反应详情

A slurry of (±)-N-[[3-(3-fluoro-4-iodophenyl)-2-oxo-5-oxazolidinyl]methyl]acetamide (PREPARATION 18, 0.063 g, 0.165 mmol) and trimethyl(4-pyridyl)tin (0.060 g, 0.248 mmol) in 1,4-dioxane (5 ml) is degassed by repeated evacuation and filling with nitrogen. Bis(triphenylphosphine)palladium (II) chloride (0.012 g, 0.0165 mmol) is added, the reaction again degassed, and then the mixture is brought to reflux under nitrogen. After 4 hr TLC (silica gel, 10% methanol/chloroform) reveals some of the iodide still remains. The mixture is refluxed a further 20 hr, cooled to 20-25°, and concentrated under reduced pressure. The residue is chromatographed over silica gel, eluting with a little chloroform and then methanol/chloroform (1%, 2%, and then 5%). The appropriate fractions are pooled and concentrated to give the enantiomerically enriched title compound, mp 190.5-191.0°; [α]25D -16.40 (c 0.5, CHCl3). The following characteristics are noted for a racemic sample, mp 179-180°; IR (internal reflectance) 3279, 3063, 1756, 1752, 1657, 1626, 1600, 1542, 1522, 1485, 1412, 1407, 1377, 1222, 1198 cm-1 ; NMR (CDCl3, 300 MHz) 8.67, 7.59, 7.50, 7.47, 7.33, 6.15, 4.84, 4.11, 3.85, 3.78-3.62, 2.04 δ; MS (m/z) 329 (39.8, M+), 285, 257, 201, 172, 73 and 42. ##STR3##

1. customthe reaction
2. customagain degassed
3. temperatureto reflux under nitrogen
4. temperatureThe mixture is refluxed a further 20 hr
5. temperaturecooled to 20-25°
6. concentrationconcentrated under reduced pressure
7. customThe residue is chromatographed over silica gel
8. washeluting with a little chloroform
9. concentrationconcentrated