Phosphorus oxychloride → 5-tert-Butyl-2-(chloromethyl)-1,3-oxazole

Temperature

105 °C

N-Chloroacetyl-1-amino-3,3-dimethyl-2-butanone (180.13 g, 0.9398 mol, 1 eq) was combined with phosphorus oxychloride (262 mL, 2.8109 mol, 3 eq) under N2. The reaction mixture was heated at 105° C. for 1 h. The mixture was cooled to rt and then quenched with 1.3 kg of ice. The aqueous phase was extracted with ethyl acetate (1 L, then 2×500 mL). The organic extracts were washed with saturated aqueous NaHCO3 (4×1 L) which was back-extracted several times with ethyl acetate. The organic phases were combined, washed with saturated aqueous NaHCO3 (500 mL) followed by saturated aqueous NaCl (300 mL), dried over MgSO4, and concentrated in vacuo to give a brown oil. The crude material was distilled under high vacuum at 100° C. to provide 155.92 g (96%) of 5-t-butyl-2-chloromethyloxazole. HPLC R.T.=3.62 min (Phenomenex 5 μm C18 column 4.6×50 mm, 10-90% aqueous methanol over 4 minutes containing 0.2% phosphoric acid, 4 mL/min, monitoring at 220 nm).

1. temperatureThe mixture was cooled to rt
2. customquenched with 1.3 kg of ice
3. extractionThe aqueous phase was extracted with ethyl acetate (1 L
4. washThe organic extracts were washed with saturated aqueous NaHCO3 (4×1 L) which
5. extractionwas back-extracted several times with ethyl acetate
6. washwashed with saturated aqueous NaHCO3 (500 mL)
7. dry with materialdried over MgSO4
8. concentrationconcentrated in vacuo
9. customto give a brown oil
10. distillationThe crude material was distilled under high vacuum at 100° C.

ORD record

ord-3e3157c5c6774dd39305457fa5880b10

Source dataset

uspto-grants-2003_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06515004B1