The Synthetic Routes of Ethyl 8-bromo-5-methylimidazo[1,2-a]pyridine-2-carboxylate

Ethyl 8-bromo-5-methylimidazo[1,2-a]pyridine-2-carboxylate is a chemical compound that is widely used in various industrial applications.
This compound is synthesized through different synthetic routes depending on the specific requirements of the application.
This article will discuss two of the most common synthetic routes for the production of Ethyl 8-bromo-5-methylimidazo[1,2-a]pyridine-2-carboxylate.

Route 1: Starting with 8-bromo-5-methylimidazo[1,2-a]pyridine-2-carboxylic acid

The first synthetic route for Ethyl 8-bromo-5-methylimidazo[1,2-a]pyridine-2-carboxylate involves the use of 8-bromo-5-methylimidazo[1,2-a]pyridine-2-carboxylic acid as the starting material.
This acid is first synthesized through a series of chemical reactions, which involve the condensation of 2-chloro-5-methyl-6-nitropyridine with 2-aminomethyl-1,3-oxazolidine.
The resulting acid is then treated with ethyl iodide in the presence of a Lewis acid catalyst to form Ethyl 8-bromo-5-methylimidazo[1,2-a]pyridine-2-carboxylate.

Route 2: Starting with 2-chloro-5-methyl-6-nitropyridine

The second synthetic route for Ethyl 8-bromo-5-methylimidazo[1,2-a]pyridine-2-carboxylate involves the use of 2-chloro-5-methyl-6-nitropyridine as the starting material.
This compound is first synthesized by reacting 2-aminomethyl-1,3-oxazolidine with Cl2, followed by treatment with N-bromosuccinimide to form 2-bromo-5-methyl-6-nitropyridine.
This intermediate is then transformed into 2-chloro-5-methyl-6-nitropyridine by treatment with NaNO2 and HCl.
The 2-chloro-5-methyl-6-nitropyridine is then treated with ethyl iodide in the presence of a Lewis acid catalyst to form Ethyl 8-bromo-5-methylimidazo[1,2-a]pyridine-2-carboxylate.

Chemical Reactions Involved in the Synthesis of Ethyl 8-bromo-5-methylimidazo[1,2-a]pyridine-2-carboxylate

Both of the above-described synthetic routes involve the use of ethyl iodide and a Lewis acid catalyst to form Ethyl 8-bromo-5-methylimidazo[1,2-a]pyridine-2-carboxylate.
The reaction can be described as follows:

EtI + 2-chloro-5-methyl-6-nitropyridine → Et 8-bromo-5-methylimidazo[1,2-a]pyridine-2-carboxylate

In this reaction, the ethyl iodide molecule attacks the carbon atom of 2-chloro-5-methyl-6-nitropyridine, forming an intermediate carbocation.
The Lewis acid catalyst then abstracts a proton from the intermediate, leading to the formation of the