The Synthetic Routes of 4,4'-Bis(N-carbazolyl)-1,1'-biphenyl

4,4'-Bis(N-carbazolyl)-1,1'-biphenyl, also known as BCB (Bis(2-(4',4'-diaminobiphenylamino)phenyl) carbonate), is a widely used material in the electronic industry due to its excellent electrical and thermal properties.
It is commonly used as an organic semiconductor material in thin film transistors, organic light-emitting diodes, and solar cells.
The compound is synthesized through several synthetic routes, some of which are described in this article.

One of the most commonly used synthetic routes for BCB involves the reaction of 2-(4',4'-diaminobiphenylamino)phenyl)propanamide with 4,4'-dichlorobiphenyl in the presence of a catalyst such as pyridine.
The reaction produces a mixture of two isomers, trans-BCB and cis-BCB, which are separated via column chromatography.
This method provides good yield, but it is highly sensitive to the reaction conditions and requires strict control to avoid unwanted side reactions.

Another synthetic route involves the reaction of 1,1'-bis(4,4'-diaminobiphenylamino)biphenyl-2,2'-dicarboxylic acid with 4,4'-dichlorobiphenyl in the presence of a solvent such as DMF.
The reaction produces a mixture of trans- and cis-isomers, which can be separated via recrystallization.
This method is less sensitive to the reaction conditions than the previous method and provides good yield.

A third synthetic route involves the reaction of 4,4'-diaminobiphenyl with 2-(4',4'-dichlorobiphenylamino)phenyl)propanamide in the presence of a catalyst such as DEAD.
The reaction produces a mixture of trans- and cis-isomers, which can be separated via column chromatography.
This method provides good yield, but it is more complex and requires more steps than the previous methods.

All the above synthetic routes have their own advantages and disadvantages, but the most commonly used route for industrial production of BCB is the first method because it provides high yield and good purity of the product.
However, a new synthetic route for BCB has been recently discovered which has been reported to be more efficient than the traditional methods.

The new synthetic route for BCB involves the reaction of 4-Nitrobiphenyl with 4-(N-carbazolyl)aniline in the presence of a solvent such as DMF.
The reaction produces a mixture of trans- and cis-isomers, which can be separated via recrystallization.
This method provides good yield, it is easier and less sensitive to the reaction conditions than the traditional methods.

In conclusion, BCB is an important organic semiconductor material with excellent electrical and thermal properties.
Several synthetic routes have been reported for the synthesis of BCB, and the most commonly used route involves the reaction of 2-(4',4'-diaminobiphenylamino)phenyl)propanamide with 4,4'-dichlorobiphenyl in the presence of a catalyst such as pyridine.
However, the new synthetic route discovered recently which involves the reaction of 4-Nitrobiphenyl with 4-(N-carbazolyl)aniline in the presence of a solvent such as DMF has been reported to be more efficient and easier to perform.
This new route is expected to have a significant impact on the industrial production of BCB.