Reacción #742297

Ecuación de reacción

2-(Ethoxymethylene)malononitrile

(2,6-Dichlorophenyl)hydrazine hydrochloride

NaOH

→

product

Rendimiento 94.5%

5-amino-1-(2,6-dichlorophenyl)-1H-pyrazole-4-carbonitrile

Rendimiento 94.5%

Disolventes

EtOAc

Condiciones de reacción

Tratamiento posterior

1. 1
   OtroThe organic layer separated
2. 2
   Lavadowashed with water (50 mL), brine (50 mL)
3. 3
   Secadodried (MgSO4)
4. 4
   Filtraciónfiltered
5. 5
   Concentraciónconcentrated
6. 6
   Otrowas suspended in methanol (50 mL) under nitrogen at −5° C
7. 7
   Temperaturaheated
8. 8
   Temperaturaat reflux under nitrogen for 2 hours
9. 9
   Temperaturato cool
10. 10
    Otroevaporated to dryness

Procedimiento

(2,6-Dichlorophenyl)hydrazine hydrochloride (5 g, 23.42 mmol) was partitioned between EtOAc (100 mL) and NaOH (2M, aq) (40 mL). The organic layer separated and washed with water (50 mL), brine (50 mL), dried (MgSO4), filtered and concentrated. The resultant oil was suspended in methanol (50 mL) under nitrogen at −5° C. 2-(Ethoxymethylene)malononitrile (2.86 g, 23.42 mmol) added portion-wise over 5 mins and the mixture stiffed at 0° C. for 30 mins. The reaction mixture was allowed to warm to room temperature and then heated at reflux under nitrogen for 2 hours. The reaction mixture was allowed to cool and evaporated to dryness to afford the product (5.60 g, 94%) which was used without further purification. 1H NMR (400 MHz, CDCl3) δ 4.47 (2H, s), 7.43-7.47 (1H, m), 7.51-7.53 (2H, m), 7.73 (1H, s); m/z (ES+) (M+H)+=253; HPLC tR=1.62 min. Alternatively the product was obtained by concentrating the reaction mixture to half volume and allowing the product to crystallise.

Fuente