Réaction #1164

Équation de réaction

4,4,5,8-tetramethylthiochroman-6-carboxylic acid-1,1-dioxide

DCC

1-ethyl-5-hydroxypyrazole

5-hydroxypyrazole

potassium carbonate

thiochroman carboxylic acid

→

4,4,5,8-tetramethyl-6-(1-ethyl-5-hydroxypyrazol-4-yl)carbonylthiochroman-1,1-dioxide

Rendement 62.6%

Solvants

tert-amyl alcohol

Conditions de réaction

Traitement

1. 1
   Autreto react at 80° C. for 8 hours
2. 2
   workup.DISTILLATIONthe reaction solvent was distilled off under reduced pressure
3. 3
   workup.ADDITIONThe resultant residue was dispersed in a 5% potassium carbonate aqueous solution and ethyl acetate
4. 4
   Autreto separate it into two layers
5. 5
   Filtrationthe formed solid was recovered by filtration

Mode opératoire

7.4 Grams (0.026 mol) of 4,4,5,8-tetramethylthiochroman-6-carboxylic acid-1,1-dioxide corresponding to thiochroman carboxylic acid (IIIc), 3.4 g (0.03 mol) of 1-ethyl-5-hydroxypyrazole corresponding to 5-hydroxypyrazole (II) and 6.22 g (0.03 mol) of DCC (N,N'-dicyclohexylcarbodiimide) were all together added to 50 ml of tert-amyl alcohol, and the mixture was stirred at room temperature for 30 minutes. Then, 1.8 g (0.013 mol) of anhydrous potassium carbonate was added. The reaction mixture was allowed to react at 80° C. for 8 hours, and the reaction solvent was distilled off under reduced pressure. The resultant residue was dispersed in a 5% potassium carbonate aqueous solution and ethyl acetate to separate it into two layers. Further, the aqueous layer was adjusted to a pH of 1 with 5% hydrochloric acid, and the formed solid was recovered by filtration to give 6.13 g (yield 62%) of 4,4,5,8-tetramethyl-6-(1-ethyl-5-hydroxypyrazol-4-yl)carbonylthiochroman-1,1-dioxide (Compound Ic-1).

Source