Réaction #7068

Équation de réaction

4,4,4-trifluoro-3-methoxy-but-2-enoic acid ethyl ester

methyl thioglycolate

H2SO4

KOH

→

title compound

Rendement 91.2%

3-Hydroxy-5-trifluoromethyl-thiophene-2-carboxylic acid methyl ester

Rendement 91.2%

Solvants

MeOH

H2O

MeOH

Conditions de réaction

Traitement

1. 1
   ExtractionThe mixture is extracted with EtOAc (2×250 mL)
2. 2
   LavageThe combined extracts are washed with saturated NaHCO3
3. 3
   ExtractionThe washings are back-extracted with EtOAc
4. 4
   LavageThe combined organic layers are washed with brine
5. 5
   Séchagedried (Na2SO4)
6. 6
   Filtrationfiltered
7. 7
   Concentrationconcentrated

Mode opératoire

A solution of 4,4,4-trifluoro-3-methoxy-but-2-enoic acid ethyl ester (9.6 g, 48.5 mmol) and methyl thioglycolate (4.3 mL, 48.5 mmol) in MeOH (75 mL) is cooled to 5° C. A solution of KOH (3.3 g, 58.2 mmol) in MeOH (75 mL) is then added over 30 min. The reaction mixture is stirred overnight at room temperature. The reaction mixture is then poured over a stirred mixture of ice (75 g), H2O (75 mL) and concentrated H2SO4 (4.5 mL). The mixture is extracted with EtOAc (2×250 mL). The combined extracts are washed with saturated NaHCO3. The washings are back-extracted with EtOAc. The combined organic layers are washed with brine, then dried (Na2SO4), filtered and concentrated to afford the title compound (10 g, 91%) as a brown oil which is used without further purification.

Source