The Production Process of Dodecahydro-[5,5'-biisobenzofuran]-1,1',3,3'-tetraone

Dodecahydro-[5,5'-biisobenzofuran]-1,1',3,3'-tetraone, also known as “biscarin” or “3,3′-dichloro-2,2′-oxo-biisoindoline-5,5′-dione”, is a synthetic chemical that has a wide range of potential industrial and commercial applications.
Its complex molecular structure, which features a benzofuran central ring flanked by two bromine and two chlorine atoms, makes it an attractive building block for the synthesis of novel materials and compounds.
In this article, we will explore the production process of dodecahydro-[5,5'-biisobenzofuran]-1,1',3,3'-tetraone, from raw materials to final product.

Step 1: Preparation of the Starting Materials

The production of dodecahydro-[5,5'-biisobenzofuran]-1,1',3,3'-tetraone begins with the preparation of the starting materials.
The key intermediate in the synthesis of biscarin is 2,2′-dibromo-3,3′-dichloro-indoline, which is synthesized by a sequence of reactions from the starting material 2,2′-dibromo-indoline.

The synthesis of 2,2′-dibromo-indoline typically involves the reaction of 2,2′-dibromo-acetophenone with hydroiodic acid in the presence of a Lewis acid catalyst, such as aluminum chloride.
The resulting product is then treated with a base, such as sodium hydroxide, to convert the acetate group to a phenolic hydroxyl group.
The bromine atoms are then introduced by reaction with a brominating agent, such as N-bromosuccinimide, in the presence of a solvent, such as carbon tetrachloride.

Step 2: Condensation Reactions

Once the starting materials have been prepared, the next step in the production of biscarin is the condensation reaction.
This step involves the formation of the 1,1′,3,3′-tetraoxa-bicyclo[3.
3.
1]nonane ring system, which is a key feature of the molecule's structure.

There are several different methods that can be used to perform the condensation reaction, depending on the specific starting materials and desired product.
One common method involves the use of a strong acid catalyst, such as phosphoric acid or sulfuric acid, to catalyze the reaction between the 2,2′-dibromo-3,3′-dichloro-indoline starting material and a molecule such as glyoxal or m-phenylenediamine.
The resulting product is then treated with a base, such as sodium hydroxide, to remove the acid catalyst and neutralize the reaction mixture.

Step 3: Coupling Reactions

The next step in the production of biscarin is the coupling reaction, which involves the formation of the six-membered benzofuran ring system.
This step can be performed using a variety of different reaction conditions and reagents, depending on the specific starting materials and desired product.

One common method for performing the coupling reaction involves the use of a reagent such as potassium permanganate, which is added to the reaction mixture containing the intermediate condensation product.
The potassium permanganate oxidizes the intermediate product, leading to the formation of the six-membered benzofuran ring system.

Step 4: Hydrolysis and Purification

After the coupling reaction has been completed, the resulting product is typically hydrolyzed to remove any remaining acidic or basic functional groups.
This step is typically performed using a strong base, such as sodium hydroxide, which reacts with any remaining acidic groups to form a water