p-Toluenesulfonic acid → 2-oxo-2H-chromene-3-carboxylic acid 3-oxo-butyl ester

HRID 592127Notes

Reaction equation

HRID 592127 reaction equation
[O:1]1[C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[CH:5]=[C:4]([C:12]([OH:14])=[O:13])[C:2]1=[O:3].C1(C)C=CC(S(O)(=O)=O)=CC=1.O[CH2:27][CH2:28][C:29](=[O:31])[CH3:30]>>[O:31]=[C:29]([CH3:30])[CH2:28][CH2:27][O:13][C:12]([C:4]1[C:2](=[O:3])[O:1][C:11]2[C:6]([CH:5]=1)=[CH:7][CH:8]=[CH:9][CH:10]=2)=[O:14]

Participants

4

Reactant 3

HCID 6101p-Toluenesulfonic acidHCID 10752Coumarin-3-Carboxylic AcidHCID 1115094-Hydroxy-2-Butanone

Product 1

HCID 867104572-oxo-2H-chromene-3-carboxylic acid 3-oxo-butyl ester

Procedure

Coumarin-3-carboxylic acid (25.0 g, 131 mmol) is dissolved into 100 mL of 4-hydroxy-2-butanone with ˜0.050 g of para-toluene sulfonic acid in a round bottom flask equipped with a stir bar and condenser packed with molecular sieves. The pressure is reduced to ˜15 mmHg and the system is refluxed for 10 hours. The solvents are removed by rotary evaporation. The solid organic residue is purified by column chromatography using 3:1 ethyl acetate:hexanes to yield 2-oxo-2H-chromene-3-carboxylic acid 3-oxo-butyl ester.

Workup

  1. customequipped with a stir bar and condenser
  2. temperaturethe system is refluxed for 10 hours
  3. customThe solvents are removed by rotary evaporation
  4. customThe solid organic residue is purified by column chromatography

Sources & evidence

ORD record
ord-e5b6d0605b6845219bc68699fc8a1ef8
Source dataset
uspto-grants-2016_01
Patent number
US09238712B2

Reaction notes

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