6,8-di-t-butyl-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester → 6,8-di-t-butyl-2,3-dihydro-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester

HRID 973269Notes

Reaction equation

HRID 973269 reaction equation
[C:1]([C:5]1[CH:6]=[C:7]([C:21]([CH3:24])([CH3:23])[CH3:22])[C:8]2[O:13][C:12]([C:14]([O:16][CH2:17][CH3:18])=[O:15])=[CH:11][C:10](=[O:19])[C:9]=2[CH:20]=1)([CH3:4])([CH3:3])[CH3:2].[H][H]>[Ni]>[C:1]([C:5]1[CH:6]=[C:7]([C:21]([CH3:22])([CH3:24])[CH3:23])[C:8]2[O:13][CH:12]([C:14]([O:16][CH2:17][CH3:18])=[O:15])[CH2:11][C:10](=[O:19])[C:9]=2[CH:20]=1)([CH3:4])([CH3:3])[CH3:2]

Participants

4

Reactant 2

HCID 538439426,8-di-t-butyl-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl esterHCID 178418361HCID 178418361, compound

Product 1

HCID 867332766,8-di-t-butyl-2,3-dihydro-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester

Reagents, catalysts & solvents 1

HCID 935NickelCatalyst

Procedure

A solution of 12.0 parts of 6,8-di-t-butyl-4-oxo-4H-1benzopyran-2-carboxylic acid, ethyl ester in 150 parts of ethanoo was hydrogenated, using Raney Nickel as catalyst, until one equivalent of hydrogen had been absorbed. The catalyst was removed by filtration and the ethanol was evaporated to give a residue which was chromatographed on silica gel. Careful elution with a 1:1 mixture of chloroform and light petroleum (b.p. 60°-80° C) gave 3.73 parts of 6,8-di-t-butyl-2,3-dihydro-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester, m.p. 61°-63° C, as a yellow solid.

Workup

  1. customThe catalyst was removed by filtration
  2. customthe ethanol was evaporated
  3. customto give a residue which
  4. customwas chromatographed on silica gel
  5. washCareful elution
  6. additionwith a 1:1 mixture of chloroform and light petroleum (b.p. 60°-80° C)

Sources & evidence

ORD record
ord-ab2e1a7a5fa143f68288138043bd2441
Source dataset
uspto-grants-1977_10
Patent number
US04055654

Reaction notes

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