[2-(3-cyclopropyl-1-hydroxy-1-trifluoromethyl-prop-2-ynyl)-4-(2-methoxy-ethoxymethoxy)-phenyl]-carbamic Acid Tert-Butyl Ester → 4-Cyclopropylethynyl-6-(2-methoxy-ethoxymethoxy)-4-trifluoromethyl-1,4-dihydro-benzo[d][1,3]oxazin-2-one

Participants

Reaction Steps

To 1.2 g (2.6 mmol) of 7 was added 15 mL of toluene, and the reaction mixture was cooled to 0° to −4° C. under argon atmosphere. To the reaction mixture 1.4 mL (3.5 mmol) of n-butyl lithium (2.5M in hexane) was added, and the resulting reaction mixture was allowed to stir at 0° to −4° C. for 10 minutes, warmed up to room temperature, and allowed to reflux for 1 hour. The reaction mixture was concentrated. Then 20 mL of water was added and the aqueous layer was extracted with 4×20 mL of dichloromethane. Organic layers were combined, dried (Na2SO4), and concentrated. The residue was purified by silica gel flash column chromatography using 20% ethyl acetate in hexane to give 965 mg (2.5 mmol, 96%) of 8 as a light brown oil [LC-MS; M+H 386.1].

Provenance & Evidence