p-Toluenesulfonic acid monohydrate → racemic methyl 2-(3,4-dichlorophenyl)-2H-chromene-3-carboxylate

HRID 409518Notes

Reaction equation

HRID 409518 reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]([CH:9]2[CH:18]([C:19]([O:21][CH3:22])=[O:20])[CH:17](O)[C:16]3[C:11](=[CH:12][CH:13]=[CH:14][CH:15]=3)[O:10]2)[CH:5]=[CH:6][C:7]=1[Cl:8].O.C1(C)C=CC(S(O)(=O)=O)=CC=1>C1(C)C=CC=CC=1.C(OCC)(=O)C>[Cl:1][C:2]1[CH:3]=[C:4]([CH:9]2[C:18]([C:19]([O:21][CH3:22])=[O:20])=[CH:17][C:16]3[C:11](=[CH:12][CH:13]=[CH:14][CH:15]=3)[O:10]2)[CH:5]=[CH:6][C:7]=1[Cl:8]

Participants

5

Reactant 2

HCID 521998p-Toluenesulfonic acid monohydrateHCID 67155590Methyl 2-(3,4-dichlorophenyl)-4-hydroxychroman-3-carboxylate

Product 1

HCID 67155613racemic methyl 2-(3,4-dichlorophenyl)-2H-chromene-3-carboxylateYield 105.4%

Reagents, catalysts & solvents 2

HCID 1140TolueneSolventHCID 8857Ethyl AcetateSolvent

Procedure

Methyl 2-(3,4-dichlorophenyl)-4-hydroxychroman-3-carboxylate (90 mg) and p-toluenesulfonic acid hydrate (24 mg, 128 μmol) were dissolved in toluene (4.0 mL) and heated to reflux. After 40 min, the solution was cooled to rt, diluted with ethyl acetate, washed with saturated aqueous sodium bicarbonate, dried over sodium sulfate and concentrated under vacuum to provide racemic methyl 2-(3,4-dichlorophenyl)-2H-chromene-3-carboxylate as a white solid (90 mg, 94%). 1H NMR (400 MHz, CDCl3) δ ppm 3.79 (s, 3 H) 6.21 (s, 1 H) 6.81 (d, J=8.1 Hz, 1 H) 6.93 (t, J=7.6 Hz, 1 H) 7.17-7.25 (m, 3 H) 7.35 (d, J=8.6 Hz, 1 H) 7.44 (d, J=2.0 Hz, 1 H) 7.70 (s, 1 H).

Workup

  1. temperatureheated to reflux
  2. washwashed with saturated aqueous sodium bicarbonate
  3. dry with materialdried over sodium sulfate
  4. concentrationconcentrated under vacuum

Sources & evidence

ORD record
ord-09adaddb976b4855b568662ff3f0e7ce
Source dataset
uspto-grants-2014_06
Patent number
US08759390B2

Reaction notes

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