Benzopyran → Chroman

HRID 965835Notes

Reaction equation

HRID 965835 reaction equation
[O:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH:4]=[CH:3][CH2:2]1>[Pd].C(O)(=O)C>[O:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH2:4][CH2:3][CH2:2]1

Participants

4

Reactant 1

HCID 9211Benzopyran

Product 1

HCID 136319ChromanYield 98.6%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 176Acetic AcidSolvent

Procedure

A mixture of chromene (see: Chatterjea, J. Indian Chem. Soc. 1959, 35, 78.) (5.00 g, 37.8 mmol) and 10% palladium on activated carbon (250 mg) in glacial acetic acid (100 mL) is placed in a Parr bottle. The mixture is shaken under an atmosphere of hydrogen (45 psi) for 3 h at rt. The mixture is filtered through Celite and the filtrate is concentrated in vacuo to afford 5.00 g (98%) of chromane as light yellow oil: 1H NMR (400 MHz, CDCl3) δ 7.15-7.05, 6.89, 6.80, 4.23, 2.84, 2.08-2.02.

Workup

  1. filtrationThe mixture is filtered through Celite
  2. concentrationthe filtrate is concentrated in vacuo

Sources & evidence

ORD record
ord-0fa1abf1326c4d04b407fdc2b4428d03
Source dataset
uspto-grants-2005_10
Patent number
US06951868B2

Reaction notes

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