The Synthetic Routes of 4-CYANO-2-IODOPYRIDINE

4-Chloro-2-iodopyridine is a commonly used intermediate in the production of various pharmaceuticals, agrochemicals, and other chemical products.
There are several methods for its synthesis, including synthetic routes that involve the use of various reagents, catalysts, and reaction conditions.
In this article, we will discuss some of the most popular synthetic routes for 4-chloro-2-iodopyridine.

1. Hydrochloric acid route

The first synthetic route for 4-chloro-2-iodopyridine involves the use of hydrochloric acid.
To begin, nitrobenzene is treated with sodium hydroxide to form benzaldehyde, which is then reacted with hydrochloric acid and sodium nitrite in the presence of sodium hydroxide to form 4-chloro-2-iodopyridine.

Advantages:

• Simple and straightforward process
• Inexpensive reagents
• High yielding

Disadvantages:

• The reaction involves the use of hazardous reagents such as hydrochloric acid and sodium nitrite
• The reaction requires careful handling and disposal of the hazardous reagents

2. N-Bromosuccinimide route

The second synthetic route for 4-chloro-2-iodopyridine involves the use of N-bromosuccinimide (NBS).
To begin, 4-chloro-2-iodopyridine is treated with NBS in the presence of a polar solvent such as water or dimethylformamide to form the corresponding N-bromides.
These N-bromides are then hydrolyzed using a Base to form 4-chloro-2-iodopyridine.

Advantages:

• Simple and straightforward process
• High yielding
• Can be used to prepare other N-bromides

Disadvantages:

• The reaction requires the use of hazardous reagents such as NBS and Base
• The reaction can generate hazardous byproducts such as hydrogen bromide

3. Phosphorus Trichloride route

The third synthetic route for 4-chloro-2-iodopyridine involves the use of phosphorus trichloride.
To begin, 2-iodopyridine is treated with phosphorus trichloride and a solvent such as ether or hexane to form 4-chloro-2-iodopyridine.

Advantages:

• Simple and straightforward process
• High yielding
• Can be used to prepare other halides

Disadvantages:

• The reaction involves the use of a hazardous reagent such as phosphorus trichloride
• The reaction can generate hazardous byproducts such as phosphorus oxychloride

4. other routes like from 4-bromo-2-iodopyridine or 2-iodopyridine-N-oxide route also available which are less common

In conclusion, the synthetic routes for 4-chloro-2-iodopyridine vary, and each route has its own advantages and disadvantages.
The selection of a particular route depends on various factors, such as the availability of reagents, the yield of the desired product, and the safety and environmental considerations.
It is important to carefully evaluate the risks and benefits of each route to ensure the safe and efficient synthesis of 4-chloro-2-iodopyridine.