ChemicalBook CAS DataBase List CHLOROQUINE

CHLOROQUINE synthesis

9synthesis methods

Product Name:CHLOROQUINE
CAS Number:54-05-7
Molecular formula:C18H26ClN3
Molecular Weight:319.87

Chloroquine, 7-chloro-4-(4-diethylamino-1-methylbutylamino)-quinoline (37.1.3), is made by reacting 4,7-dichloroquinoline (37.1.1.1) with 4-diethylamino- 1-methylbutylamine (37.1.1.2) at 180 °C.

In order to realize the synthesis, the necessary 4,7-dichloroquinoline (37.1.1.1) is prepared in several ways from 3-chloroaniline. One of these ways consists of reacting 3-chloroaniline with ethoxymethylenmalonic ester to make (3-choroanilino)-methylenemalonic ester (37.1.1.4), which then undergoes high-temperature heterocyclization to make the ethyl ester of 7-chloro-4-hydroxyquinolin-3-carboxylic acid (37.1.1.5). Hydrolyzing this with sodium hydroxide gives 7-chloro-4-hydroxyquinolin-3-decarboxylic acid (37.1.1.6), which when heated at 250–270 ° C is decarboxylated, forming 7-chloro-4-hydroxyquinoline (37.1.1.7). Treating this with phosphorus oxychloride gives one of the desired components for synthesis of chloroquine – 4,7-dichloroquinoline (37.1.1.1).
The second method of preparing of 4,7-dichloroquinoline (37.1.1.1) consists of reacting 3-chloroaniline with the diethyl ester of oxaloacetic acid in the presence of acetic acid to give the corresponding enamine (37.1.1.8), which when heated to 250 ° C undergoes heterocyclization to the ethyl ester of 7-chloro-4-hydrozyquinolin-2-carboxylic acid (37.1.1.9) accompanied with a small amount of 5-chloro-4-hydroxyquinolin-2-carboxylic acid (37.1.1.10), which is separated from the main product by crystallization from acetic acid. Alkaline hydrolysis of the ethyl ester of the 7-chloro-4-hydroxyquinolin-2-carboxylic acid (37.1.1.9) and subsequent high-temperature decarboxylation of the resulting acid (37.1.1.11) gives 7-chloro-4-hydroxyquinolin (37.1.1.7). Reacting this with phosphorus oxychloride using the scheme described above gives 4,7-dichloroquineoline (37.1.1.1).

Finally, the third of the suggested variants for making 4,7-dichloroquinoline (37.1.1.1) consists of reacting 3-chloroaniline with the ethyl ester of formylacetic acid to make the enamine (37.1.1.12), which on heating directly cyclizes to 7-chloro-4-hydroxyquinoline (37.1.1.7). Reacting this with phophorus oxychloride according to the scheme already described gives 4,7-dichloroquinoline (37.1.1.1).

The second component necessary for synthesizing of the chloroquine is 4-diethylamino- 1-methylbutylamine (37.1.1.2), is also made in various ways. Alkylating acetoacetic ester with 2-diethylaminoethylchloride gives 2-diethylaminoethylacetoacetic acid ester (37.1.1.13), which upon acidic hydrolysis (using hydrochloric acid) and simultaneous decarboxylation makes 1-diethylamino-4-pentanone (37.1.1.14). Reductive amination of this compound with hydrogen and ammonia using Raney nickel as a catalyst gives 4-diethylamino-1-methylbutylamine (37.1.1.2).

50-63-5 Synthesis

50-63-5
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54-05-7
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Yield:54-05-7 94%

Reaction Conditions:

with sodium hydroxide in water;ethyl acetate at 0; for 1 h;

Steps:

1
At 0°C, 13.0 g of chloroquine phosphate was dissolved in 75 ml of water, then 50 ml of 12% NaOH aqueous solution was added, and after stirring for half an hour, 25 ml of ethyl acetate was added, and stirring was continued for half an hour. The reaction solution was naturally warmed to room temperature, extracted three times with 100 ml of ethyl acetate, and the organic phases were combined, washed with 150 ml of saturated brine and water in turn, dried with anhydrous sodium sulfate, and filtered to remove sodium sulfate. The organic solvent was removed with a rotary evaporator to obtain 7.6 g of free chloroquine in the shape of a pale yellow viscous liquid with a yield of 94%.

References:

South University of Science and Technology of China;Li Guanguan;Shi Yongjie;Li Yingjun;Zhang Xumu CN111620815, 2020, A Location in patent:Paragraph 0163-0168

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86-98-6 Synthesis