反応 #1904059

反応方程式

hydrochloride

2-amino-5-bromobenzoic acid

methylmagnesium bromide

ether

sodium hydroxide

→

2-(2-amino-5-bromophenyl)propan-2-ol

収率 57.0%

溶媒

ethyl acetate

THF

反応条件

後処理

1. 1
   workup.ADDITIONwas added
2. 2
   その他The organic layer was separated
3. 3
   抽出aqueous layer was extracted with ethyl acetate (3×100 mL)
4. 4
   洗浄The combined organic layers were washed with brine
5. 5
   乾燥dried (MgSO4)
6. 6
   その他After removal of solvent in vacuo
7. 7
   その他the residue was purified by a silica gel flash chromatography (hexane:ethyl acetate/3:2)

実験手順

A solution of 2-amino-5-bromobenzoic acid (10 g, 46 mmol) in dry THF (200 mL) was treated at −78° C. under nitrogen with a solution of methylmagnesium bromide in ether (3.0 M, 90 mL, 270 mmol). The reaction mixture was slowly warmed to ambient temperature, kept stirring for 48 hours under nitrogen and then poured into a cold 0.5 N aqueous hydrochloride solution (300 mL). The mixture was neutralized with aqueous 1 N sodium hydroxide solution and ethyl acetate (300 mL) was added. The organic layer was separated and aqueous layer was extracted with ethyl acetate (3×100 mL). The combined organic layers were washed with brine and dried (MgSO4). After removal of solvent in vacuo, the residue was purified by a silica gel flash chromatography (hexane:ethyl acetate/3:2) to give 2-(2-amino-5-bromophenyl)propan-2-ol as off-white solid (6 g, 57%): mp 62-63° C.; 1H-NMR (CDCl3) δ 7.19 (d, 1H, J=2.3 Hz), 7.12 (dd, 1H, J=8.4, 2.3 Hz), 6.51 (d, 1H, J=8.4 Hz), 4.70 (s, 2H), 1.82 (s, 1H), 1.65 (s, 6H).

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