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22nd January 2012 @ 10:46
MNR3.png

MNR3-3_table.PNG

Hazard and Risk Assessment:
As for MNR2-1

rac-PZQamine (2.65 g, 13.10 mmol) and dibenzoyl-L-tartaric acid.2IPA (MNR6-1)(6.27 g, 13.10 mmol) was dissolved in a mixture of isopropanol (60 mL) and water (10 mL) by taking to reflux. The solution was allowed to cool to room temperature and stand overnight. The solid was then filtered and rinsed with IPA/water (5:1).

Crude salt (4.634 g) not dried under vacuum

MNR3-salt.png

The salt (4.634 g) was dissolved in a mixture of i-PrOH (50 mL) and water (25 mL) by heating (heat gun). It was then allowed to cool to room temperature and stand overnight. The solid was then filtered and rinsed with IPA/water (5:1).

The salt was then mixed with water (20 mL) and taken to pH 11 with the addition of NaOH solution (2M) and extracted with DCM (25 ml x 4) and the aqueous layer was pH adjusted to pH 2 using 2M HCl. The organic fractions were combined, washed with brine (30 mL) and dried over magnesium sulphate, filtered and concentrated under reduced pressure to give a white solid (0.779 g, 3.85 mmol, 59 %).

The combined washings from the two crystalisations were concentrated and mixed with water (20 mL) and taken to pH 11 with the addition of NaOH solution (2M) and extracted with DCM (25 ml x 4) and the aqueous layer was pH adjusted to pH 2 using 2M HCl. The organic fractions were combined, washed with brine (30 mL) and dried over magnesium sulphate, filtered and concentrated under reduced pressure to give a yellow solid (1.35 g, 6.67 mmol)

Total PZQ-amine recovered (2.129 g, 10.52 mmol, 80 %)

The aqueous layers were combined in an attempt to recover the resolving agent. Nothing precipitated out over night so the volume was reduced under vacuum.
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