Chloroform → 2-Methoxy-7,8-dichloro-5,6,7,8-tetrahydronaphthalene-1,4-dione

HRID 726205

Reaction equation

HRID 726205 reaction equation
[CH3:1][O:2][C:3]1[C:4](=[O:14])[C:5]2C[CH:7]=[CH:8][CH2:9][C:10]=2[C:11](=[O:13])[CH:12]=1.[Cl:15]Cl.CCOC(C)=O.COC1C(=O)C2C(C(=O)C=1)=CC=CC=2.[CH:37]([Cl:40])(Cl)Cl>CCO>[CH3:1][O:2][C:3]1[C:4](=[O:14])[C:5]2[CH:37]([Cl:40])[CH:7]([Cl:15])[CH2:8][CH2:9][C:10]=2[C:11](=[O:13])[CH:12]=1

Participants

7

Reactant 5

HCID 6212ChloroformHCID 8857Ethyl AcetateHCID 168712-Methoxy-1,4-NaphthoquinoneHCID 24526ChlorineHCID 197105762-Methoxy-5,8-dihydronaphthalene-1,4-dione

Product 1

HCID 197105382-Methoxy-7,8-dichloro-5,6,7,8-tetrahydronaphthalene-1,4-dione

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent3×

Procedure

To a solution of 2-methoxy-5,8-dihydronaphthalene-1,4-dione (2.75 g, 14.4 mmol) in CHCl3 (60 mL, pre-treated with silica gel to remove the EtOH stabilizer) there was added a solution of Cl2 (~1.10 g, ~15.1 mmol) in EtOH-free CHCl3 (50 mL) in portions over 30 min. TLC (5% EtOAc/95% EtOH) indicated total consumption of the starting material and the appearance of a major higher Rf product spot (lower Rf impurity spots were also noted). The solvent was removed in vacuo to yield a yellow syrup. The addition of 95% EtOH (10 mL) followed by evaporation in vacuo (performed twice) yielded a yellow solid. Crystallization from 95% EtOH (dissolved in 20 mL, allowed to cool to rt) yielded a yellow solid (2.28 g, 60%, ~90% pure by TLC and 1H NMR, mp 119°-123° C.). Recrystallization from 95% EtOH (dissolved in 12 mL, allowed to cool to rt) yielded a yellow crystalline solid (1.89 g, 83% recovery, 50% total yield, ~95% pure by TLC and 1H NMR with the major impurity being 2-methoxynaphthalene-1,4-dione); mp 123°-128° C. (EtOH); 1H NMR (CDCl3) δ3.11 (m, 4H), 3.83 (s, 3H), 4.67 (m, 2H), 5.94 (s, 1H).

Workup

  1. customto remove the EtOH stabilizer) there
  2. customconsumption of the starting material
  3. customThe solvent was removed in vacuo
  4. customto yield a yellow syrup
  5. customfollowed by evaporation in vacuo (
  6. customyielded a yellow solid
  7. customCrystallization from 95% EtOH (dissolved in 20 mL, allowed to cool to rt)
  8. customyielded a yellow solid (2.28 g, 60%, ~90% pure by TLC and 1H NMR, mp 119°-123° C.)
  9. customRecrystallization from 95% EtOH (dissolved in 12 mL, allowed to cool to rt)
  10. customyielded a yellow crystalline solid (1.89 g, 83% recovery, 50% total yield, ~95% pure by TLC and 1H NMR with the major impurity

Sources & evidence

ORD record
ord-4179eb5938264de893d1c9c39a8d878b
Source dataset
uspto-grants-1998_01
Patent number
US05708168

Linked notes

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