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21st June 2012 @ 01:27
Resolution of MNR26-5 with (+)-dibenzoyl-D-tartaric acid (MNR5-1)


Hazard and Risk Assessment:
As for MNR2-1

MNR26-5 (EtOAc wash fraction) (1.10 g, 4.19 mmol) and MNR5-1 (1.62 g, 4.19 mmol) was dissolved in IPA (10 mL) and water (2 mL) with heating. All the reagents went into solution and the mixture was left to stand. After 3 hours everything remained in solution so the flask was transferred to the freezer. After 1 hour the solution had frozen so the flask was allowed to reach room temperature again by which time it turned back into a solution. The flask was then stored in the fridge over the weekend by which time white lumpy crystals had formed. These were filtered and washed with IPA:Water (8:1) then hexane and dried to give a white solid 0.908 g, 1.46 mmol, 70%
Test workup
salt (0.036 g, 0.058 mmol) was treated with sodium carbonate solution (5 mL) and extracted with EtOAc (20 ml x 5). The organic fractions were dried, filtered and concentrated to give a clear oil 0.014 g, 0.053 mmol, 91 %)
HPLC showed 75% ee
The remaining salt was dissolved in IPA (18 mL) and water (3 mL) and stored in the fridge overnight. The white solid was filtered and washed with IPA and hexane to recover 100% of what was used therefore no further improvement on the ee. The solid was redissolved in IPA (30 mL) and water (3ml) with heating and allowed to stand.

Conical flask found in the freezer (15/10/12) wih nice white crystals in solution. Filtered and washed with Et2O and dried under vacuum.

Vial tare - 16.131 g