C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.O[CH2:21][CH2:22][C:23]1[CH:28]=[CH:27][C:26]([NH:29][C:30](=[O:36])[O:31][C:32]([CH3:35])([CH3:34])[CH3:33])=[CH:25][CH:24]=1.[Br:37]N1C(=O)CCC1=O>ClCCl.CCOCC>[Br:37][CH2:21][CH2:22][C:23]1[CH:28]=[CH:27][C:26]([NH:29][C:30](=[O:36])[O:31][C:32]([CH3:35])([CH3:34])[CH3:33])=[CH:25][CH:24]=18.68 g (33.08 mmol) of triphenylphosphine are added, under an argon atmosphere, to a solution of 7.85 g (33.08 mmol) of tert-butyl [4-(2-hydroxyethyl)phenyl]carbamate in 85 mL of dichloromethane. The mixture is cooled to 0° C. and 5.95 g (33.08 mmol) of N-bromosuccinimide are added portionwise over 25 minutes. Stirring is continued for 3 hours at 0° C. The solvent is then evaporated off, the oil obtained is taken up in ether and the precipitate formed is filtered off and discarded. The filtrate is evaporated and the residue is purified by chromatography on silica gel (eluent: 10/90 EtOAc/heptane) to give 6.90 g of tert-butyl [4-(2-bromoethyl)phenyl]carbamate, the characteristics of which are as follows:
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