ChemicalBook CAS DataBase List 6-Chloronicotinic acid

6-Chloronicotinic acid synthesis

10synthesis methods

Product Name:6-Chloronicotinic acid
CAS Number:5326-23-8
Molecular formula:C6H4ClNO2
Molecular Weight:157.55

In a 1000ml flask, add 450g chlorobenzene, 100g 2-chloro-5-methylpyridine, and 3g catalyst cobalt acetate under stirring, heat the system to 80℃, introduce oxygen, and control the oxygen flow rate at 0.4L/min. React under this condition for 4 hours. After the reaction, cool the system to room temperature, filter, and dry to obtain a mixture of 119g 6-chloronicotinic acid and cobalt acetate. Place those mentioned above mixed crude product in a 1000ml flask, add 600g of recrystallization solvent methanol, stir and heat to reflux; wait for the 6-chloronicotinic acid crude product to dissolve completely, keep warm for 5min, slowly cool the system to 5℃, precipitate a white product, maintain this internal temperature and continue stirring for 1 hour, filter, wash the filter cake once with a small amount of cooled methanol, and dry the obtained damp product at 80℃ for 4 hours to obtain 98.5g 6-chloronicotinic acid, purity 99.52% (HPLC), yield 79.7%.

5006-66-6 Synthesis

5006-66-6
468 suppliers
$13.43/1gm:

5326-23-8
557 suppliers
$5.00/1g

Yield:5326-23-8 98%

Reaction Conditions:

with hydrogenchloride; pH=2pH-value;

Steps:

2e Example 2
(e) after the amination reaction in the step (d) is completed, the amination reaction liquid is transferred to the acidification kettle,The pH of the ammoniated reaction solution is adjusted to 2 with hydrochloric acid; _:(f) crystallizing the ammoniated reaction solution after the pH value is adjusted in the step (e) for 12 hours,Then centrifugedThe resulting solid was vacuum dried,Get 6-hydroxynicotinic acid;(f-1) The 6-hydroxynicotinic acid obtained in step (f) was dissolved in anhydrous methanol and refluxed for 4h,6-hydroxy nicotinic acid and anhydrous methanol mass ratio of 1: 4,The reflux temperature was 55 ° C,After the reflux reaction cooling crystallization 13h,Then centrifugedThe resulting solid was filtered to give purified 6-hydroxynicotinic acid; _:(g) The 6-hydroxynicotinic acid obtained in the previous step was dissolved in triethylamine,Then dropping phosphorus oxychloride reflux reaction 8h,The mass ratio of triethylamine to 6-hydroxynicotinic acid and phosphorus oxychloride is 1: 2: 2.15,The dropping rate of phosphorus oxychloride is 40g / min; _:(h) After the reflux reaction is completed in step (g)The reaction solution was added to 2 ° C ice water,The reaction solution was adjusted to pH 2 with hydrochloric acid,Wherein the volume ratio of the reaction solution and ice water is 1: 7; _:(i) cooling the reaction solution after adjusting pH in step (h) for 17 h,The centrifuged solid was then crude 6-chloronicotinic acid.

References:

Anhui Xingyu Chemical Co., Ltd.;Zhang Kuanyu;Jin Wenyi;Ding Liang;Liu Guofei;Zhang Sheng CN104387317, 2017, B Location in patent:Paragraph 0035; 0039-0092

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