Acetic Anhydride → 5-Chloro-7-hydroxy-3-(4-hydroxyphenyl)-4-oxo-4H-1-benzopyran

HRID 1765403Notes

Reaction equation

HRID 1765403 reaction equation
[Cl:1][C:2]1[CH:7]=[C:6]([OH:8])[CH:5]=[C:4]([OH:9])[C:3]=1[C:10](=[O:19])[CH2:11][C:12]1[CH:17]=[CH:16][C:15]([OH:18])=[CH:14][CH:13]=1.[C:20](OC(=O)C)(=O)C.C([O-])(=O)C.[Na+]>>[Cl:1][C:2]1[C:3]2[C:10](=[O:19])[C:11]([C:12]3[CH:17]=[CH:16][C:15]([OH:18])=[CH:14][CH:13]=3)=[CH:20][O:9][C:4]=2[CH:5]=[C:6]([OH:8])[CH:7]=1

Participants

4

Reactant 3

HCID 7918Acetic AnhydrideHCID 517045Sodium AcetateHCID 211070801-(2-Chloro-4,6-dihydroxyphenyl)-2-(4-hydroxyphenyl)ethanone

Product 1

HCID 99259795-Chloro-7-hydroxy-3-(4-hydroxyphenyl)-4-oxo-4H-1-benzopyran

Conditions

Temperature
140 °C

Procedure

A solution consisting of 1-(2-chloro-4,6-dihydroxyphenyl)-2-(4-hydroxyphenyl)-ethanone (50 mg), acetic anhydride (1.2 mL) and sodium acetate (44 mg) was prepared. The solution was heated at 140° C. for 50 min, cooled to room temperature and stirred for 70 h. The soution was quenched with saturated sodium bicarbonate (10 mL), water (1 mL) and methanol (10 mL). After stirring for 3 h the solution was acidified to pH 5 with saturated potassium diphosphate and extracted with ethyl acetate (3×15 mL). The organics were dried over Na2SO4, filtered and concentrated in vacuo. The resulting yellow oil was diluted with toluene and dehydrated for 1.5 h using a Dean-Starke trap. Chromatography using reverse phase preperative HPLC provided the title compound (18 mg). 1H NMR (DMSO-d6): 11.07 (s br, 1H), 9.46 (s br, 1H), 7.03 (d, 1H, J=8.4 Hz), 6.88 (d, 1H, J=2.4 Hz), 6.79 (s, 1H), 6.78 (d, 2H, J=8.7 Hz), 2.18 (s, 3H); MS: 303 (MH+).

Workup

  1. customwas prepared
  2. temperaturecooled to room temperature
  3. customThe soution was quenched with saturated sodium bicarbonate (10 mL), water (1 mL) and methanol (10 mL)
  4. stirringAfter stirring for 3 h the solution
  5. extractionextracted with ethyl acetate (3×15 mL)
  6. dry with materialThe organics were dried over Na2SO4
  7. filtrationfiltered
  8. concentrationconcentrated in vacuo
  9. additionThe resulting yellow oil was diluted with toluene
  10. waitdehydrated for 1.5 h

Sources & evidence

ORD record
ord-16a8969dc0da4cbd90a376d6021ac3b3
Source dataset
uspto-grants-2007_06
Patent number
US07226945B2

Reaction notes

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