Water → 6-hydroxy-2-methyl-2H-1-benzopyran-3-carboxaldehyde

HRID 466180Notes

Reaction equation

HRID 466180 reaction equation
[OH:1][C:2]1[CH:9]=[CH:8][C:7]([OH:10])=[CH:6][C:3]=1[CH:4]=O.[CH:11](=[O:15])/[CH:12]=[CH:13]/[CH3:14].C(=O)([O-])[O-].[K+].[K+].O>O1CCOCC1>[OH:10][C:7]1[CH:8]=[CH:9][C:2]2[O:1][CH:13]([CH3:14])[C:12]([CH:11]=[O:15])=[CH:4][C:3]=2[CH:6]=1

Participants

6

Reactant 4

HCID 962WaterHCID 11430Potassium CarbonateHCID 709492,5-DihydroxybenzaldehydeHCID 447466Crotonaldehyde

Product 1

HCID 198156286-hydroxy-2-methyl-2H-1-benzopyran-3-carboxaldehyde

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

The starting material is prepared as follows: A mixture of 2,5-dihydroxybenzaldehyde (5.0 g, 36.2 mmol), crotonaldehyde (3.8 g, 54.3 mmol), and potassium carbonate (10.0 g, 72.4 mmol) in 75 ml of 1,4-dioxane is heated at reflux for 6 hours. The mixture is cooled and poured into water. This is extracted (3×) with dichloromethane, and the combined organic layers are dried (MgSO4) and concentrated to dryness to give 6-hydroxy-2-methyl-2H-1-benzopyran-3-carboxaldehyde as a colored solid. Such is converted to 6-benzyloxy-2-methyl-2H-1-benzopyran-3-carboxaldehyde, m.p. 107°-109° C., which is in turn converted to 3-(N-hydroxyaminomethyl)-6-benzyloxy-2-methyl-2H-1-benzopyran as described above.

Workup

  1. customThe starting material is prepared
  2. temperatureis heated
  3. temperatureat reflux for 6 hours
  4. temperatureThe mixture is cooled
  5. extractionThis is extracted (3×) with dichloromethane
  6. dry with materialthe combined organic layers are dried (MgSO4)
  7. concentrationconcentrated to dryness

Sources & evidence

ORD record
ord-4d28483d548d453398991708eab86c88
Source dataset
uspto-grants-1992_10
Patent number
US05155130

Reaction notes

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