Acetic Anhydride → HCID 23437669, compound

HRID 1871065Notes

Reaction equation

HRID 1871065 reaction equation
[Cl:1][C:2]1[CH:9]=[C:8]([Cl:10])[CH:7]=[C:4]([CH:5]=O)[C:3]=1[OH:11].[C:12](OC(=O)C)(=[O:14])[CH3:13].C(N(CC)CC)C>O>[Cl:10][C:8]1[CH:7]=[C:4]2[C:3](=[C:2]([Cl:1])[CH:9]=1)[O:11][C:12](=[O:14])[CH:13]=[CH:5]2

Participants

5

Reactant 3

HCID 7918Acetic AnhydrideHCID 8471TriethylamineHCID 666603,5-Dichlorosalicylaldehyde

Product 1

HCID 23437669HCID 23437669, compoundYield 72.2%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
50 °C

Procedure

To a 2 L round bottom flask fitted with a mechanical stirrer and condenser was added 3,5-dichlorosalicylaldehyde (200 g, 1.05 mol, 1 equiv.), acetic anhydride (356 g, 3.49 mol) and triethylamine (95.0 g, 0.94 mol, 0.90 equiv.). The reaction solution was heated at reflux overnight. The dark brown reaction mixture was cooled to 50° C. and water (1 L) added with stirring. After one hour the mixture was filtered and the filtrate combined with EtOH (1 L). This mixture was heated to 45° C. for one hour, cooled to room temperature, filtered and the solid (fraction A) washed with EtOH (0.5 L). The combined EtOH solutions were concentrated by rotary evaporation to an oil (fraction B). The solid from fraction A was dissolved in methylene chloride (1.5 L) and the resulting solution passed through a pad of silica gel (1300 mL volume). The resulting dark brown solution was concentrated to an oil that was triturated with hexanes (1.3 L) to give a solid that was isolated by filtration and washed (hexanes) to give substantially pure 6,8-dichlorocoumarin (163 g). A further 31 g of product was obtained by treating the oil, fraction B, in a similar fashion; the oil was dissolved in methylene chloride (0.5 L) passed through a silica pad (0.5 L volume) and triturated with hexanes. The total isolated yield was 194 g or 86% yield of the brown solid.

Workup

  1. customTo a 2 L round bottom flask fitted with a mechanical stirrer and condenser
  2. temperatureThe reaction solution was heated
  3. temperatureat reflux overnight
  4. filtrationAfter one hour the mixture was filtered
  5. temperatureThis mixture was heated to 45° C. for one hour
  6. temperaturecooled to room temperature
  7. filtrationfiltered
  8. washthe solid (fraction A) washed with EtOH (0.5 L)
  9. concentrationThe combined EtOH solutions were concentrated by rotary evaporation to an oil (fraction B)
  10. dissolutionThe solid from fraction A was dissolved in methylene chloride (1.5 L)
  11. concentrationThe resulting dark brown solution was concentrated to an oil that
  12. customwas triturated with hexanes (1.3 L)
  13. customto give a solid
  14. customthat was isolated by filtration
  15. washwashed (hexanes)

Sources & evidence

ORD record
ord-dbac08b1d04a44eb959996545f5d3d2d
Source dataset
uspto-grants-2000_08
Patent number
US06100423

Reaction notes

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