The Production Process of 4,5-Dichloro-2-m-tolylpyridazin-3(2H)-one

The production process of 4,5-dichloro-2-m-tolylpyridazin-3(2H)-one, also known as MAPK inhibitor, is a complex and multi-step process that involves several chemical reactions and purification steps.
The following is a detailed overview of the production process of this compound in the chemical industry.

Step 1: Diazotization Reaction
The production of 4,5-dichloro-2-m-tolylpyridazin-3(2H)-one starts with the diazotization reaction, which involves the conversion of aniline (2-m-tolylaniline) to a diazonium salt.
This reaction is carried out in the presence of a diazotizing agent such as nitrous acid or hydrazine, and a catalyst such as sulfuric acid or hydrochloric acid.
The reaction conditions involve heating the reaction mixture to a temperature of 80-100°C for 1-2 hours.

Step 2: Chlorination Reaction
After the diazotization reaction, the next step is the chlorination reaction, which involves the conversion of the diazonium salt to the corresponding chloride.
This reaction is carried out in the presence of a chlorinating agent such as chlorine gas or hydrochloric acid, and a catalyst such as ferric chloride.
The reaction conditions involve heating the reaction mixture to a temperature of 60-70°C for 1-2 hours.

Step 3: Decarboxylation Reaction
The next step in the production process is the decarboxylation reaction, which involves the removal of the carboxyl group from the chloride salt.
This reaction is carried out in the presence of a decarboxylating agent such as sodium hydroxide or potassium hydroxide, and the reaction mixture is heated to a temperature of 80-90°C for 1-2 hours.

Step 4: Pyridazine Ring Synthesis
The next step is the synthesis of the pyridazine ring, which is carried out by heating the decarboxylated salt with a nitrogen nucleophile such as ammonia or a primary amine.
The reaction mixture is heated to a temperature of 80-90°C for 1-2 hours, after which the reaction is completed by cooling the mixture to room temperature.

Step 5: Formation of the Final Product
The final step in the production process is the formation of the final product, 4,5-dichloro-2-m-tolylpyridazin-3(2H)-one.
This is carried out by treating the pyridazine ring with a chlorinating agent such as chlorine gas or hydrochloric acid, in the presence of a catalyst such as ferric chloride.
The reaction mixture is heated to a temperature of 60-70°C for 1-2 hours, after which the reaction is completed by cooling the mixture to room temperature.

Purification of the Final Product
After the production of the final product, it is necessary to purify it to remove any impurities that may have been introduced during the production process.
This is typically done using a combination of crystallization, distillation, and chromatography techniques.

Overall, the production process of 4,5-dichloro-2-m-tolylpyridazin-3(2H)-one is a complex and multi-step process that involves several chemical reactions and purification steps.
The success of the process depends on the selection of appropriate reaction conditions, the use of suitable reagents and catalysts, and the ability to efficiently purify the final product.
The production of this compound requires advanced equipment and skilled operators, and is carried out in dedicated chemical plants.