反应详情

0.494 g of 5-Methyl-4-[2-(naphthalen-1-yloxy)-ethyl]-2-phenyl-oxazole (1.50 mmol) was dissolved under argon atmosphere in 6 ml of CH2Cl2 and cooled down to 0°. 0.455 ml of 62% aq. HBr was added, followed by 58 mg of trioxane (0.644 mmol, 1.29 eq.). After 2 h, additional 0.455 ml of 62% aq. HBr was added and stirring continued for totally 5 h under strict temperature control. The reaction mixture was then diluted with CH2Cl2, washed with sat. NaHCO3-sol., the aqueous layer extracted once more with CH2Cl2, the combined organic phases dried over sodium sulfate and evaporated to dryness. This left 0.70 g of the crude title compound which was used as such for the next step. The product is quite unstable and can not be purified by column chromatography on SiO2; it also decomposes readily on TLC-plates.

1. temperaturecooled down to 0°
2. waitcontinued for totally 5 h under strict temperature control
3. washwashed with sat. NaHCO3-sol
4. extraction, the aqueous layer extracted once more with CH2Cl2
5. dry with materialthe combined organic phases dried over sodium sulfate
6. customevaporated to dryness
7. customcan not be purified by column chromatography on SiO2