Hydrochloric Acid → 3,5-dimethyl-6-(pyrrolidin-1-yl)-benzofuran-2(3H)-one

HRID 544719Notes

Reaction equation

HRID 544719 reaction equation
[OH:1][C:2]1[CH:7]=[C:6]([N:8]2[CH2:12][CH2:11][CH2:10][CH2:9]2)[C:5]([CH3:13])=[CH:4][C:3]=1[CH:14]([CH3:22])[C:15](N1CCCC1)=[O:16].Cl.C1(N=C=NC2CCCCC2)CCCCC1>C(O)(=O)C>[CH3:22][CH:14]1[C:3]2[CH:4]=[C:5]([CH3:13])[C:6]([N:8]3[CH2:12][CH2:11][CH2:10][CH2:9]3)=[CH:7][C:2]=2[O:1][C:15]1=[O:16]

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 10868DicyclohexylcarbodiimideHCID 544437822-[2-Hydroxy-5-methyl-4-(pyrrolidin-1-yl)-phenyl]-propionic acid pyrrolidide

Product 1

HCID 135769433,5-dimethyl-6-(pyrrolidin-1-yl)-benzofuran-2(3H)-one

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A mixture of 1.8 g (6 mmoles) of 2-[2-hydroxy-5-methyl-4-(pyrrolidin-1-yl)-phenyl]-propionic acid pyrrolidide, 2 ml of glacial acetic acid and 2 ml of concentrated hydrochloric acid is boiled under reflux for 40 minutes. The reaction mixture is concentrated by evaporation in vacuo, water is added to the residue, the pH is adjusted to 5 with dilute sodium hydroxide solution and extraction with ether is carried out 3 times. The combined ethereal extracts are dried over sodium sulphate and concentrated in vacuo to 10 ml. 1.2 g (6 mmoles) of N,N'-dicyclohexylcarbodiimide are added thereto and the mixture is left at room temperature for one hour; the residue is filtered off, subsequently washed with ether, and the filtrate is concentrated by evaporation in vacuo. The residue is chromatographed over silica gel with petroleum ether/ether. Subsequent recrystallisation of the pure fractions from ether/petroleum ether yields 3,5-dimethyl-6-(pyrrolidin-1-yl)-benzofuran-2(3H)-one having a melting point of 68°-69°. The starting material can be obtained, for example, as follows:

Workup

  1. temperatureunder reflux for 40 minutes
  2. concentrationThe reaction mixture is concentrated by evaporation in vacuo, water
  3. additionis added to the residue
  4. extractionthe pH is adjusted to 5 with dilute sodium hydroxide solution and extraction with ether
  5. dry with materialThe combined ethereal extracts are dried over sodium sulphate
  6. concentrationconcentrated in vacuo to 10 ml
  7. filtrationthe residue is filtered off
  8. washsubsequently washed with ether
  9. concentrationthe filtrate is concentrated by evaporation in vacuo
  10. customThe residue is chromatographed over silica gel with petroleum ether/ether
  11. customSubsequent recrystallisation of the pure fractions from ether/petroleum ether

Sources & evidence

ORD record
ord-fee60d3d5f3d4fe8913d7f028b9a6c75
Source dataset
uspto-grants-1984_05
Patent number
US04451462

Reaction notes

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