Sulfuric Acid → 9-methoxy-4-propyl-1,2,3,4a,5,10b-hexahydro-4H-[1]-benzopyrano[3,4-b]pyridine

HRID 364130Notes

Reaction equation

HRID 364130 reaction equation
[H-].[Al+3].[Li+].[H-].[H-].[H-].S(=O)(=O)(O)O.[CH3:12][O:13][C:14]1[CH:15]=[CH:16][C:17]2[O:31][CH2:30][CH:21]3[N:22]([C:26](=O)[CH2:27][CH3:28])[CH2:23][CH2:24][CH2:25][CH:20]3[C:18]=2[CH:19]=1>O1CCCC1>[CH3:12][O:13][C:14]1[CH:15]=[CH:16][C:17]2[O:31][CH2:30][CH:21]3[N:22]([CH2:26][CH2:27][CH3:28])[CH2:23][CH2:24][CH2:25][CH:20]3[C:18]=2[CH:19]=1

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 20153968HCID 20153968, compoundHCID 21226445Aluminium lithium hydride

Product 1

HCID 141515789-methoxy-4-propyl-1,2,3,4a,5,10b-hexahydro-4H-[1]-benzopyrano[3,4-b]pyridine

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a suspension of 3.8 g of lithium aluminium hydride in 100 ml of tetrahydrofuran, 3.6 g of concentrated sulfuric acid is added dropwise at -5° to -10°, then 5.0 g of 9-methoxy-4-propionyl-1,2,3,4a,5,10b-hexahydro-4H-[1]-benzopyrano[3,4-b]pyridine is added slowly with stirring. The reaction mixture is allowed to warm to room temperature, stirred for 18 hours and finally heated under reflux for 1 hour. After cooling the reaction mixture is quenched with ethyl acetate, then treated with a small volume of water and 3N sodium hydroxide, filtered and concentrated in vacuo. The residue is redissolved in ethyl acetate and the ethyl acetate solution is washed with water, dried and evaporated to yield 9-methoxy-4-propyl-1,2,3,4a,5,10b-hexahydro-4H-[1]-benzopyrano[3,4-b]pyridine. The starting material is prepared by treatment of 9-methoxy-1,2,3,4a,5,10b-hexahydro-4H-[1]-benzopyrano[3,4-b]pyridine in the presence of two mole equivalents of powdered potassium carbonate in methylene chloride solution with 1 mole of propionyl chloride at room temperature overnight.

Workup

  1. additionis added dropwise at -5° to -10°
  2. stirringstirred for 18 hours
  3. temperaturefinally heated
  4. temperatureunder reflux for 1 hour
  5. temperatureAfter cooling the reaction mixture
  6. customis quenched with ethyl acetate
  7. additiontreated with a small volume of water and 3N sodium hydroxide
  8. filtrationfiltered
  9. concentrationconcentrated in vacuo
  10. dissolutionThe residue is redissolved in ethyl acetate
  11. washthe ethyl acetate solution is washed with water
  12. customdried
  13. customevaporated

Sources & evidence

ORD record
ord-2d6357ff5de747a89f481782821b7fe5
Source dataset
uspto-grants-1986_08
Patent number
US04604397

Reaction notes

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