Phthalic Anhydride → 6,7-Methylenedioxy-3-nitrochromene

HRID 1881719Notes

Reaction equation

HRID 1881719 reaction equation
[OH:1][C:2]1[C:3]([CH:11]=O)=[CH:4][C:5]2[O:9][CH2:8][O:7][C:6]=2[CH:10]=1.C(NCCCC)CCC.C1(=O)OC(=O)C2=CC=CC=C12.[N+:33]([CH:36](O)[CH3:37])([O-:35])=[O:34]>C(Cl)Cl>[CH2:8]1[O:7][C:6]2[CH:10]=[C:2]3[C:3]([CH:11]=[C:36]([N+:33]([O-:35])=[O:34])[CH2:37][O:1]3)=[CH:4][C:5]=2[O:9]1

Participants

6

Reactant 4

HCID 6811Phthalic AnhydrideHCID 8148DibutylamineHCID 67106266-Hydroxy-1,3-dioxaindane-5-carbaldehydeHCID 22056827Nitroethanol

Product 1

HCID 575569416,7-Methylenedioxy-3-nitrochromeneYield 61.2%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

Aldehyde (2a) (6 g, 36.14 mmol) was dissolved in 300 ml of CH2Cl2 along with 3.1 ml of dibutylamine (18.16 mmol) and 10.72 g of phthalic anhydride in a two necked flask equipped with a Dean-Stark trap, a condenser and a dropping funnel. Nitroethanol (7 ml 97.69 mmol) was added dropwise over a period of 18 hours, while the solution was stirred at reflux. After addition, the reaction was stirred for an additional 24 hrs. The flask was then cooled to room temperature, filtered and the solution extracted with 2 M NaOH (300 ml×3) and brine (100 ml), then dried over MgSO4. The solvent was then evaporated to leave a concentrated solution which was passed through a short column of silica to remove dark polar impurities. The isolated material was recrystallized from methanol to give 4.89 g (61% yield) of the title compounds as red needles: mp 139° C.; 1H-NMR (CDCl3) δ 5.20 (s, 2, ArOCH2), 6.02 (s, 2, OCH2O), 6.49 (s, 1, ArH), 6.69 (s, 1, ArH), 7.75 (s, 1, ArCH).

Workup

  1. customequipped with a Dean-Stark trap, a condenser and a dropping funnel
  2. temperatureat reflux
  3. additionAfter addition
  4. stirringthe reaction was stirred for an additional 24 hrs
  5. filtrationfiltered
  6. extractionthe solution extracted with 2 M NaOH (300 ml×3) and brine (100 ml)
  7. dry with materialdried over MgSO4
  8. customThe solvent was then evaporated
  9. customto leave a concentrated solution which
  10. customto remove dark polar impurities
  11. customThe isolated material was recrystallized from methanol

Sources & evidence

ORD record
ord-de803bfe9ed44e0bb3284dd90dbc69b0
Source dataset
uspto-grants-2012_11
Patent number
US08318938B2

Reaction notes

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