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28th May 2011 @ 09:07
Hydrolysis of racemic praziquantel (PZQ) was undertaken in order to isolate racemic praziquanamine (PZQ amine). Racemic PZQ was subjected to 1 M HCl in ethanol under a 23 hour reflux.

PZQ Hydrolysis BMSPDYL 1-1

To a mixture of 60mL 1 M HCl and 15 mL ethanol was added PZQ (2.0063 g, 6.42 mmol; M.W. = 312.41 g/mol). The mixture was then stirred and heated to reflux for 22 hours.

The reaction was allowed to cool to room temperature, upon which it was washed twice with 6 mL of EtOAc. Upon cooling in an ice bath, the solution was treated with 10M NaOH until the pH of the solution was determined to be 12 (using pH paper). The solution was then extracted three times with 10 mL of methylene dichloride. The combined organic layers were subsequently washed with 7 mL of brine (pH 12). The organic layers were then dried with anhydrous sodium sulfate, upon which the solvent was evaporated off using a rotary evaporator.

Yield: 1.0232 g; 79%
Appearance: clear, yellowish oil. The oil solidified after approximately 45 minutes to yield a yellowish opaque solid.
Melting Point: 118 - 119°C

IR (KBr pellet): 3315.2 cm-1 (N–H stretch), ~3000 cm-1 (sp2 C–H stretch), 2897.9 cm-1 (sp3 C–H stretch), 1635.1 cm-1 (C=O amide stretch), ~1600 cm-1 (C=C aromatic stretch), 1440.8 cm-1 (C=C aromatic stretch), 1297.0 cm-1 (C–N stretch)

(1) Woelfe, M. et al. "The Resolution of Praziquantel". 2011.
Attached Files
PZQ Hydrolysis BMSPDYL 1-1