Acetic Acid → Diethyl 1H-pyrrole-2,4-dicarboxylate

HRID 1796641Notes

Reaction equation

HRID 1796641 reaction equation
[N+:1]([CH2:3][C:4]([O:6][CH2:7][CH3:8])=[O:5])#[C-:2].[CH2:9]1[CH2:19][CH2:18]N2C(=NCCC2)CC1.C=[O:21].[CH3:22][C:23](O)=[O:24]>C1COCC1>[C:4]([C:3]1[NH:1][CH:2]=[C:19]([C:18]([O:24][CH2:23][CH3:22])=[O:21])[CH:9]=1)([O:6][CH2:7][CH3:8])=[O:5]

Participants

6

Reactant 4

HCID 176Acetic AcidHCID 712FormaldehydeHCID 811841,8-Diazabicyclo(5.4.0)undec-7-eneHCID 533707Ethyl isocyanoacetate

Product 1

HCID 12711558Diethyl 1H-pyrrole-2,4-dicarboxylateYield 38%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a stirred solution of ethyl isocyanoacetate (0.02 mol, 2.3 mL) and DBU (3.0 g, 0.02 mol) in THF (30 mL) was added a solution of formaldehyde (0.6M THF solution, 16.6 mL, 0.01 mole) at 45-50° C. for a period of 15 min. After stirring for 5 hr at the same temperature, the reaction mixture was neutralized with HOAc and the solvents were removed under reduced pressure. The resulting oil was partitioned between satd. aq. NaHCO3 and EtOAc. The EtOAc layer was separated, dried with Na2SO4 and concentrated in vacuo to obtain a viscous oil which was chromatographed on silica (20% EtOAc—hexanes) to give 403A (0.80 g, 38%). MS Found: (M+H)+=212.0;

Workup

  1. customthe solvents were removed under reduced pressure
  2. customThe resulting oil was partitioned between satd
  3. customThe EtOAc layer was separated
  4. dry with materialdried with Na2SO4
  5. concentrationconcentrated in vacuo
  6. customto obtain a viscous oil which
  7. customwas chromatographed on silica (20% EtOAc—hexanes)

Sources & evidence

ORD record
ord-c762aa939e5c48fbb36427b48bccca8c
Source dataset
uspto-grants-2006_04
Patent number
US07030112B2

Reaction notes

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