Aldoxime → Methyl 3-methylisoxazole-5-carboxylate

To a solution of N-chlorosuccinimide (2.67 g, 20 mmol) and pyridine (0.1 mL) in chloroform (18 mL), was added, portionwise, acetaldehyde oxime (1.18 g, 20 mmol), at about 5° C. After complete addition the mixture was stirred at rt for about 10 min and then methyl propiolate (2.22 mL, 25 mmol) was added. Subsequently, a solution of triethylamine (2.92 mL, 21 mmol) in chloroform (3 mL) was added dropwise, at such a rate that the temperature was maintained between 15 and 18° C. After complete addition the mixture was stirred at about 18° C. for about 20 min, then water (15 mL) was added. The layers were separated and the organic layer was washed with water (15 mL), dried (MgSO4), filtered, and concentrated in vacuo. The residue was treated with diethyl ether (20 mL) and the formed precipitate was collected by filtration and dried to give methyl 3-methylisoxazole-5-carboxylate (1.75 g, 12.4 mmol, 62%) as a brown solid which was used as such: 1H-NMR (CDCl3, Bruker 400 MHz) 2.38 (3 H, s); 3.96 (3 H, s); 6.80 (1 H, s).

1. customat about 5° C
2. additionAfter complete addition the mixture
3. temperatureat such a rate that the temperature was maintained between 15 and 18° C
4. additionAfter complete addition the mixture
5. stirringwas stirred at about 18° C. for about 20 min
6. customThe layers were separated
7. washthe organic layer was washed with water (15 mL)
8. dry with materialdried (MgSO4)
9. filtrationfiltered
10. concentrationconcentrated in vacuo
11. additionThe residue was treated with diethyl ether (20 mL)
12. filtrationthe formed precipitate was collected by filtration
13. customdried

ORD record

ord-2882c6c450404dd0ad67f6eaaac47208

Source dataset

uspto-grants-2015_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09150592B2