Hydrochloric Acid → 5-Methylisoxazole-3-carbonyl chloride

Ethyl 5-methylisoxazole-3-carboxylate (500 mg, 3.22 mmol) was suspended in MeOH-THF-H2O (20 mL, 1:1:1) and lithium hydroxide monohydrate (1.35 g, 32.2 mmol) was added. The reaction mixture was stirred for 16 h at room temperature, and acidified with 1N HCl. The crude product was extracted with ethyl acetate, and ethyl acetate layer was dried (Na2SO4) and solvent evaporated. The white solid thus obtained, was suspended in dichloromethane (30 mL) and treated with thionyl chloride (2.35 mL, 32.3 mmol) at reflux for 6 hr. The reaction mixture was evaporated, and the residue was dissolved in hexane-ethyl acetate mixture (100 mL, 6:4) and quickly filtered through a short silica plug. On evaporation of solvent, 5-methylisoxazole-3-carbonyl chloride was obtained as a colorless syrup (330 mg, 70%).

1. extractionThe crude product was extracted with ethyl acetate, and ethyl acetate layer
2. dry with materialwas dried (Na2SO4) and solvent
3. customevaporated
4. customThe white solid thus obtained
5. temperatureat reflux for 6 hr
6. customThe reaction mixture was evaporated
7. dissolutionthe residue was dissolved in hexane-ethyl acetate mixture (100 mL, 6:4)
8. filtrationquickly filtered through a short silica plug
9. customOn evaporation of solvent

ORD record

ord-6d33435c9354401db2e3c82d88481c91

Source dataset

uspto-grants-2011_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08030487B2