Boron Trichloride → 4-Acetylamino-5-(5-chloro-2,4-dihydroxy-phenyl)-isoxazole-3-carboxylic acid ethylamide

Temperature

0 °C

A solution of 4-acetylamino-5-(2,4-bis-benzyloxy-5-chloro-phenyl)-isoxazole-3-carboxylic acid ethylamide (0.35 mmol) in DCM (10 ml) under inert atmosphere was cooled at 0° C. and BCl3 in DCM (1M, 1.05 mmol, 1.05 ml) was added dropwise. The reaction was stirred at 0° C. for 20 min, the cooling bath was then removed and the mixture stirred for a further 50 min. The mixture was cooled back and then quenched by cautious addition of saturated aqueous NaHCO3 solution (20 ml). The DCM was removed under vacuo and water (20 ml) was added. The mixture was then extracted with EtOAc (200 ml). The phases were separated and the organic phase was washed with water (2×30 ml), sat. aqueous NaCl solution (50 ml) and then dried and filtered. Solvent was removed under vacuo and the crude product purified by flash chromatography on silica gel.

1. customthe cooling bath was then removed
2. stirringthe mixture stirred for a further 50 min
3. temperatureThe mixture was cooled back
4. customquenched by cautious addition of saturated aqueous NaHCO3 solution (20 ml)
5. customThe DCM was removed under vacuo and water (20 ml)
6. additionwas added
7. extractionThe mixture was then extracted with EtOAc (200 ml)
8. customThe phases were separated
9. washthe organic phase was washed with water (2×30 ml), sat. aqueous NaCl solution (50 ml)
10. customdried
11. filtrationfiltered
12. customSolvent was removed under vacuo
13. customthe crude product purified by flash chromatography on silica gel

ORD record

ord-b50ae7f777d841c3bba10527681ca7e4

Source dataset

uspto-grants-2013_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08383616B2