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20th January 2011 @ 05:38
Racemization experiments of enantioenrichend S-(+)-PZQamine, obtained from Multigram-scale racemic resolution of praziquanamine, with (-)-Dibenzoyl-L-tartaric acid (MW49-13), with Pd supported on barium sulfate

Scheme MW50-5.png

See also:
Racemization of S-(+)-PZQamine with Pd/C (MW50-1 to MW50-3)
Racemization of S-(+)-PZQamine with Pd/C (MW50-4)
Racemization of S-(+)-PZQamine with Raney Nickel (MW50-6, MW50-7)
Thiyl radical-mediated racemization of S-(+)-PZQamine (MW50-8)

Hazard and Risk Assessment:
HRAF MW50.pdf

Start time: 5:00 PM 20/01/2011
End time: 5:00 PM 24/01/2011

To a solution of S-(+)-PZQamine (20 mg, 98.9 µmol, MW: 202.3 g/mol) in toluene (5 mL) was added Pd/BaSO4 (5.27 mg, 4.95 µmol, 0.05 eq.; 10% Pd on BaSO4, M.W. (Pd) 106.4 g/mol) and heated to 70°C for 4 days.

[α]D20 = -24.8° (c=1, DCM) -> racemization

Data: 1H NMR MW50-5.pdf: no more PZQamine - sompletely decomposed

[1] "Efficient dynamic kinetic resolution of secondary amines with Pd on alkaline earth salts and a lipase", Andrei Parvulescu, Dirk De Vos and P. Jacobs, Chem. Commun. 2005, 5307-5309. (DOI: 10.1039/B509747A)
Attached Files
Scheme MW50-5.png
1H NMR MW50-5.pdf