Potassium Carbonate → 4-ethyl-8-methoxy-1H-pyrano[3,4-c]pyridine

HRID 357506Notes

Reaction equation

HRID 357506 reaction equation
[CH2:1]([O:5][CH2:6][C:7]1[C:8]([O:14][CH3:15])=[N:9][CH:10]=[CH:11][C:12]=1I)[CH:2]=[CH:3][CH3:4].C(=O)([O-])[O-].[K+].[K+]>[Cl-].C([N+](CCCC)(CCCC)CCCC)CCC.CN(C)C=O.C([O-])(=O)C.[Pd+2].C([O-])(=O)C.[Rh]Cl.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>[CH2:3]([C:2]1[C:12]2[C:7](=[C:8]([O:14][CH3:15])[N:9]=[CH:10][CH:11]=2)[CH2:6][O:5][CH:1]=1)[CH3:4]

Participants

7

Reactant 2

HCID 11430Potassium CarbonateHCID 544155093-(But-2-enyloxymethyl)-4-iodo-2-methoxypyridine

Product 1

HCID 106315694-ethyl-8-methoxy-1H-pyrano[3,4-c]pyridine

Reagents, catalysts & solvents 4

HCID 70681Tetrabutylammonium ChlorideCatalystHCID 167845palladium(II) acetateCatalystHCID 178479813HCID 178479813, compoundCatalystHCID 6228DimethylformamideSolvent

Conditions

Temperature
90 °C

Procedure

A mixture of 3-(but-2-enyloxymethyl)-4-iodo-2-methoxy-pyridine (228 g, 0.714 mol), potassium carbonate (200 g, 1.45 mol) and tetrabutylammonium chloride (100 g, 0.36 mol) in N,N-dimethylformamide (3.5 L) is purged with nitrogen for 20 min prior to the addition of palladium(II) acetate (3.75 g, 0.0167 mol) and tris(triphenylphosphine) rhodium(I) chloride (5.31 g, 0.00574 mol). The mixture is heated at 90° C. for about 4 h, cooled to below 50° C. and filtered through a pad of Celite®. The pad is washed with tert-butyl methyl ether (200 ml). The filtrate is washed with water (4×3 L), dried over sodium sulfate (260 g) and concentrated to a dark oil that is vacuum distilled (about 85°-98° C., about 6 mm Hg) to provide 4-ethyl-8-methoxy-1H-pyrano[3,4-c]pyridine as a yellow-orange oil which contains a 14.3:1 ratio of 4-ethyl-8-methoxy-1H-pyrano[3,4-c]pyridine to the corresponding double bond isomer, 4-ethylidene-8-methoxy-3,4-dihydro-1H-pyrano[3,4-c]pyridine.

Workup

  1. customis purged with nitrogen for 20 min
  2. temperaturecooled to below 50° C.
  3. filtrationfiltered through a pad of Celite®
  4. washThe pad is washed with tert-butyl methyl ether (200 ml)
  5. washThe filtrate is washed with water (4×3 L)
  6. dry with materialdried over sodium sulfate (260 g)
  7. concentrationconcentrated to a dark oil that
  8. distillationdistilled (about 85°-98° C., about 6 mm Hg)

Sources & evidence

ORD record
ord-d7633b52d1c5453e905c31dfe8d11945
Source dataset
uspto-grants-1998_11
Patent number
US05840898

Reaction notes

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