1,3-Dibromo-5,5-dimethylhydantoin → 4-Bromomethylphenyl 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranoside
Reaktionsgleichung
[C:1]([O:4][C@@H:5]1[C@@H:18]([O:19][C:20](=[O:22])[CH3:21])[C@@H:17]([O:23][C:24](=[O:26])[CH3:25])[C@@H:16]([CH2:27][O:28][C:29](=[O:31])[CH3:30])[O:15][C@@H:6]1[O:7][C:8]1[CH:13]=[CH:12][C:11]([CH3:14])=[CH:10][CH:9]=1)(=[O:3])[CH3:2].[Br:32]N1C(C)(C)C(=O)N(Br)[C:34]1=[O:35]>>[C:1]([O:4][C@@H:5]1[C@@H:18]([O:19][C:20](=[O:22])[CH3:21])[C@@H:17]([O:23][C:24](=[O:26])[CH3:25])[C@@H:16]([CH2:27][O:28][C:29](=[O:31])[CH3:30])[O:15][C@@H:6]1[O:7][C:8]1[CH:9]=[CH:10][C:11]([CH2:14][Br:32])=[CH:12][CH:13]=1)(=[O:3])[CH3:2].[CH3:34][OH:35]Komponenten
4
Versuchsvorschrift
1.4 g (3.2 mmoles) of 4-methylphenyl 2,3,4,6-tetra-O-acetyl-α-D-galactopyranoside (71) and 0.46 g (1.6 mmole) of 1,3-dibromo 5,5-dimethylhydantoine are added in 100 ml of carbone tetrachloride, and the mixture est refluxed under irradiation with light (1 000 W) for 15 minutes. After cooling, the reaction medium is filtered and the filtrate is then evaporated to dryness. 3.5 g of 4-bromomethylphenyl 2,3,4,6-tetra-O-acetyl-α-D-galactopyranoside (72) are isolated by crystallization from methanol (yield=76%).