Reaction #6674

Reaction equation

potassium hydroxide

Phosphorus oxychloride

dimethylformamide

10-ethylphenothiazine

DMF

→

10-Ethylphenothiazine-3-carbaldehyde

Conditions

Workup

1. 1
   TemperatureThe reaction mixture was refluxed at 80° C. for 24 hours
2. 2
   ExtractionThe product was extracted with chloroform
3. 3
   ExtractionThe chloroform extract
4. 4
   Dryingwas dried with anhydrous sodium sulfate
5. 5
   Filtrationfiltered
6. 6
   workup.DISTILLATIONdistilled
7. 7
   OtherThe product was crystallized from methanol

Procedure

Phosphorus oxychloride (POCl3,3.7 ml, 0.04 mol) 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, a solution of 5 g (0.02 mol) of 10-ethylphenothiazine in dry DMF was added dropwise. The reaction mixture was refluxed at 80° C. for 24 hours and poured into the ice water. This 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 crystallized from methanol. The yield of 10-ethylphenothiazine-3-carbaldehyde (C15H13NOS, FW=255.34) was 65%.

Source