Hydrochloric Acid → Coumarin, 8-acetyl-7-hydroxy-4-methyl-

HRID 2082950Notes

Reaction equation

HRID 2082950 reaction equation
[CH3:1][C:2]1[C:11]2[C:6](=[CH:7][C:8]([OH:12])=[CH:9][CH:10]=2)[O:5][C:4](=[O:13])[CH:3]=1.[Cl-].[Al+3].[Cl-].[Cl-].[Cl-].[Na+].Cl.[C:21](Cl)(=[O:23])[CH3:22]>O>[CH3:1][C:2]1[C:11]2[C:6](=[C:7]([C:21](=[O:23])[CH3:22])[C:8]([OH:12])=[CH:9][CH:10]=2)[O:5][C:4](=[O:13])[CH:3]=1

Participants

7

Reactant 5

HCID 313Hydrochloric Acid2×HCID 5234Sodium ChlorideHCID 6367Acetyl chlorideHCID 52805674-MethylumbelliferoneHCID 6451240Aluminum(III) Chloride

Product 1

HCID 5324648Coumarin, 8-acetyl-7-hydroxy-4-methyl-

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
150 °C

Procedure

4-Methyl-7-hydroxy-coumarin (26.4g), aluminum chloride (76.1g) and sodium chloride (9.5g) were placed in a flask and shaken to effect reasonable mixing. The flask was then immersed in an oil bath, and the temperature raised to 150° C. Hydrogen chloride evolution commenced at about 100°-110° C. After maintaining the temperature at 150° C for 15 minutes, the melt produced was heated to 160° C and stirred until evolution of hydrogen chloride ceased. Stirring was continued while acetyl chloride (11.8 ml) was added to the melt over a period of about 30 minutes. After maintaining the melt at 160° to 165° C for a further 15 minutes, it was poured with stirring into water (1000 ml). The solid produced was filtered off, washed free of chloride, and dried. On analysis, it was found that the solid contained about 70% by weight of 4-methyl-7-hydroxy-8-acetyl-coumarin and about 30% by weight of 4-methyl-7-hydroxy-6-acetyl-coumarin. The latter isomer was removed by recrystallisation of the product three times from 85% IMS to yield 20.4g of a 4-methyl-7-hydroxy-8-acetyl-coumarin, mpt 167°-169° C.

Workup

  1. customThe flask was then immersed in an oil bath
  2. customcommenced at about 100°-110° C
  3. temperatureAfter maintaining the temperature at 150° C for 15 minutes
  4. customthe melt produced
  5. temperaturewas heated to 160° C
  6. stirringStirring
  7. additionwas added to the melt over a period of about 30 minutes
  8. temperatureAfter maintaining the melt at 160° to 165° C for a further 15 minutes
  9. additionit was poured
  10. customThe solid produced
  11. filtrationwas filtered off
  12. washwashed free of chloride
  13. customdried
  14. customThe latter isomer was removed by recrystallisation of the product three times from 85% IMS

Sources & evidence

ORD record
ord-f33b6f7f69d540c9941aa8922a0a8036
Source dataset
uspto-grants-1978_04
Patent number
US04083857

Reaction notes

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