The Production Process of 4-Isoquinolinecarboxylic acid, ethyl ester

4-Isoquinolinecarboxylic acid, ethyl ester is an important intermediate chemical used in the production of various pharmaceuticals and agrochemicals.
The production process of 4-Isoquinolinecarboxylic acid, ethyl ester involves several steps, each of which is critical to the final product.
In this article, we will discuss the production process of 4-Isoquinolinecarboxylic acid, ethyl ester in detail.

Step 1: Synthesis of 4-Chloro-3-nitroanthranilic acid
The synthesis of 4-Chloro-3-nitroanthranilic acid is the first step in the production process of 4-Isoquinolinecarboxylic acid, ethyl ester.
4-Chloro-3-nitroanthranilic acid is synthesized by chlorination of 3-nitroanthranilic acid using chlorine gas.
The reaction is exothermic, and the reaction mixture is cooled to prevent excessive heating.

Step 2: Reduction of 4-Chloro-3-nitroanthranilic acid to 3-Amino-4-chloroanthranilic acid
The 4-Chloro-3-nitroanthranilic acid is reduced to 3-Amino-4-chloroanthranilic acid using hydrogen in the presence of a reducing agent such as platinum on barium oxide or palladium on charcoal.
The reduction reaction is carried out at a moderate temperature and pressure to prevent the formation of unwanted side products.

Step 3: Nitration of 3-Amino-4-chloroanthranilic acid
In the next step, 3-Amino-4-chloroanthranilic acid is nitrated using nitric acid to produce 3-Nitro-4-chloroanthranilic acid.
This reaction is exothermic, and the reaction mixture is cooled to prevent excessive heating.

Step 4: Reduction of 3-Nitro-4-chloroanthranilic acid to 4-Chloro-3-nitroanthranilic acid
The 3-Nitro-4-chloroanthranilic acid is reduced to 4-Chloro-3-nitroanthranilic acid using hydrogen in the presence of a reducing agent such as platinum on barium oxide or palladium on charcoal.
This step is carried out at a moderate temperature and pressure to prevent the formation of unwanted side products.

Step 5: Coupling of 4-Chloro-3-nitroanthranilic acid with Phenyl Acetate
In the final step of the production process, 4-Chloro-3-nitroanthranilic acid is coupled with phenyl acetate in the presence of a coupling agent such as manganese dioxide, sulfuric acid, and sodium hydroxide.
The reaction is carried out at a moderate temperature and pressure, and the reaction mixture is stirred to ensure complete reaction.

Overall Production Process
The overall production process of 4-Isoquinolinecarboxylic acid, ethyl ester involves several steps, including the synthesis of 4-Chloro-3-nitroanthranilic acid, its reduction to 3-Amino-4-chloroanthranilic acid, nitration of 3-Amino-4-chloroanthranilic acid, reduction of 3-Nitro-4-chloroanthranilic acid to 4-Chloro-3-nitroanthranilic acid, and finally, the coupling of 4-Chloro-3-nitroanthranilic acid with phenyl ac