Hydrochloric Acid → 3-Methyl-5-(4-nitrophenoxymethyl)-1,2,4-oxadiazole

Participants

Reaction Steps

A mixture of 4-nitrophenoxyacetic acid (12) (2.25 g, 11.4 mmol), acetamide oxime triethylamine hydrochloride salt (11, 5.85 g, 27.62 mmol), EDCl.HCl (4.37 g, 22.79 mmol) and diisopropylethylamine (7.42 g, 10 mL, 57.40 mmol) in anhydrous tetrahydrofuran (THF) (250 mL) was refluxed for 18 hours. The heterogeneous brown reaction mixture was then quenched with water and extracted with EtOAc (3×300 mL). The combined organic layers were washed successively with aqueous sodium bicarbonate (NaHCO3) and brine. The resulting organic phase was dried over anhydrous Na2SO4 and solvent was removed by using rotary evaporator. The resulting residue was purified by silica gel column chromatography to yield 1.62 g (60%) of the desired product, 3-methyl-5-(4-nitrophenoxymethyl)-1,2,4-oxadiazole (13a) as a white solid. 1H NMR (CDCl3, 300 MHz): δ 8.24 (d, 2H, J=8.8 Hz), 7.08 (d, 2H, J=8.8 Hz), 5.36 (s, 2H), 2.44 (s, 3H); LCMS (m/z): 236 (MH+).

Provenance & Evidence