p-Xylyl bromide → [1-(4-Methyl-benzyl)-2,5-dioxo-imidazolidin-4-yl]-acetic acid methyl ester

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Reaction Steps

A solution of (2,5-dioxo-imidazolidin-4-yl)-acetic acid, methyl ester (2.35 g, 13.7 mmol) in DMF (100 mL) is treated with p-methyl benzyl bromide (2.90 g, 15.7 mmol), MgSO4 (3.30 g, 27.4 mmol) and then K2CO3 (3.77 g, 27.3 mmol). The resultant mixture is stirred under N2 in an ice bath for 30 minutes and then warmed to room temperature for 16 h. The reaction mixture is then filtered, and then aqueous 1N HCl (150 mL) is added to the filtrate. The filtrate is extracted with EtOAc and the organic layer dried. The solvent is removed to give 4.11 g crude product which is purified by flash chromatography using 100% CH2Cl2 then 97.5:2.5 CH2Cl2:MeOH to give 3.67 g (97%) [1-(4-methyl-benzyl)-2,5-dioxo-imidazolidin-4-yl]-acetic acid methyl ester. 1H NMR. MS (ES+) Calc'd for C14H17N2O4 (M+1) 277. Found m/z 277 (100%).

Provenance & Evidence