Racemic Resolution of Praziquantel and Praziquanamine

 

Preparation of MNR34-1 - Step 1 in the alternative route to MNR26





Hazard and Risk Assessment:
MNR34

Procedure

3,4-dimethoxyphenethylamine (8 mL, 48.17 mmol) and NaHCO3 (4.05 g, 48.17 mmol) were dissolved in DCM (60 mL) at room temperature under argon. The mixture was cooled to 0 °C and chloroacetyl chloride (4.05 mL, 48.17 mmol) was added dropwise. The reaction mixture was stirred at 0 °C for 2 hours. Water (50 mL) was slowly added and the aqueous phase was extracted with DCM (100 mL). The organic layers were combined, washed with an aqueous solution of HCl (2M , 50 mL), dried with MgSO4, filtered, concentrated,and dried under vacuum. The crude off white solid was obtained and was recrystalised with EtOH/Hexane. The white crystals were washed with hexane to give fine white crystals.

1st crop 6.352 g, 24.65 mmol, 51 % as fine white crystals

2nd crop 1.017 g, 3.95 mmol, 8 % as fine white crystals

1H NMR