2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 5-[3-(cyclopentyloxy)-4-methoxyphenyl]-1,2-dihydro-1-methyl-3H-pyrazol-3-one

HRID 1655626Notes

Reaction equation

HRID 1655626 reaction equation
[CH:1]1([O:6][C:7]2[CH:8]=[C:9]([CH:15]3[N:19]([CH3:20])[NH:18][C:17](=[O:21])[CH2:16]3)[CH:10]=[CH:11][C:12]=2[O:13][CH3:14])[CH2:5][CH2:4][CH2:3][CH2:2]1.ClC1C(=O)C(C#N)=C(C#N)C(=O)C=1Cl>O1CCCC1>[CH:1]1([O:6][C:7]2[CH:8]=[C:9]([C:15]3[N:19]([CH3:20])[NH:18][C:17](=[O:21])[CH:16]=3)[CH:10]=[CH:11][C:12]=2[O:13][CH3:14])[CH2:2][CH2:3][CH2:4][CH2:5]1

Participants

4

Reactant 2

HCID 67752,3-Dichloro-5,6-dicyano-1,4-benzoquinoneHCID 197927655-[3-(Cyclopentyloxy)-4-methoxyphenyl]-1-methyl-3-pyrazolidinone

Product 1

HCID 197927825-[3-(cyclopentyloxy)-4-methoxyphenyl]-1,2-dihydro-1-methyl-3H-pyrazol-3-oneYield 32.7%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

To a magnetically-stirred solution of 5-[3-(cyclopentyloxy)-4-methoxyphenyl]-1-methyl-3-pyrazolidinone (68.88 mmol, 20.0 g) in dry tetrahydrofuran (300 mL) at 0° C. is added, via cannula, a suspension of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ, 68.88 mmol, 15.64 g) in 200 mL dry tetrahydrofuran. The resulting heterogeneous mixture is allowed to warm slowly from O° C. to room temperature overnight. The solvent is removed in vacuo and the reddish-brown residue is triturated with methylene chloride. The undissolved yellow solid is removed via suction and discarded. The filtrate is concentrated in vacuo to produce a brownish foam which is purified by flash chromatography (SiO2 : gradient ranging from 15% ethyl acetate/methylene chloride to 30% ethyl acetate/methylene chloride). Concentration in vacuo affords a light tan solid which is dried overnight in vacuo at 50° C. to give the title compound (22.54 mmol, 6.50 g., 32.7%). 1H NMR (DMSO-d6,400 MHz) δ 9.58 (s, 1H); 6.98 (m, 3H); 5.53 (s, 1H); 4.83 (m, 1H); 3.77 (s, 3H); 3.60 (s, 3H); 1.90 (m, 2H); 1.70 (m, 4H); 1.55 (m, 2H). IR (KBr, cm-1) 3440, 2950, 2830, 1950, 1600, 1517, 1483, 1310, 1252, 1235, 1165, 1135, 1020, 770.

Workup

  1. temperatureto warm slowly from O° C
  2. customto room temperature
  3. customovernight
  4. customThe solvent is removed in vacuo
  5. customthe reddish-brown residue is triturated with methylene chloride
  6. customThe undissolved yellow solid is removed via suction
  7. concentrationThe filtrate is concentrated in vacuo
  8. customto produce a brownish foam which
  9. customis purified by flash chromatography (SiO2 : gradient ranging from 15% ethyl acetate/methylene chloride to 30% ethyl acetate/methylene chloride)
  10. concentrationConcentration in vacuo
  11. customaffords a light tan solid which
  12. customis dried overnight in vacuo at 50° C.

Sources & evidence

ORD record
ord-e5749d661f894714aef6a305b82ae429
Source dataset
uspto-grants-1993_10
Patent number
US05250700

Reaction notes

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