Réaction #8175

Équation de réaction

Dimethyloxalate

sodium methoxide

HCl

4′-(methylthio)acetophenone

→

title compound

Rendement 79.0%

Methyl (2Z)-2-hydroxy-4-(4-methylthiophenyl)-4-oxobut-2-enoate

Rendement 79.0%

Solvants

toluene

EtOAc

CH2Cl2

toluene

hexane

Conditions de réaction

Traitement

1. 1
   Autregiving a yellow suspension which
2. 2
   workup.STIRRINGwas stirred for 2 hours at room temperature
3. 3
   AutreThe thick yellow suspension was transferred to a 2 liter flask
4. 4
   workup.DISSOLUTIONto dissolve all the solid present
5. 5
   AutreThe organic layer was separated
6. 6
   Extractionthe aqueous layer was extracted with EtOAc (100 mL)
7. 7
   LavageThe combined organic extracts were washed with water (250 mL)
8. 8
   Séchagedried over Na2SO4
9. 9
   Autrethe solvent was evaporated under reduced pressure
10. 10
    Autreto give thick brown oil

Mode opératoire

Dimethyloxalate (26 g, 180.7 mmol) was added to a stirred suspension of sodium methoxide (9.75 g, 180.7 mmol) in dry toluene (200 mL) at 0° C. The white suspension was stirred for 15 min at 0° C. A solution of 4′-(methylthio)acetophenone (15 g, 90.4 mmol) in dry toluene (150 mL) was then added drop-wise over 15 minutes giving a yellow suspension which was stirred for 2 hours at room temperature. The thick yellow suspension was transferred to a 2 liter flask and stirred vigorously with 10% HCl (250 mL) and EtOAc (200 mL) to dissolve all the solid present. The organic layer was separated and the aqueous layer was extracted with EtOAc (100 mL). The combined organic extracts were washed with water (250 mL), dried over Na2SO4 and the solvent was evaporated under reduced pressure to give thick brown oil. The brown oil was dissolved in CH2Cl2 (25 mL) and hexane (125 mL) and left in a freezer at −20° C. for 16 hours to give the title compound (18 g, 79% yield) as orange color solid. Mp 81° C. 1H NMR (300 MHz, CDCl3) δ 7.83 (d, J=8.6 Hz, 2H), 7.23 (d, J=8.6 Hz, 2H), 6.97 (s, 1H), 3.89 (s, 3H), 2.47 (s, 3H); 13C NMR (75 MHz, CDCl3). Mass spectrum (API-TIS) m/z 253 (MH+). Anal. calcd. for C12H12O4S: C, 57.13; H, 4.79; S, 12.71. Found: C, 56.85; H, 4.76; S, 12.43.

Source