The Synthetic Routes of 1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene

1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene, also known as phenanthrene, is an organic compound with the molecular formula C18H12N2.
It is a derivative of benzene, with two phenyl groups attached to the central carbon atom.
Phenanthrene has a long history in the chemical industry and has been studied extensively due to its unique properties and potential applications.

The synthesis of 1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene has been a subject of much research in the chemical industry.
There are several synthetic routes to this compound, which can be broadly classified into two categories: direct synthesis and indirect synthesis.

Direct Synthesis of 1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene:

The direct synthesis of 1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene involves the coupling of two phenyl-pyridine units to the benzene ring.
The most common method of direct synthesis involves the electrophilic substitution of the pyridine nucleus in the presence of a Lewis acid catalyst.
One of the most widely used methods is the Tishchenko reaction, which involves the use of a palladium catalyst.

The Tishchenko reaction involves the treatment of a halogenated benzene derivative with a solution of a pyridine derivative in the presence of palladium on barium sulfate.
The reaction proceeds through a free-radical mechanism, with the formation of a palladium-pyridine complex that undergoes a series of rearrangements to form the desired product.

Another commonly used method for the direct synthesis of 1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene is the Heck reaction.
This reaction involves the combination of a phenylboronic acid derivative with a pyridine derivative in the presence of a palladium catalyst.
The reaction proceeds through a metallocene mechanism, with the formation of a palladium-boron complex that undergoes a series of rearrangements to form the desired product.

Indirect Synthesis of 1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene:

The indirect synthesis of 1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene involves the synthesis of the pyridine derivative followed by its coupling with the benzene ring.
One of the most commonly used methods for the synthesis of the pyridine derivative is the nitration of 3-pyridinecarboxaldehyde, followed by reduction of the resulting nitro compound.

The coupling of the pyridine derivative with the benzene ring can be achieved through a variety of methods, including the use of a Friedel-Crafts catalyst, the Grignard reaction, or the Suzuki reaction.
The Friedel-Crafts catalyst is typically a noble metal, such as ruthenium or iridium, that activates the carbon atom of the benzene ring towards electrophilic substitution reactions.

The Grignard reaction involves the treatment of a metal halide with a primary or secondary alkyl halide in the presence of a Lewis acid catalyst, such as zinc chloride or aluminum chloride.
The resulting Grignard reagent can then be treated with water to form a carboxylic acid derivative, which can be converted to the desired pyridine derivative through a series of chemical transformations.

The Suzuki reaction involves the use of a boronic acid derivative and a palladium catalyst to form a carbon-boron bond.
The boronic acid derivative can be synth