C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.[Br:20]N1C(=O)CCC1=O.O[C:29]1[CH:34]=[CH:33][N:32]=[C:31]([S:35][CH2:36][C:37]([O:39][CH2:40][CH3:41])=[O:38])[N:30]=1.O>O1CCOCC1>[Br:20][C:29]1[CH:34]=[CH:33][N:32]=[C:31]([S:35][CH2:36][C:37]([O:39][CH2:40][CH3:41])=[O:38])[N:30]=1Under argon, 52.5 g (0.20 mol) of triphenylphosphine are initially charged in 600 ml of dioxane, and 35.6 g (0.20 mol) of N-bromosuccinimide are added a little at a time, with cooling. The mixture is stirred at RT for 30 min. 8.6 g (0.04 mol) of ethyl [(4-hydroxy-2-pyrimidinyl)thio]acetate are then added and the mixture is heated at reflux for 45 min. A total of 2 l of water are added to the mixture, which is then extracted 3× with in each case 300 ml of methyl tert-butyl ketone. The organic phase is washed 2× with water and 1× with concentrated NaCl solution, dried over magnesium sulphate and concentrated. The residue is stirred in 60 ml of methyl tert-butyl ketone and filtered off. The mother liquor is concentrated and the residue is purified by silica gel chromatography (dichloromethane).
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