The Synthetic Routes of 4-HYDROXY-2-METHYLQUINOLINE-6-CARBOXYLIC ACID ETHYL ESTER

4-Hydroxy-2-methylquinoline-6-carboxylic acid ethyl ester is a highly sought-after compound in the pharmaceutical and chemical industries due to its potential therapeutic properties.
It is an intermediate in the synthesis of certain drugs and has shown to have anti-inflammatory, antioxidant, and anticancer properties.

One of the most common synthetic routes to obtain 4-hydroxy-2-methylquinoline-6-carboxylic acid ethyl ester involves the use of a three-step synthesis involving the condensation of 4-hydroxy-2-methylquinoline-6-carboxylic acid with ethyl 2-chloroacetate, followed by esterification and hydrolysis.

Step 1: Condensation of 4-hydroxy-2-methylquinoline-6-carboxylic acid with ethyl 2-chloroacetate

The first step in the synthesis of 4-hydroxy-2-methylquinoline-6-carboxylic acid ethyl ester involves the condensation of 4-hydroxy-2-methylquinoline-6-carboxylic acid with ethyl 2-chloroacetate.
This reaction is typically carried out in the presence of a solvent such as dichloromethane or chloroform, and a base such as pyridine or triethylamine.
The reaction is exothermic and requires careful monitoring to avoid overheating.
Once the reaction is complete, the mixture is allowed to cool to room temperature, and the organic layer is separated and dried over anhydrous sodium sulfate.

Step 2: Esterification of 4-hydroxy-2-methylquinoline-6-carboxylic acid ethyl ester

The second step in the synthesis of 4-hydroxy-2-methylquinoline-6-carboxylic acid ethyl ester involves the esterification of the 4-hydroxy-2-methylquinoline-6-carboxylic acid ethyl ester with ethanol in the presence of a catalyst such as sodium hydroxide or potassium hydroxide.
This reaction is typically carried out in a solvent such as water or dioxane, and the mixture is stirred for several hours at room temperature.
Once the reaction is complete, the mixture is neutralized with hydrochloric acid and extracted with a solvent such as dichloromethane or chloroform.
The organic layer is then dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the desired product.

Step 3: Hydrolysis of 4-hydroxy-2-methylquinoline-6-carboxylic acid ethyl ester

The final step in the synthesis of 4-hydroxy-2-methylquinoline-6-carboxylic acid ethyl ester involves the hydrolysis of the ester group to obtain the carboxylic acid.
This reaction is typically carried out in the presence of a solvent such as water or methanol, and a base such as sodium hydroxide or potassium hydroxide.
The mixture is stirred for several hours at room temperature, and the reaction is monitored by TLC or HPLC.
Once the reaction is complete, the mixture is neutralized with hydrochloric acid or sodium bicarbonate, and the organic layer is extracted with a solvent such as ethyl acetate or dichloromethane.
The organic layer is then dried over anhydrous sodium sulfate and concentrated under vacuum to obtain the desired product.

Overall, the synthesis of 4-hydro