[6152-25-6] · C10H13N3O2 · (S)-(-)-5-(a-Phenylethyl)semioxamazide · (MW 207.26)
Physical Data: [a]D -103° (c 1.0, CHCl3).
Solubility: sol polar aprotic solvents; limited sol hexane, toluene, etc.
Preparative Method: conveniently prepared by sequential addition of (S)-(-)-a-phenylethylamine and Hydrazine to Diethyl Oxalate (eq 1).1
This reagent is commonly used for the optical resolution of various compounds. Racemic spiro[4.4]nonane-1,6-dione was the first compound to be resolved (55% overall yield).2 The corresponding semioxamazone was obtained in optically active pure form in two or three recrystallizations and hydrolyzed to (-)-(S)-spiro[4.4]nonane-1,6-dione in a refluxing methanol-water mixture in the presence of Iodine (eq 2).
In the field of arene tricarbonyl chromium complexes, racemic aldehydes can be resolved quantitatively by chromatographic separation of the corresponding semioxamazones. The first optical resolution was carried out on the semioxamazone made from the chromium tricarbonyl complex of o-anisaldehyde.3,4 The separation of the diastereomers was done by silica gel chromatography (eq 3). Chromium tricarbonyl complexes of m-anisaldehyde,4 of the trifluoromethyl analog of o-anisaldehyde,5 and of o-trimethylsilylbenzaldehyde6 have also been resolved by the same procedure.
The iron tricarbonyl complex of 2-formylbutadiene has been resolved by chromatographic separation of its chiral semioxamazones (eq 4).7
2,3-Dihydro-2-phenyl-4(1H)-quinolone has also been resolved by fractional crystallization of the corresponding chiral semioxamazones (eq 5).8
Guy Solladié & Françoise Colobert
University Louis Pasteur, Strasbourg, France