Hydrochloric Acid → Coumaranone

HRID 636840Notes

Reaction equation

HRID 636840 reaction equation
[OH-].[K+].[O:3]1[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[C:5](=[O:12])[CH:4]1C(OC)=O.O1C2C=CC=CC=2C(=O)C1C(OCC)=O.Cl>O.C(O)C>[O:3]1[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[C:5](=[O:12])[CH2:4]1

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 14797Potassium HydroxideHCID 4104819Ethyl 3-oxo-2,3-dihydrobenzofuran-2-carboxylateHCID 117900262-Benzofurancarboxylic acid, 2,3-dihydro-3-oxo-, methyl ester

Product 1

HCID 23556CoumaranoneYield 94%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 962WaterSolvent4×

Conditions

Temperature
20 °C

Procedure

A solution is prepared from 8.2 l of water and 8262 g (125.4 mol) of potassium hydroxide (85% pure), 12.5 l of ethanol are added at 50-60° C. and 9079 g of the water-moist mixture, obtained in the 1st stage described above, of methyl benzofuran-3-one-2-carboxylate and ethyl benzofuran-3-one-2-carboxylate (24.79 mol in total) are then added. The mixture is heated under reflux for 45 minutes and 7.3 l of water are then added. This solution is cooled to 20° C. and introduced into a mixture, heated at 55° C., of 17.5 l of concentrated hydrochloric acid and 20 l water in the course of 60 minutes, vigorous evolution of gas taking place. Residues of the alkaline solution are rinsed out with 3 l of water and also introduced into the hydrochloric acid. The mixture is stirred at 60° C. for a further 30 minutes (end of the evolution of gas) and cooled to 20° C. The product is filtered off with suction, rinsed with 6 l of water and dried at 35° c. in a vacuum drying cabinet. 3250 g (94% of theory) of benzofuran-3-one are obtained. HPLC: logP=1.26.

Workup

  1. additionare added at 50-60° C.
  2. additionare then added
  3. temperatureThe mixture is heated
  4. temperatureunder reflux for 45 minutes
  5. additionintroduced into a mixture
  6. washResidues of the alkaline solution are rinsed out with 3 l of water
  7. additionalso introduced into the hydrochloric acid
  8. temperaturecooled to 20° C
  9. filtrationThe product is filtered off with suction
  10. washrinsed with 6 l of water
  11. customdried at 35° c
  12. customin a vacuum drying cabinet

Sources & evidence

ORD record
ord-2ef2d24c39ab4c21b48f9f260c02e4eb
Source dataset
uspto-grants-2001_02
Patent number
US06194590B1

Reaction notes

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