Dipropylamine → 5-Methoxy-N,N-dipropyl-3,4-dihydro-2H-1-benzopyran-3-amine

HRID 1464696Notes

Reaction equation

HRID 1464696 reaction equation
Br[C:2]1[CH:3]=[CH:4][C:5]([O:13][CH3:14])=[C:6]2[C:11]=1[O:10][CH2:9][C:8](=O)[CH2:7]2.[CH2:15]([NH:18][CH2:19][CH2:20][CH3:21])[CH2:16][CH3:17].O.C1(C)C=CC(S(O)(=O)=O)=CC=1.[OH-].[Na+]>C1C=CC=CC=1.[Pd].C(O)C>[CH2:15]([N:18]([CH2:19][CH2:20][CH3:21])[CH:8]1[CH2:7][C:6]2[C:11](=[CH:2][CH:3]=[CH:4][C:5]=2[O:13][CH3:14])[O:10][CH2:9]1)[CH2:16][CH3:17]

Participants

8

Reactant 4

HCID 8902DipropylamineHCID 14798Sodium HydroxideHCID 521998p-Toluenesulfonic acid monohydrateHCID 147034268-Bromo-5-methoxy-3-chromanone

Product 1

HCID 30825975-Methoxy-N,N-dipropyl-3,4-dihydro-2H-1-benzopyran-3-amineYield 77%

Reagents, catalysts & solvents 3

HCID 23938PalladiumCatalystHCID 241BenzeneSolventHCID 702EthanolSolvent

Procedure

To a solution of 8-bromo-5-methoxy-3-chromanone (125 mg, 0.49 mmol) in benzene (20 ml) was added di-n-propylamine (0.5 ml, 3.7 mmol) and p-toluenesulfonic acid monohydrate (10 mg, 0.08 mmol). The solution was refluxed for 5 hours with a Dean-Stark apparatus under N2 -atmosphere. The reaction mixture was poured into a Parr-flask, absolute ethanol was added (50 ml) and pH was adjusted to 11 with 2M-NaOH-solution. The product was hydrogenated overnight with Pd/C as catalyst. The catalysst was filtered off and the solvent was evaporated. The residual oil was dissolved in CH2Cl2 and washed with 5% aqueous Na2CO3. The phases were separated and the organic layer was dried (Na2CO3) yielding 99 mg (77%) of the product as an oil with physical data identical with authentic material synthesized by alternative methods.

Workup

  1. temperatureThe solution was refluxed for 5 hours with a Dean-Stark apparatus under N2 -atmosphere
  2. additionThe reaction mixture was poured into a Parr-flask
  3. filtrationThe catalysst was filtered off
  4. customthe solvent was evaporated
  5. dissolutionThe residual oil was dissolved in CH2Cl2
  6. washwashed with 5% aqueous Na2CO3
  7. customThe phases were separated
  8. dry with materialthe organic layer was dried (Na2CO3)

Sources & evidence

ORD record
ord-3bfa44a0455e480eadc687f7e81f9914
Source dataset
uspto-grants-1994_04
Patent number
US05306830

Reaction notes

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