The Synthetic Routes of Isoxazolo[4,5-b]pyridin-3-amine (9CI)

Isoxazolo[4,5-b]pyridin-3-amine, also known as 9CI, is an important intermediate in the synthesis of various pharmaceuticals, agrochemicals, and dyes.
The demand for this compound has been increasing in recent years due to its wide range of applications in various industries.
Synthesizing 9CI requires the use of various techniques and methods, and there are different synthetic routes that can be used to produce this compound.

One of the most common methods for synthesizing 9CI is through the nitration of pyridine-3-amine, which involves the addition of nitrating acid to the amine to form the nitro compound.
This compound is then reduced using a reducing agent, such as hydrazine, to form the isoxazolo[4,5-b]pyridin-3-amine.

Another route for synthesizing 9CI is through the oxidation of N-methyl-isoindoline-1,9-dione.
This involves the formation of N-methyl-isoindoline-1,9-dione through the condensation of methyl-isoindoline-1,9-dione with another compound, followed by oxidation of the N-methyl group using an oxidizing agent, such as potassium permanganate.
The resulting compound is then reduced to form 9CI.

Yet another route for synthesizing 9CI is through the condensation of isatin with an aromatic aldehyde, such as benzaldehyde.
This involves the formation of an isatin-aldehyde adduct, which is then cyclized under acidic conditions to form the isoxazolo[4,5-b]pyridin-3-amine.

The choice of synthetic route for 9CI depends on various factors, such as the availability and cost of starting materials, the desired yield and purity of the final product, and the scalability of the process.
Some routes may be more suitable for large-scale synthesis, while others may be more appropriate for laboratory-scale synthesis.

One major advantage of synthesizing 9CI is that it can be used as an intermediate in the synthesis of various pharmaceuticals, agrochemicals, and dyes.
For example, it can be used in the synthesis of anti-inflammatory drugs, such as celecoxib and lumiracoxib, and antihistamines, such as cetirizine and levocetirizine.
It is also used as an intermediate in the synthesis of herbicides, such as imidazolinone herbicides, and dyes, such as malachite green.

In conclusion, the synthetic routes of isoxazolo[4,5-b]pyridin-3-amine (9CI) are diverse and include nitration of pyridine-3-amine, oxidation of N-methyl-isoindoline-1,9-dione, and condensation of isatin with an aromatic aldehyde.
The choice of synthetic route depends on various factors, such as the availability and cost of starting materials, the desired yield and purity of the final product, and the scalability of the process.
The compound is widely used as an intermediate in the synthesis of various pharmaceuticals, agrochemicals, and dyes, and its demand is expected to continue increasing in the future.