5-benzyloxy-2-(6-cyano-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-yl)pyridine N-oxide → 2-(6-cyano-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-yl)-5-hydroxypyridine N-oxide

HRID 892578Notes

Reaction equation

HRID 892578 reaction equation
C([O:8][C:9]1[CH:10]=[CH:11][C:12]([CH:16]2[C:21]3[CH:22]=[C:23]([C:26]#[N:27])[CH:24]=[CH:25][C:20]=3[O:19][C:18]([CH3:29])([CH3:28])[CH2:17]2)=[N+:13]([O-:15])[CH:14]=1)C1C=CC=CC=1>CO.[Pd]>[C:26]([C:23]1[CH:24]=[CH:25][C:20]2[O:19][C:18]([CH3:29])([CH3:28])[CH2:17][CH:16]([C:12]3[CH:11]=[CH:10][C:9]([OH:8])=[CH:14][N+:13]=3[O-:15])[C:21]=2[CH:22]=1)#[N:27]

Participants

4

Reactant 1

HCID 538667995-benzyloxy-2-(6-cyano-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-yl)pyridine N-oxide

Product 1

HCID 540062792-(6-cyano-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-yl)-5-hydroxypyridine N-oxideYield 31.1%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 887MethanolSolvent

Procedure

0.21 g of 5-benzyloxy-2-(6-cyano-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-yl)pyridine N-oxide in 90 ml of methanol was hydrogenated over 10% palladium-on-carbon at room temperature and under atmospheric pressure for 30 minutes. The catalyst was removed by filtration and the filtrate was evaporated. The residue was chromatographed on silica gel using dichloromethane/methanol (19:1) for the elution to give 0.05 g of 2-(6-cyano-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-yl)-5-hydroxypyridine N-oxide in the form of an off-white solid of melting point 224° C (from ethyl acetate).

Workup

  1. customThe catalyst was removed by filtration
  2. customthe filtrate was evaporated
  3. customThe residue was chromatographed on silica gel
  4. washfor the elution

Sources & evidence

ORD record
ord-c1f4e5455bb042079414747f21d49b07
Source dataset
uspto-grants-1992_06
Patent number
US05118694

Reaction notes

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