Resorcinol → 7-hydroxy-2,3-dihydro-4H-chromen-4-one

HRID 1904547Notes

Reaction equation

HRID 1904547 reaction equation
[Al+3].[Cl-].[Cl-].[Cl-].[C:5]1([CH:12]=[CH:11][CH:10]=[C:8]([OH:9])[CH:7]=1)[OH:6].Cl[CH:14]([CH3:18])[C:15](Cl)=[O:16]>[N+](C1C=CC=CC=1)([O-])=O>[OH:6][C:5]1[CH:12]=[CH:11][C:10]2[C:15](=[O:16])[CH2:14][CH2:18][O:9][C:8]=2[CH:7]=1

Participants

5

Reactant 3

HCID 5054ResorcinolHCID 1110192-Chloropropionyl chlorideHCID 6451240Aluminum(III) Chloride

Product 1

HCID 108558177-hydroxy-2,3-dihydro-4H-chromen-4-oneYield 25%

Reagents, catalysts & solvents 1

HCID 7416NitrobenzeneSolvent

Procedure

Under ice cooling, AlCl3 (3 molar equivalent) was added little by little to a solution composed of 11 g of resorcinol, 12.7 g of 2-chloropropionyl chloride and 120 ml of nitrobenzene. After the addition, the mixture was heated at 40° to 50° C. for 4 hours with stirring. The reaction mixture was worked up and purified in a customary manner to give 4.1 g of 2,3-dihydro-7-hydroxy-4-oxobenzopyran. The resulting compound was benzylated, reduced with sodium borohydride in methanol, and then methylated with methyl iodide in tetrahydrofuran in the presence of sodium hydride. In a customary manner, the methylated product was hydrogenated to give 1.7 g (yield 9.4%) of the desired product as a colorless liquid.

Workup

  1. additionAfter the addition
  2. temperaturethe mixture was heated at 40° to 50° C. for 4 hours
  3. custompurified in a customary manner

Sources & evidence

ORD record
ord-99415e23a7f242ba9949e5fc9f1b8cf9
Source dataset
uspto-grants-1989_06
Patent number
US04838924

Reaction notes

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