Chromanone → Benzopyran

HRID 542222

Reaction equation

HRID 542222 reaction equation
[CH:1]1[CH:2]=[CH:3][C:4]2[O:11][CH2:10][CH2:9][C:7](=O)[C:5]=2[CH:6]=1.[H-].[Al+3].[Li+].[H-].[H-].[H-]>C(OCC)C>[O:11]1[C:4]2[C:5](=[CH:6][CH:1]=[CH:2][CH:3]=2)[CH:7]=[CH:9][CH2:10]1

Participants

4

Reactant 2

HCID 68110ChromanoneHCID 21226445Aluminium lithium hydride

Product 1

HCID 9211Benzopyran

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent

Procedure

The chromanone was dissolved in 400 ml. of dry ethyl ether, and 2.5 gm of lithium aluminum hydride was added in portions. The reaction was refluxed for 2 hours and then allowed to come to room temperature. The excess lithium aluminum hydride was destroyed by dropwise addition of water and 150 ml. of 4N HCl was added slowly to the reaction mixture. Stirring was continued for 15 minutes. The reaction mixture was extracted with ether and washed successively with 100 ml. of water, 100 ml. 5% sodium carbonate solution and 100 ml. saturated NaCl solution. The ethereal extract was dried over anhydrous sodium sulfate. Removal of the ether in vacuo gave 15.6 g of crude chromene.

Workup

  1. temperatureThe reaction was refluxed for 2 hours
  2. customto come to room temperature
  3. customThe excess lithium aluminum hydride was destroyed by dropwise addition of water and 150 ml
  4. additionof 4N HCl was added slowly to the reaction mixture
  5. extractionThe reaction mixture was extracted with ether
  6. washwashed successively with 100 ml
  7. extractionThe ethereal extract
  8. dry with materialwas dried over anhydrous sodium sulfate
  9. customRemoval of the ether in vacuo

Sources & evidence

ORD record
ord-d0b784848fe449c8a22679f9a58c46d2
Source dataset
uspto-grants-1987_04
Patent number
US04656189

Linked notes

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