Potassium Carbonate → 1-(3,4-Dihydro-2H-1-benzopyran-6-yl)piperazine

HRID 1018936Notes

Reaction equation

HRID 1018936 reaction equation
[NH2:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[O:8][CH2:7][CH2:6][CH2:5]2.Cl.Cl[CH2:14][CH2:15][NH:16][CH2:17][CH2:18]Cl.C(=O)([O-])[O-].[K+].[K+]>ClC1C=CC=CC=1>[O:8]1[C:9]2[C:4](=[CH:3][C:2]([N:1]3[CH2:18][CH2:17][NH:16][CH2:15][CH2:14]3)=[CH:11][CH:10]=2)[CH2:5][CH2:6][CH2:7]1

Participants

5

Reactant 3

HCID 11430Potassium CarbonateHCID 522769Bis(2-chloroethyl)amine hydrochlorideHCID 132978913,4-Dihydro-2H-1-benzopyran-6-amine

Product 1

HCID 154850101-(3,4-Dihydro-2H-1-benzopyran-6-yl)piperazine

Reagents, catalysts & solvents 1

HCID 7964ChlorobenzeneSolvent

Procedure

A solution of 6-aminochroman from part 2 of this example (0.300 g, 2.013 mmol), bis-(2-choroethyl)amine hydrochloride (0.539 g, 3.020 mmol) and potassium carbonate (0.278 g, 2.013 mmol) in 10 mL chlorobenzene is heated at reflux for 24 h. The dark brown reaction mixture is then partitioned between 3N NaOH and methylene chloride. The organic layer is separated, dried over Mg2SO4, filtered and concentrated. Purification by flash column chromatography (5% methanol-methylene chloride) affords 0.157 g (36%) of 1-(chroman-6-yl)piperazine as a white solid, TLC Rf 0.35 (elution with 10% methanol-methylene chloride).

Workup

  1. temperatureat reflux for 24 h
  2. customThe dark brown reaction mixture is then partitioned between 3N NaOH and methylene chloride
  3. customThe organic layer is separated
  4. dry with materialdried over Mg2SO4
  5. filtrationfiltered
  6. concentrationconcentrated
  7. customPurification by flash column chromatography (5% methanol-methylene chloride)
  8. customaffords
  9. wash0.157 g (36%) of 1-(chroman-6-yl)piperazine as a white solid, TLC Rf 0.35 (elution with 10% methanol-methylene chloride)

Sources & evidence

ORD record
ord-72781df9a31a4fabbd84c58c434cfe1a
Source dataset
uspto-grants-2002_11
Patent number
US06486164B2

Reaction notes

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