1-(5-Chloro-2-hydroxyphenyl)-3-(4-chlorophenyl)-2-propen-1-one → 6-Chloro-2-(4-chlorophenyl)-2H-1-benzopyran

HRID 1462956Notes

Reaction equation

HRID 1462956 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([CH:8]=[CH:9][C:10]([C:12]2[CH:17]=[C:16]([Cl:18])[CH:15]=[CH:14][C:13]=2[OH:19])=O)=[CH:4][CH:3]=1.[BH4-].[Na+]>C(O)C>[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([CH:8]2[CH:9]=[CH:10][C:12]3[C:13](=[CH:14][CH:15]=[C:16]([Cl:18])[CH:17]=3)[O:19]2)=[CH:4][CH:3]=1

Participants

4

Reactant 2

HCID 978941-(5-Chloro-2-hydroxyphenyl)-3-(4-chlorophenyl)-2-propen-1-oneHCID 4311764Sodium borohydride

Product 1

HCID 162052936-Chloro-2-(4-chlorophenyl)-2H-1-benzopyranYield 55.5%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

4,5'-Dichloro-2'-hydroxychalcone (7.32 g) was dissolved in ethanol (100 ml) and sodium borohydride (1.89 g) added in small portions. The reaction mixture was stirred for 1 hr at room temperature, evaporated to dryness, and diluted with water. The precipitated solid was filtered off, washed with water, and heated with acetic acid (100 ml) on the steam bath for 2 hr. The acetic acid was evaporated the residue dissolved in dichloromethane, and the solution washed sequentially with water, saturated sodium bicarbonate solution, and water, dried and evaporated. The residue was chromatographed on alumina, eluting with toluene, to give 4',6-dichloroflav-3-ene (3.84 g) as a colourless oil, identified by n.m.r. spectroscopy.

Workup

  1. customevaporated to dryness
  2. additiondiluted with water
  3. filtrationThe precipitated solid was filtered off
  4. washwashed with water
  5. temperatureheated with acetic acid (100 ml) on the steam bath for 2 hr
  6. customThe acetic acid was evaporated the residue
  7. dissolutiondissolved in dichloromethane
  8. washthe solution washed sequentially with water, saturated sodium bicarbonate solution, and water
  9. customdried
  10. customevaporated
  11. customThe residue was chromatographed on alumina
  12. washeluting with toluene

Sources & evidence

ORD record
ord-45eb40cb01374ab890d9215ca8fb9483
Source dataset
uspto-grants-1984_07
Patent number
US04461907

Reaction notes

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