反应详情

A mixture of benzoin (6.00 g, 28 mmol), azelaic acid monomethyl ester (7.17 g of 92% pure material, 32 mmol), 1,3-dicyclohexylcarbodiimide (7.00 g, 34 mmol), 4-dimethylaminopyridine (catalytic amount) and dichloromethane (120 mL) was stirred at room temperature. After 16 hours, the mixture was filtered and the solvent evaporated. Ammonium acetate (10.90 g, 141 mmol) and acetic acid (150 mL) were added to the residue and the mixture heated at reflux for 65 minutes before being cooled and diluted with water. The mixture was extracted with diethyl ether, the combined extracts dried over sodium sulfate and concentrated in vacuo. The residual oil was chromatographed on a column of silica gel using a mixture of hexanes and diethyl ether (7:3) as eluent to give methyl 4,5-diphenyl-2-oxazoleoctanoate (8.24 g, 77%) as an oil.

1. filtrationthe mixture was filtered
2. customthe solvent evaporated
3. temperaturethe mixture heated
4. temperatureat reflux for 65 minutes
5. temperaturebefore being cooled
6. extractionThe mixture was extracted with diethyl ether
7. dry with materialthe combined extracts dried over sodium sulfate
8. concentrationconcentrated in vacuo
9. customThe residual oil was chromatographed on a column of silica gel using
10. additiona mixture of hexanes and diethyl ether (7:3) as eluent