portion wise with the aid of a cooling bath and the resulting mixture is stirred for 18 h at RT. Water is added and the reaction mixture is extracted with ether . The combined ether layers are washed with saturated brine, dried over Na2SO4, and concentrated in vacuo. The residue is purified by flash chromatography on silica gel (10% EtOAc/Hex to 25% EtOAc/Hex) to yield 915 mg of 5-Bromo-4-oxo-5,6,7,8-tetrahydro-4H-cyclohepta[b]pyrrole-1,3-dicarboxylic acid 1-tert-butyl ester 3-methyl ester as a bright yellow oil (66%). 1H NMR(CDCl3) 1.59 (s, 9H), 1.72-1.84 (m, 1H), 2.12-2.25 (m, 2H), 2.43-2.58 (m, 1H), 3.05-3.14 (m, 1H), 3.40-3.49 (m, 1H), 3.80 (s, 3H), 4.75 (m, 1H), 7.79 (s, 1H)

1. extractionthe reaction mixture is extracted with ether
2. washThe combined ether layers are washed with saturated brine
3. dry with materialdried over Na2SO4
4. concentrationconcentrated in vacuo
5. customThe residue is purified by flash chromatography on silica gel (10% EtOAc/Hex to 25% EtOAc/Hex)