Dimethylformamide → Methyl 5-(2-dimethylaminovinyl)-4-nitrothiophene-2-carboxylate

HRID 1363320Notes

Reaction equation

HRID 1363320 reaction equation
[CH3:1][C:2]1[S:6][C:5]([C:7]([OH:9])=[O:8])=[CH:4][C:3]=1[N+:10]([O-:12])=[O:11].[CH3:13][N:14]([CH:16]=O)[CH3:15].[CH3:18]OC(OC)N(C)C>N1CCCC1>[CH3:13][N:14]([CH3:16])[CH:15]=[CH:1][C:2]1[S:6][C:5]([C:7]([O:9][CH3:18])=[O:8])=[CH:4][C:3]=1[N+:10]([O-:12])=[O:11]

Participants

5

Reactant 3

HCID 6228DimethylformamideHCID 78373Dimethylformamide dimethyl acetalHCID 31107845-Methyl-4-nitrothiophene-2-carboxylic acid

Product 1

HCID 72053195Methyl 5-(2-dimethylaminovinyl)-4-nitrothiophene-2-carboxylateYield 26.9%

Reagents, catalysts & solvents 1

HCID 31268PyrrolidineCatalyst

Procedure

To a solution of 5-methyl-4-nitro-2-thiophene carboxylic acid (4.6 g, 24.6 mmol) in DMF (14.5 mmol) was added N,N-dimethylformamide dimethyl acetal (3.8 mL, 28.5 mmol) and pyrrolidine (2 drops). The mixture was refluxed for 3 h, concentrated in vacuo and the residue taken up in EtOAc (0.2 L). The organic phase was washed with water, saturated aq NaCl, dried over Na2SO4, filtered and concentrated in vacuo. The crude product was chromatographed over silica gel (0 to 40% EtOAc/heptane over 60 min) to give methyl 5-(2-dimethylaminovinyl)-4-nitrothiophene-2-carboxylate as a dark red solid (1.0 g, 16%). 1H NMR (400 MHz, CDCl3) δ (ppm) 8.10 (s, 1H) 7.31 (d, J=13.1 Hz, 1H) 6.56 (d, J=13.1 Hz, 1H) 3.87 (s, 3H) 3.07 (s, 6H). LCMS m/e 279 (M+Na).

Workup

  1. temperatureThe mixture was refluxed for 3 h
  2. concentrationconcentrated in vacuo
  3. washThe organic phase was washed with water, saturated aq NaCl
  4. dry with materialdried over Na2SO4
  5. filtrationfiltered
  6. concentrationconcentrated in vacuo
  7. customThe crude product was chromatographed over silica gel (0 to 40% EtOAc/heptane over 60 min)

Sources & evidence

ORD record
ord-3bb9152e7c1247e2ad445b8ab933419c
Source dataset
uspto-grants-2011_02
Patent number
US07884124B2

Reaction notes

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