Ethanol → Ethyl-6-chloro-7-hydroxy-3,4-dihydro-2H-chromene-4-carboxylate

HRID 1626407Notes

Reaction equation

HRID 1626407 reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][C:11]=1[OH:12])[O:8][CH2:7][CH2:6][CH:5]2[C:13]([OH:15])=[O:14].S(=O)(=O)(O)O.[CH2:21](O)[CH3:22]>>[Cl:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][C:11]=1[OH:12])[O:8][CH2:7][CH2:6][CH:5]2[C:13]([O:15][CH2:21][CH3:22])=[O:14]

Participants

4

Reactant 3

HCID 702EthanolHCID 1118Sulfuric AcidHCID 670804286-Chloro-7-hydroxychroman-4-carboxylic acid

Product 1

HCID 53393319Ethyl-6-chloro-7-hydroxy-3,4-dihydro-2H-chromene-4-carboxylateYield 41%

Conditions

Temperature
60 °C

Procedure

To a solution of 6-chloro-7-hydroxychroman-4-carboxylic acid (99 g, 433 mmol) in ethanol (650 mL) was added sulfuric acid (1.2 mL) and the reaction was stirred at 60° C. for 24 hours. The reaction was cooled to ambient temperature and the resulting solids were removed by filtration and discarded. The filtrate was diluted with ethyl acetate (700 mL), washed with water, dried over magnesium sulfate and concentrated. The crude material was purified by silica gel column chromatography eluting with a solvent system of 20% ethyl acetate/hexanes to give ethyl 6-chloro-7-hydroxychroman-4-carboxylate (46 g, 41%).

Workup

  1. temperatureThe reaction was cooled to ambient temperature
  2. customthe resulting solids were removed by filtration
  3. additionThe filtrate was diluted with ethyl acetate (700 mL)
  4. washwashed with water
  5. dry with materialdried over magnesium sulfate
  6. concentrationconcentrated
  7. customThe crude material was purified by silica gel column chromatography
  8. washeluting with a solvent system of 20% ethyl acetate/hexanes

Sources & evidence

ORD record
ord-0b2ebaa6bf96433a809088c543f9565c
Source dataset
uspto-grants-2014_07
Patent number
US08785445B2

Reaction notes

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