Reacción #162941

Ecuación de reacción

N-hydroxy-4-nitro-benzimidoyl chloride

ethyl propiolate

Et3N

→

title compound

Rendimiento 51.7%

3-(4-Nitro-phenyl)-isoxazol-5-carboxylic acid ethyl ester

Rendimiento 51.7%

Disolventes

toluene

EtOAc

Condiciones de reacción

Tratamiento posterior

1. 1
   OtroThe resulting reaction mixture
2. 2
   Otrotransferred in a separating funnel
3. 3
   LavadoThe EtOAc layer was washed with 0.1N HCl (10 ml)
4. 4
   SecadoThe EtOAc layer was dried over anhydrous Na2SO4, solvent
5. 5
   Otrowas evaporated
6. 6
   Otrothe residue was crystallized from CHCl3 and light petroleum

Procedimiento

To a solution of N-hydroxy-4-nitro-benzimidoyl chloride (2.0 g; 10 mmol) and ethyl propiolate (2.02 ml; 20 mmol) in toluene (25 ml) was added Et3N (1.46 ml; 10.5 mmol) drop wise for 10 minutes. The resulting reaction mixture was heated at 80° C. for 2.5 hours, and then diluted with EtOAc (50 ml) and transferred in a separating funnel. The EtOAc layer was washed with 0.1N HCl (10 ml) followed by water (3×10 ml) and brine (10 ml). The EtOAc layer was dried over anhydrous Na2SO4, solvent was evaporated and the residue was crystallized from CHCl3 and light petroleum to afford the title compound of step 1 (1.35 g; 51.7%). Mass (ES+), 263 (M++1); 1H NMR (CDCl3) δ: 1.45 (t, 3H), 4.48 (q, 2H), 7.26 (s, 1H), 8.02 (d, 2H), 8.35 (d, 2H).

Fuente