P,P-Diphenylphosphinic azide → 3-[5-(1-Azido-ethyl)-4-methyl-thiophen-2-yl]-5-(3,5-dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazole

Participants

Reaction Steps

Diphenylphosphoryl azide (0.53 ml) and diazabicyclo-[5.4.0]-undec-7-ene (DBU, 0.40 ml) is added to a solution of 1-{5-[5-(3,5-dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazol-3-yl]-3-methyl-thiophen-2-yl}-ethanol (0.87 g) in toluene (9 ml). After 19 hours at room temperature, the reaction is quenched with a saturated aqueous solution of NH4Cl in water. The reaction mixture is extracted three times with ethyl acetate. The organic phases are combined, dried over MgSO4 and concentrated in vacuo. The crude product is purified on a semi-preparative HPLC to yield 3-[5-(1-azido-ethyl)-4-methyl-thiophen-2-yl]-5-(3,5-dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazole (0.64 g) as a yellow oil. MS (HPLC/MS): 449 (MH+). Retention time: 2.45 min.

Provenance & Evidence