Thionyl Chloride → 6-methoxy-3,4-dihydro-2H-1-benzopyran-4-one

HRID 428177Notes

Reaction equation

HRID 428177 reaction equation
[CH3:1][O:2][C:3]1[CH:14]=[CH:13][C:6]([O:7][CH2:8][CH2:9][C:10]([OH:12])=O)=[CH:5][CH:4]=1.S(Cl)(Cl)=O.[Cl-].[Al+3].[Cl-].[Cl-]>C1(C)C=CC=CC=1>[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[C:6](=[CH:13][CH:14]=1)[O:7][CH2:8][CH2:9][C:10]2=[O:12]

Participants

5

Reactant 3

HCID 24386Thionyl ChlorideHCID 2904783-(4-Methoxyphenoxy)propionic acidHCID 6451240Aluminum(III) Chloride

Product 1

HCID 46121686-methoxy-3,4-dihydro-2H-1-benzopyran-4-one

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

Cyclisation is carried out on the acid chloride generated starting from the acid. Heating the acid obtained in Step B (500 mg:2.55 mmol) at reflux of toluene (20 ml) for 3 hours in the presence of thionyl chloride (0.56 ml:7.65 mmol:3 eq.) allows easy access to the acid chloride. The solvent and also the excess reagent are removed by concentrating the resulting yellow solution under reduced pressure. The dry residue is then taken up in 20 ml of anhydrous dichloromethane; aluminium chloride (465.9 mg:3.49 mmol:1.5 eq.) is then introduced cautiously. The reaction mixture is hydrolysed in the cold state after 1 hour of stirring at ambient temperature. The product is extracted, washed with water and then purified on a silica column (AcOEt/PE 3/7).

Workup

  1. customThe solvent and also the excess reagent are removed
  2. concentrationby concentrating the resulting yellow solution under reduced pressure
  3. extractionThe product is extracted
  4. washwashed with water
  5. custompurified on a silica column (AcOEt/PE 3/7)

Sources & evidence

ORD record
ord-5cdc4f4fb41a40a28b44b2fb99de73aa
Source dataset
uspto-grants-2001_11
Patent number
US06313160B1

Reaction notes

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