Phosphorus oxychloride → 4-Chloromethyl-2-cyclohexyl-5-methyl-oxazole

Participants

Reaction Steps

25.1 g of the above prepared 2-cyclohexyl-4,5-dimethyl-oxazole 3-oxide (˜88.8 mmol) was dissolved in 325 ml of CH2Cl2 and treated dropwise with 9.755 ml of POCl3 (1.2 eq.). The reaction mixture was refluxed over night and then quenched by carefully pouring onto crashed ice/3N NaOH. Separation of the layers, additional extraction of the aqueous phase with CH2Cl2, washing with Na2CO3 and water, drying of the combined organic phase over sodium sulfate, evaporation of the solvents, and, finally, flash chromatography (SiO2, hexane/AcOEt=9/1) afforded 4.12 g of the title compound as yellowish oil, exhibiting in the 1H-NMR the typical signal at 4.46 ppm (2H). The other, unstable regioisomer was not isolated.

Provenance & Evidence