The Instruction of 5-bromo-N-[[(2S)-1-ethylpyrrolidin-2-yl]methyl]-2,3-dimethoxybenzamide,hydrobromide

Instructions for the preparation of 5-bromo-N-[[(2S)-1-ethylpyrrolidin-2-yl]methyl]-2,3-dimethoxybenzamide, hydrobromide

1. Gather the necessary equipment and chemicals, including a 500 mL round-bottomed flask, a magnetic stirrer, a thermometer, a condenser, and a heating plate.
   
2. Place the flask on the heating plate and add 500 mL of toluene, followed by 100 g of 2,3-dimethoxybenzene.
   Stir the mixture until it is dissolved.
   
3. In a separate beaker, mix 50 g of 5-bromo-2-nitrobenzoxazole with 200 mL of toluene.
   Stir the mixture until it is dissolved.
   
4. Slowly add the 5-bromo-2-nitrobenzoxazole solution to the 2,3-dimethoxybenzene solution, stirring constantly.
   
5. Next, add 15 g of finely ground potassium carbonate to the mixture and stir for 30 minutes.
   
6. After 30 minutes, add 50 g of (2S)-1-ethylpyrrolidine to the mixture and stir for an additional 30 minutes.
   
7. After 30 minutes, filtrate the mixture through a bed of anhydrous sodium sulfate, and concentrate the filtrate to a volume of approximately 200 mL.
   
8. Add 200 mL of water to the concentrated mixture and stir until the mixture is clear.
   
9. Slowly add 200 mL of hydrobromic acid to the mixture, stirring constantly.
   
10. Allow the mixture to cool to room temperature, then stir in 200 mL of toluene and allow the mixture to settle.
    
11. Filter off the precipitated solid, wash it with 50 mL of toluene, and dry it under high vacuum.
    
12. The resulting solid can be recrystallized from 50 mL of toluene and 50 mL of hexane.
    
13. After recrystallization, obtain a pure sample of 5-bromo-N-[[(2S)-1-ethylpyrrolidin-2-yl]methyl]-2,3-dimethoxybenzamide, hydrobromide.
    

This is a general procedure for the preparation of 5-bromo-N-[[(2S)-1-ethylpyrrolidin-2-yl]methyl]-2,3-dimethoxybenzamide, hydrobromide.
Depending on the specific requirements of the final product, modifications to the procedure may be necessary.