p-Toluenesulfonic acid monohydrate → HCID 54009394, compound

HRID 327966Notes

Reaction equation

HRID 327966 reaction equation
[CH2:1]([O:3][C:4](=[O:21])[CH2:5][CH2:6][CH2:7][CH2:8][O:9][C:10]1[CH:11]=[CH:12][C:13]2[O:18][C:17](=[O:19])[CH2:16][CH2:15][C:14]=2[CH:20]=1)[CH3:2].[OH2:22].[C:23]1(C)C=CC(S(O)(=O)=O)=C[CH:24]=1>C(O)C>[CH2:23]([O:19][C:17](=[O:22])[CH2:16][CH2:15][C:14]1[CH:20]=[C:10]([O:9][CH2:8][CH2:7][CH2:6][CH2:5][C:4]([O:3][CH2:1][CH3:2])=[O:21])[CH:11]=[CH:12][C:13]=1[OH:18])[CH3:24]

Participants

4

Reactant 2

HCID 521998p-Toluenesulfonic acid monohydrateHCID 54109816HCID 54109816, compound

Product 1

HCID 54009394HCID 54009394, compoundYield 61.4%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

A mixture of 1.5 g (9.15 mmol) of 6-hydroxy-3,4-dihydrocoumarin, 2.1 g (10 mmol) of ethyl 5-bromovalerate, 4.16 g (30 mmol) of anhydrous, granular potassium carbonate, and 15 mL of N,N-dimethylformamide was stirred at room temperature, for 23 hr. The resulting dark-brown slurry was diluted with ether and washed with water and brine. Completion of the usual work-up gave 2.32 of a red-orange oil which was chromatographed on 50 g of silica gel. Elution with 1:1 hexane-ether gave 2.03 g of a yellow oil which was a mixture of the desired 5-[(3,4-dihydro-2-oxo-2H-1-benzopyran-6-yl)oxy]pentanoic acid ethyl ester and an impurity. This material was dissolved in 25 mL of ethanol and 52 mg of p-toluenesulfonic acid monohydrate was added. The resulting solution was stirred and refluxed for 22.5 hr and then concentrated in vacuo. The residue was dissolved in ether and the ether solution was processed in the usual manner giving an amber oil. This material was chromatographed on 50 g of silica gel. Elution with 1:1 hexane-ether afforded 1.90 g (61.4%) of 5-(5-ethoxy-5-oxopentyloxy)-2-hydroxybenzenepropanoic acid ethyl ester as a pale-yellow oil.

Workup

  1. temperaturerefluxed for 22.5 hr
  2. concentrationconcentrated in vacuo
  3. dissolutionThe residue was dissolved in ether
  4. customgiving an amber oil
  5. customThis material was chromatographed on 50 g of silica gel
  6. washElution with 1:1 hexane-ether

Sources & evidence

ORD record
ord-3110d929ba7a47948699bc2a01caab78
Source dataset
uspto-grants-1993_12
Patent number
US05273999

Reaction notes

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