Dimethylformamide → 10-Ethylphenothiazine-3-carbaldehyde

Participants

Reaction Steps

A 3.7 ml (0.04 mol) quantity of phosphorus oxychloride (from Aldrich) was added dropwise to 4.4 ml (0.06 mol) of dry dimethylformamide (DMF) at 0° C. under a nitrogen atmosphere. This solution was warmed up slowly to room temperature. Then 5 g (0.02 mol) of 10-ethylphenothiazine in dry DMF was added dropwise to the solution. The reaction mixture was heated at 80° C. for 24 hours and poured into ice water. The obtained solution was neutralized with potassium hydroxide until the pH reached 6–8. The product was extracted with chloroform. The chloroform extract was dried with anhydrous sodium sulfate, filtered and distilled. The product was recrystallized from methanol. The yield of 10-ethylphenothiazine-3-carbaldehyde was 3.7 g (66%). The product had a melting point of 94–95° C. (recrystallized from methanol). A 1H NMR spectrum yielded the following results: (100 MHz, CDCl3, δ, ppm): 1.50 (t, J=7.0 Hz, 3H, CH3); 4.02 (q, J=7.0 Hz, 2H, CH2); 6.95–6.39 (m, 5H, Ar), 7.52–7.70 (m, 2H, Ar), 9.83 (s, 1H, CHO).

Provenance & Evidence