Piroctone olamine can be synthesized through a variety of routes, but the most common method involves the reaction of 2-amino-4-nitrophenol with chloroacetamide to produce 2-(2,4-dinitroanilino)-2-imidazoline, which is then reacted with 2-aminoethanol to form piroctone olamine.

Another synthetic route involves the reaction of 2-amino-4-nitrophenol with chloroacetic acid to produce 2-(2,4-dinitroanilino)-2-hydroxyacetic acid, which is then converted to piroctone olamine through a series of steps involving phosphorus oxychloride, ammonia, and potassium hydroxide.

There are also other routes as follows:

1. One method involves the reaction of 2-amino-4-nitrophenol with chloroacetyl chloride to produce 2-(2,4-dinitroanilino)-N-(chloroacetyl)acetamide, which is then reacted with 2-aminoethanol to form piroctone olamine.

2. Another method involves the reaction of 2-amino-4-nitrophenol with chloroacetic acid to produce 2-(2,4-dinitroanilino)-2-hydroxyacetic acid, which is then reduced with sodium borohydride to form 2-(2,4-dinitroanilino)-2-hydroxyethylamine. This compound is then reacted with chloroacetyl chloride to form 2-(2,4-dinitroanilino)-N-(chloroacetyl)-2-hydroxyethylamine, which is finally reacted with ammonia to form piroctone olamine.

3. A third method involves the reaction of 2-amino-4-nitrophenol with chloroacetic acid to produce 2-(2,4-dinitroanilino)-2-hydroxyacetic acid, which is then reacted with thionyl chloride to form 2-(2,4-dinitroanilino)-2-chloroacetyl chloride. This compound is then reacted with 2-aminoethanol to form piroctone olamine.

These are just a few examples of the different synthetic routes that have been reported in the literature for the synthesis of piroctone olamine.

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