Formation of an oxazolidonone ring using carbonyldiimidazole; 3,4-Dimethyl-5-phenyloxazolidin-2-one
SyntheticPage 476
DOI:
10.1039/SP476
Submitted Dec 21, 2010, published Feb 10, 2012
John Davidson (
jsdcrosslaw@tiscali.co.uk)
A contribution from
Crosslaw
Chemicals Used
ephedrine hydrate
carbonyldiimidazole
tetrahydrofuran
water
Procedure
A mixture of ephedrine hydrate (5.2 g, 0.03 mole) and carbonyldiimidazole (16 g) in THF (100 ml) was heated under reflux for 7h. The THF was distilled off in a current of steam, ice and water added, the mixture stirred, and then the solid which separated was filtered off and dried in a vacuum desiccator to afford the colourless solid product (4.55 g, 79%) .
Author's Comments
Carbonyldiimidazole is a safer alternative to phosgene. The large excess is required to react with the water from the hydrate and still leave enough to form the oxazolidinone ring.
Data
Mp 91-92° (needles from heptane) [α]D –121.9° (3.65% in CHCl3)
Found: C 69.1%, H 7.05%, N 7.2% Calc. for C11H13NO2: C 69.1%, H 6.85%, N 7.3%
Lead Reference
Beil,27, III, IV4, 2762; US 2,399,118 (1942)
Other References
Cf. John S. Davidson, Monatshefte für Chemie, 115, 565-571 (1984)
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Keywords: alcohols, amines, carbamates, Carbonylation, heterocyclic compounds, nucleophilic, substitution
