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ChemicalBook CAS DataBase List 4-amino-5-chloro-2,3-dihydrobenzofuran-7-carboxylic acid
123654-26-2

4-amino-5-chloro-2,3-dihydrobenzofuran-7-carboxylic acid synthesis

10synthesis methods
Firstly, adding methyl 4-(acetyl amino)-2-hydroxy-3-(2-hydroxy ethyl) benzoate into an organic solvent, adding triphenylphosphine and azo dioctyl phthalate diethyl ester, performing cyclization to obtain a methyl 4-acetamido-2,3-dihydro benzofuran-7-formate rough product, directly chloridizing the rough product by using N-chloro succinimide to obtain a rough product methyl 4-acetamide amino-5-chloro-7-benzofuran formate, and performing hydrolysis and purification to obtain a 4-amino-5-chloro-2,3-dihydrobenzofuran-7-carboxylic acid pure product.
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Yield:123654-26-2 89.8%

Reaction Conditions:

with 1-methoxy-2-propanol;water;sodium hydroxide at 90; for 8 h;

Steps:

7 Example 7 Synthesis of 4-amino-5-chloro-2,3-dihydrobenzofuran-7-carboxylic acid

The resulting intermediate 7 (30 g, 0.11 mol), water (150 mL),Propylene glycol monomethyl ether (36mL) and 50% sodium hydroxide solution (90mL), slowly heated to 90 ° C with stirring, the same temperature for 8h, the reaction was monitored by TLC. After the reaction is completed,Cooled to 5 ° C with ice bath and stirred for 2h, filtered with suction,The filter cake was washed with an appropriate amount of water added to 500mL single-necked flask,Water (210 mL) and propylene glycol monomethyl ether (35 mL) were added,The temperature of the reaction solution was raised to 80 ° C and the reaction solution became homogeneous.Dilute dilute hydrochloric acid, adjust pH to about 3, precipitated solid.After cooling to 10 ° C, stirring was continued for 2h. Suction filtration,The filter cake was washed with an appropriate amount of water and dried to give an off-white solid,Yield 20.8g, yield 89.8%, purity 99%

References:

CN107337658,2017,A Location in patent:Paragraph 0051; 0052

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