Réaction #566301

Équation de réaction

HBr

HBr

5-Methyl-4-[2-(naphthalen-1-yloxy)-ethyl]-2-phenyl-oxazole

trioxane

→

4-[2-(4-Bromomethyl-naphthalen-1-yloxy)-ethyl]-5-methyl-2-phenyl-oxazole

Solvants

CH2Cl2

CH2Cl2

Conditions de réaction

Traitement

1. 1
   Températurecooled down to 0°
2. 2
   workup.WAITcontinued for totally 5 h under strict temperature control
3. 3
   Lavagewashed with sat. NaHCO3-sol
4. 4
   Extraction, the aqueous layer extracted once more with CH2Cl2
5. 5
   Séchagethe combined organic phases dried over sodium sulfate
6. 6
   Autreevaporated to dryness
7. 7
   Autrecan not be purified by column chromatography on SiO2

Mode opératoire

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.

Source