반응 #1467732

반응 방정식

boron tribromide

4-Chloro-1-(4-methoxy-3-methylbenzyl)-2-phenylimidazole-5-acetic acid

→

4-chloro-1-(4-hydroxy-3-methylbenzyl)-2-phenylimidazole-5-acetic acid

수율 75.6%

용매

dichloromethane

dichloromethane

반응 조건

후처리

1. 1
   workup.ADDITIONwas added dropwise
2. 2
   기타A precipitate separated out immediately
3. 3
   workup.DISSOLUTIONafter dissolution of the starting material
4. 4
   workup.STIRRINGthe precipitate was stirred with 50 ml each of ethyl acetate and water
5. 5
   세척The ethyl acetate layer was washed with water
6. 6
   기타evaporated to dryness under reduced pressure
7. 7
   세척The residue was washed with a small amount of acetone
8. 8
   기타recrystallized from aqueous alcohl

실험 절차

4-Chloro-1-(4-methoxy-3-methylbenzyl)-2-phenylimidazole-5-acetic acid (1.1 g) was suspended in 20 ml of dichloromethane and 4 ml of a dichloromethane solution containing 1 g of boron tribromide was added dropwise under stirring at room temperature. A precipitate separated out immediately after dissolution of the starting material. The mixture was allowed to stand for 6 hours. The supernatant was discarded and the precipitate was stirred with 50 ml each of ethyl acetate and water. The ethyl acetate layer was washed with water and evaporated to dryness under reduced pressure. The residue was washed with a small amount of acetone and recrystallized from aqueous alcohl to give 0.8 g of 4-chloro-1-(4-hydroxy-3-methylbenzyl)-2-phenylimidazole-5-acetic acid as colorless scales, m.p. 193°-195° C. (decompn.).

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