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ChemicalBook CAS DataBase List 4-Hydroxyphenylacetic acid
156-38-7

4-Hydroxyphenylacetic acid synthesis

10synthesis methods
4-Hydroxyphenylacetic acid is synthesized by diazotization and hydrolysis of 4-aminophenylacetic acid.
4-aminophenylacetic acid and alkali solution are prepared into sodium salt, and then sulfuric acid is added. Cool to 0°C, control the temperature at 0-5°C, and add sodium nitrate solution dropwise, and the reaction is completed for 0.5h. The obtained diazonium was added dropwise to dilute sulfuric acid at 90-95°C for about 1 hour, and the reaction was continued for 1 hour. The reaction solution was decolorized and filtered, cooled and extracted with ethyl acetate, and the extract was recovered with ethyl acetate to obtain 4-Hydroxyphenylacetic acid. The yield is about 85%.
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Yield:156-38-7 99%

Reaction Conditions:

with boron tribromide in dichloromethane at -78 - -15; for 4 h;Inert atmosphere;

Steps:

2-(4-Hydroxyphenyl)acetic Acid (13)
2-(4-Hydroxyphenyl)acetic acid (13) was prepared according to a literature protocol.18 To a cooled (–78 °C), stirred solution of 2-(4-methoxyphenyl)acetic acid (1.0 g, 5.08 mmol, 1 equiv) in CH2Cl2 (10 mL)was added BBr3 (12 mL, 1 M in CH2Cl2) under an inert atmosphere. The reaction was then allowed to stir over 4 h whilst warming from –78 °C to –15 °C. After complete conversion of the starting material, the reaction mixture was quenched by adding H2O (15 mL) and the aqueous layer was extracted with CH2Cl2 (3 × 20 mL). The combined organic layers were washed with brine, dried over Na2SO4 and concentrated. The obtained white solid was dried in a desiccator for 1 d to give 13 (0.90 g, 99percent). Mp 137–140 °C; Rf = 0.5 (5percent MeOH/CH2Cl2).

References:

Hussain, Mulla Althafh;Khan, Faiz Ahmed;Shashi, Shashi [Synthesis,2019,vol. 51,# 24,p. 4601 - 4610]

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