Réaction #64050

Équation de réaction

4-chloro-3,5-dimethylphenol

dichloromethylmethyl ether

→

3-chloro-6-hydroxy-2,4-dimethylbenzaldehyde

Solvants

dichloromethane

dichloromethane

Conditions de réaction

Traitement

1. 1
   Autrebeing kept below 10° C.
2. 2
   workup.WAITto remian at 20° C. for 30 minutes
3. 3
   TempératureFinally the solution was warmed at 35° C. for 15 minutes
4. 4
   Autrewas separated
5. 5
   Extractionthe aqueous phase was extracted with more dichloromethane (2×50 ml)
6. 6
   LavageThe combined organic layers were washed with water thoroughly (4×200 ml)
7. 7
   Séchagedried over anhydrous magnesium sulphate
8. 8
   AutreThe drying agent was removed by filtration
9. 9
   Concentrationthe filtrate was concentrated under reduced pressure
10. 10
    Autrea rotary evaporator

Mode opératoire

A solution of 4-chloro-3,5-dimethylphenol (16 g, 0.1 mole) in dichloromethane (100 ml) was stirred and cooled to 2° C. in an ice bath. Titanium tetrachloride (35 g, 0.18 mole) was added dropwise over a period of 10 minutes and dichloromethylmethyl ether (11.5 g, 0.1 mole) was added slowly to the dark red solution, the temperature being kept below 10° C. throughout. After the solution had been stirred at 5° C. for 30 minutes the temperature was allowed to rise and to remian at 20° C. for 30 minutes. Finally the solution was warmed at 35° C. for 15 minutes and then poured into ice water (200 ml). The mixture was shaken vigorously until almost colourless and then the dichloromethane layer was separated and the aqueous phase was extracted with more dichloromethane (2×50 ml). The combined organic layers were washed with water thoroughly (4×200 ml) and then dried over anhydrous magnesium sulphate. The drying agent was removed by filtration and the filtrate was concentrated under reduced pressure using a rotary evaporator. The product, 3-chloro-6-hydroxy-2,4-dimethylbenzaldehyde was isolated as a white solid (13 g, 70%), mp 89°-90° C. Proton magnetic resonance spectrum (CDCl3 ; δ in ppm): 2.40 (3H, s); 2.64 (3H, s); 6.71 (1H, s); 10.23 (1H, s); 11.91 (1H, s).

Source