Reacción #976826

Ecuación de reacción

(E)-4-(4-chloro-2-fluorophenyl)-but-3-en-2-one

diethyl oxalate

Sodium

ethyl alcohol

sodium

→

(E)-6-(4-chloro-2-fluoro-phenyl)-2,4-dioxo-hex-5-enoic acid ethyl ester

Rendimiento 86.5%

(E)-6-(4-chloro-2-fluorophenyl)-2,4-dioxo-hex-5-enoic acid ethyl ester

Rendimiento 86.5%

Disolventes

ether

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrothe solvent was removed under reduced pressure, and anhydrous ether (200 mL)
2. 2
   workup.ADDITIONwas added
3. 3
   Filtraciónthe yellow solid was filtered
4. 4
   Lavadowashed with ether
5. 5
   OtroAfter 1 hour (h) of drying at room temperature
6. 6
   Otrothe solid was partitioned between CH2Cl2 (200 mL) and 1 N sulfuric acid (H2SO4, 150 mL)
7. 7
   SecadoThe organic layer was dried (MgSO4)
8. 8
   Otrothe solvent was removed

Procedimiento

Sodium pellets (2.88 g, 0.125 mol) were slowly added to absolute ethyl alcohol (EtOH, 125 mL). After the sodium had reacted, the solvent was removed under reduced pressure, and anhydrous ether (200 mL) was added. The reaction mixture was cooled to −5° C., and a solution of (E)-4-(4-chloro-2-fluorophenyl)-but-3-en-2-one (1; 24.75 g, 0.125 mol) and diethyl oxalate (21.9 g, 0.15 mol) in anhydrous ether (25 mL) was added over 30 min. After stirring 2 days (d) at room temperature, the yellow solid was filtered and washed with ether. After 1 hour (h) of drying at room temperature, the solid was partitioned between CH2Cl2 (200 mL) and 1 N sulfuric acid (H2SO4, 150 mL). The organic layer was dried (MgSO4), and the solvent was removed to give (E)-6-(4-chloro-2-fluoro-phenyl)-2,4-dioxo-hex-5-enoic acid ethyl ester (3; 32.3 g, 86%) as a yellow solid. A small sample was recrystallized from EtOH to yield yellow crystals: mp 84-85° C.; 1H NMR (400 MHz, CDCl3) δ 14.72 (s, 1H), 7.76 (d, J=16.1 Hz, 1H), 7.49 (d, J=8.3 Hz, 1H), 7.24-7.12 (m, 2H), 6.73 (d, J=16.1 Hz, 1H), 6.53 (s, 1H), 4.38 (q, J=7.1 Hz, 2H), 1.40 (t, J=7.1 Hz, 3H); HRMS-ESI (m/z): calcd for C14H12ClFO4, 298.041. found, 298.041.

Fuente