Dimethylformamide → 3,4-Dimethylthiophene-2-carbaldehyde

HRID 1444992Notes

Reaction equation

HRID 1444992 reaction equation
[CH3:1][C:2]1[C:6]([CH3:7])=[CH:5][S:4][CH:3]=1.CN([CH:11]=[O:12])C.O=P(Cl)(Cl)Cl.[OH-].[Na+]>CN(C=O)C.C(Cl)(Cl)Cl>[CH:11]([C:3]1[S:4][CH:5]=[C:6]([CH3:7])[C:2]=1[CH3:1])=[O:12]

Participants

6

Reactant 4

HCID 6228Dimethylformamide2×HCID 14798Sodium HydroxideHCID 24813Phosphorus oxychloride2×HCID 790893,4-Dimethylthiophene

Product 1

HCID 125183953,4-Dimethylthiophene-2-carbaldehydeYield 55%

Reagents, catalysts & solvents 1

HCID 21754633chloroform N,N-dimethylformamideSolvent

Procedure

To a solution of 3,4-dimethylthiophene trimer (3.7 g, 11 mmol) in 20 mL of a DMF: CHCl3 (1:1, v:v) solvent mixture, was added 20 mL of a solution of DMF and POCl3 (4:1, v:v). The DMF:POCl3 mixture was added cautiously, dropwise at 0° C. Following the addition, the reaction mixture was allowed to warm to ambient temperature and was stirred overnight. The reaction mixture was then poured into ice water and neutralized with 25% NaOH solution to pH˜8. The aqueous mixture was extracted with dichloromethane. Upon solvent removal the residue was subjected to purification by column chromatography using silica gel and a dichloromethane-petroleum ether (1:3) mixed solvent as the eluting solution to yield pure product 2-formyl-3,4-dimethylthiophen trimer 2.2 g (Yield: 55%) 1H NMR (CDCl3) δ 10.09 (1H, s, CHO), 7.00 (1H, s, aromatic H), 2.54 (3H, s, CH3), 2.23 (3H, s, CH3), 2.16 (3H, s, CH3), 2.13 (3H, s, CH3), 2.11 (6H, s, CH3), and the corresponding trimer dialdehyde 1.57 g (Yield: 37%) 1H NMR (CDCl3) δ 10.09 (2H, s, CHO), 2.54 (6H, s, CH3), 2.15 (12H, m, CH3).

Workup

  1. additionthe addition
  2. extractionThe aqueous mixture was extracted with dichloromethane
  3. customUpon solvent removal the residue
  4. customwas subjected to purification by column chromatography
  5. additiona dichloromethane-petroleum ether (1:3) mixed solvent as the eluting solution

Sources & evidence

ORD record
ord-2b0c049633fe4a69b21f862d1c1c9e1a
Source dataset
uspto-grants-2010_02
Patent number
US07663301B2

Reaction notes

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