Oxalyl chloride → Ammonia

Oxalyl chloride (5.16 mL, 59.2 mmol) was added to a solution of β-(3,5-dimethyl-4-isoxazolyl)propionic acid (J. Org. Chem. 59(10); 1994; 2882) (2.5 g, 14.8 mmol) in dichloromethane (50 mL) and N,N-dimethylformamide (1 drop), and the solution was stirred at room temperature for 30 minutes. The mixture was concentrated under reduced pressure and the residue was azeotroped with dichloromethane (5×) to provide a brown liquid. This was dissolved in dichloromethane (25 mL), and tert-butyl carbazate (2.93 g, 22.2 mmol) was added portionwise. The mixture was diluted with further dichloromethane (23 mL) and the reaction was stirred for 18 hours at room temperature. The mixture was concentrated under reduced pressure, the residue was suspended in dichloromethane, the resulting precipitate was filtered off and the filtrate was evaporated under reduced pressure. The residue was purified by column chromatography on silica gel using an elution gradient of dichloromethane:methanol:0.88 ammonia (95:5:0.5 to 90:10:1) to provide the title compound as an oil, 3.08 g.

1. concentrationThe mixture was concentrated under reduced pressure
2. customthe residue was azeotroped with dichloromethane (5×)
3. customto provide a brown liquid
4. stirringthe reaction was stirred for 18 hours at room temperature
5. concentrationThe mixture was concentrated under reduced pressure
6. filtrationthe resulting precipitate was filtered off
7. customthe filtrate was evaporated under reduced pressure
8. customThe residue was purified by column chromatography on silica gel using an elution gradient of dichloromethane

ORD record

ord-8a2e53c658ff4fa4a615632e52a90fd3

Source dataset

uspto-grants-2010_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07745630B2