Dimethyl acetylenedicarboxylate → HCID 21314612, compound

HRID 236964Notes

Reaction equation

HRID 236964 reaction equation
CO[C:3]([C:5]#[C:6][C:7]([O:9]C)=[O:8])=[O:4].[OH:11][C:12]1[CH:21]=[C:20]([O:22][CH3:23])[CH:19]=[C:18]2[C:13]=1[CH2:14][CH2:15][C:16]([CH3:25])([CH3:24])[O:17]2.[OH-].[Na+]>O1CCOCC1.O.OS(O)(=O)=O>[CH3:23][O:22][C:20]1[C:21]2[C:3](=[O:4])[CH:5]=[C:6]([C:7]([OH:9])=[O:8])[O:11][C:12]=2[C:13]2[CH2:14][CH2:15][C:16]([CH3:25])([CH3:24])[O:17][C:18]=2[CH:19]=1

Participants

7

Reactant 3

HCID 12980Dimethyl acetylenedicarboxylateHCID 14798Sodium HydroxideHCID 11041970HCID 11041970, compound

Product 1

HCID 21314612HCID 21314612, compoundYield 23.3%

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 1118Sulfuric AcidSolventHCID 312751,4-DioxaneSolvent

Procedure

To a solution of dimethylacetylenedicarboxylate (7.5 g) in dioxan (100 ml) containing `Triton 8` (10 drops) was added 5-hydroxy-7-methoxy-2,2-dimethylchroman (10.0 g) and the resulting mixture was warmed on a steam bath for 2 hours. A solution of sodium hydroxide (4.0 g) in water (20 ml) was added and heating was continued for 2 hours more. The organic solvent was removed and water (50 ml) was added to the residue and the mixture was acidified to give an oil which was extracted into ethylacetate. This solution was dried over MgSO4, filtered and the filtrate was evaporated to dryness. The oil so obtained was dissolved in concentrated H2SO4 (50 ml) and the solution was stirred at room temperature for 30 minutes, poured into ice and extracted with ethyl acetate. This solution was washed with water, dried (MgSO4), filtered and evaporated to dryness. The oil so produced was triturated with ethyl acetate, cooled to 0°, and the solid produced was filtered and dried. The solid was crystallised from ethanol to give 8,9-dihydro-5-methoxy-8,8-dimethyl-4-oxo-4H,10H-benzo[1,2-b:3,4-b']dipyran-2-carboxylic acid as a white solid (3.4 g, 23%) mp 225°-6°.

Workup

  1. temperaturethe resulting mixture was warmed on a steam bath for 2 hours
  2. temperatureheating
  3. customThe organic solvent was removed
  4. additionwater (50 ml) was added to the residue
  5. customto give an oil which
  6. extractionwas extracted into ethylacetate
  7. dry with materialThis solution was dried over MgSO4
  8. filtrationfiltered
  9. customthe filtrate was evaporated to dryness
  10. customThe oil so obtained
  11. additionpoured into ice
  12. extractionextracted with ethyl acetate
  13. washThis solution was washed with water
  14. dry with materialdried (MgSO4)
  15. filtrationfiltered
  16. customevaporated to dryness
  17. customThe oil so produced
  18. customwas triturated with ethyl acetate
  19. temperaturecooled to 0°
  20. customthe solid produced
  21. filtrationwas filtered
  22. customdried
  23. customThe solid was crystallised from ethanol

Sources & evidence

ORD record
ord-4eddaecb416c4ebbabaff262d2434eb5
Source dataset
uspto-grants-1979_06
Patent number
US04159273

Reaction notes

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