Réaction #157256

Équation de réaction

bromine

sodium bicarbonate

o-cresol

sodium thiocyanate

sodium bromide

→

3-methyl-4-hydroxy-phenyl thiocyanic acid

Rendement 69.8%

Solvants

methanol

methanol

Conditions de réaction

Traitement

1. 1
   Températurethe mixture was warmed up to room temperature
2. 2
   workup.STIRRINGstirred for another 4 hours at room temperature
3. 3
   workup.STIRRINGstirred for 10 min
4. 4
   ExtractionThe mixture was extracted with ethyl acetate (2×500 ml)
5. 5
   SéchageThe combined organic layer was dried over anhydrous magnesium sulfate
6. 6
   Filtrationfiltrated
7. 7
   Concentrationconcentrated under reduced pressure
8. 8
   Autreto give yellow oil
9. 9
   AutreSilica gel column chromatography purification (silica-gel H: 300-400 mesh; petroleum ether/ethyl acetate=8:1 v/v)

Mode opératoire

To a 500 ml three-necked flask were added sequentially with agitation o-cresol (15 g, 138.7 mmol), sodium thiocyanate (NaSCN, 34 g, 419.3 mmol), sodium bromide (NaBr, 16 g, 155.5 mmol) and methanol (200 ml). The mixture was cooled to 0° C., and then a solution of bromine (8.6 ml, 167 mmol) in methanol (30 ml) was added dropwise thereinto. After 1 hour of stirring at 0° C., the mixture was warmed up to room temperature and then stirred for another 4 hours at room temperature. After the reaction was completed, a 200 ml saturated aqueous solution of sodium bicarbonate (NaHCO3) was added to the reaction mixture and stirred for 10 min. The mixture was extracted with ethyl acetate (2×500 ml). The combined organic layer was dried over anhydrous magnesium sulfate, filtrated, concentrated under reduced pressure to give yellow oil. Silica gel column chromatography purification (silica-gel H: 300-400 mesh; petroleum ether/ethyl acetate=8:1 v/v) was performed to yield 3-methyl-4-hydroxy-phenyl thiocyanic acid as a white solid (16 g, yield: 69.8%).

Source