反应详情

4-[2-(2-Methyl-5-oxo-4,4-diphenyl4,5-dihydro-imidazol-1-yl)-acetyl]-benzoic acid ethyl ester (540 mg, 1.2 mmol) is dissolved in 12 mL dioxane and an aqueous 2 Molar LiOH solution (920 uL, 1.8 mmol) is added drop wise. The reaction mixture is stirred at room temperature for 12 hours. Subsequently the mixture is evaporated and the residue taken up in water. The mixture is stirred and concentrated hydrochloric acid is added drop wise until a pH of 2 is reached. The precipitating crystals are filtered off, re-crystallized from methylene chloride and dried to yield 4-[2-2-methyl-5-oxo-4,4-diphenyl-4,5-dihydro-imidazol-1-yl)-acetyl]-benzoic acid (435 mg, 84%) light yellow solid. LC/MS at 254 nm; [M+H] 413; Rt 3.154 min.

1. customSubsequently the mixture is evaporated
2. stirringThe mixture is stirred
3. additionconcentrated hydrochloric acid is added drop wise until a pH of 2
4. filtrationThe precipitating crystals are filtered off
5. customre-crystallized from methylene chloride
6. customdried