Dimethylformamide → Benzaldehyde, 4-(diphenylamino)-

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Reaction Conditions

Reaction Steps

4-(Diphenylamino)benzaldehyde can be obtained commercially from a supplier, such as Aldrich, Milwauke, Wis. or Fluka, Buchs SG, Switzerland. It could also be prepared by the following procedure. Dry dimethylformamide (DMF, 4.73 ml, 0.0612 mol) was added to a 25 ml 3-neck round bottom flask equipped with a reflux condenser and a mechanical stirrer. After the flask was kept under nitrogen atmosphere and cooled to 0° C., phosphorus oxychloride (POCl3, 3.8 ml, 0.0408 mol) was added dropwise. The temperature inside the flask was kept below 5° C. during the addition of POCl3. After the addition of POCl3 was completed, the solution was allowed to warm up slowly to room temperature. Then a solution of triphenylamine (5 g, 0.0204 mol, from Aldrich, Milwauke, Wis.) in dry DMF (10 ml) was added dropwise. The reaction mixture was refluxed at 80° C. for 24 hours and then poured into ice water. This solution was neutralized with potassium hydroxide until the pH reached between 6 and 8. The product was extracted with chloroform. The chloroform extract was dried with anhydrous sodium sulfate, filtered, and evaporated off to form the crude product, which was recrystallized from methanol to yield 5.57 g (72%) of 4-(diphenylamino)benzaldehyde. The melting point was found to be 126.5° C. The 1H-NMR spectrum (100 MHz) of the product in CDCl3 was characterized by the following chemical shifts (δ, ppm): 6.57–7.56 (m, 12H, Ar), 7.60–7.98 (m, 2H, Ar), 10.21 (s, 1H, CHO). The IR spectrum of the product was characterized by the following absorption frequencies (KBr, cm−1): ν(C—H) 2743; 2830, ν(C—H in Ar) 3037, ν(C═O) 1689, ν(C═C in Ar) 1585; 1567; 1490, γ(Ar) 825. The mass spectrum of the product was characterized by the following mass peaks (m/z): 274 (100%, M+1).

Provenance & Evidence