The Production Process of PYRAZOLO[1,5-A]PYRIMIDINE-3-CARBOXYLIC ACID ETHYL ESTER

The production process of Pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester, also known as Compound 1, is a complex and multi-step process that involves various chemical reactions and purification steps.
The final product, Pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester, is a key intermediate for the synthesis of several important pharmaceuticals and agricultural chemicals.

The production process of Pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester can be divided into several stages, including:

1. Synthesis of N-ferrocene carboxamide
   The first step in the production of Pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester is the synthesis of N-ferrocene carboxamide, which is synthesized by reacting ferrocene with ammonia in the presence of a strong acid catalyst, such as sulfuric acid.
   
2. Condensation reaction with ethyl acrylate
   Next, N-ferrocene carboxamide is reacted with ethyl acrylate in the presence of a condensation catalyst, such as a base, to form Pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester.
   
3. Purification of the product
   The product from the condensation reaction is then purified by various methods, including distillation, crystallization, and chromatography, to remove any impurities and to obtain a pure sample of Pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester.
   
4. Hydrolysis of the ester
   Finally, the Pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester is hydrolyzed by treatment with a strong acid, such as hydrochloric acid, to form the free acid.
   

In summary, the production process of Pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester involves the synthesis of N-ferrocene carboxamide, followed by a condensation reaction with ethyl acrylate, purification of the product, and finally hydrolysis of the ester to form the free acid.
This process requires a combination of chemical reactions and purification steps to obtain a pure sample of the final product, which is used as a key intermediate in the synthesis of various pharmaceuticals and agricultural chemicals.