Water → (r)-4-Hydroxy-6-chloro-8-difluoromethoxychroman-4-yl carboxylic acid

Temperature

75 °C

To a solution of (S)- or (R)-4-hydroxy4-hydroxymethyl-6-chloro-8-difluoromethoxychromane (3.2 g, 11.4 mmol, from step (vii) above) in acetone (25 mL) was added non-ionized water (110 mL), then sodium hydrogencarbonate (2.13 g, 22.2 mmol) and Pt/C 5%, 58% water (2.13 g). A stream of air was bubbled through the solution with stirring at 75° C. (oil-bath) overnight. The solution was filtered through Celite and the filter-cake was washed with water. The acetone-water solution was acidified (HCl, 2M) to pH 2, saturated with NaCl and extracted with EtOAc (3×). The combined ethyl acetate phases were washed with water (2×) and with brine, then dried (Na2SO4) and concentrated. The residue was dissolved in ether. The ether solution was washed with water (3×) and concentrated, yielding 2.4 g (71%) of the sub-title compound.

1. customA stream of air was bubbled through the solution
2. filtrationThe solution was filtered through Celite
3. washthe filter-cake was washed with water
4. extractionsaturated with NaCl and extracted with EtOAc (3×)
5. washThe combined ethyl acetate phases were washed with water (2×) and with brine
6. dry with materialdried (Na2SO4)
7. concentrationconcentrated
8. dissolutionThe residue was dissolved in ether
9. washThe ether solution was washed with water (3×)
10. concentrationconcentrated

ORD record

ord-9644ab07b64942d4aeb532899a601541

Source dataset

uspto-grants-2007_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07241757B2