Reacción #979039

Ecuación de reacción

sodium acetate trihydrate

1,1-dibromo-3,3,3-trifluoroacetone

NaOH

aminoguanidine bicarbonate

→

mixture

Rendimiento 53.1%

3-Amino-5-trifluoromethyl-1,2,4-triazine

Rendimiento 53.1%

Disolventes

water

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaThe solution was heated
2. 2
   Temperaturaat reflux under nitrogen for 30 min
3. 3
   FiltraciónThe solid was collected by filtration
4. 4
   Lavadowashed with water
5. 5
   Otrodried at 60° C. under vacuum

Procedimiento

To a stirred solution of sodium acetate trihydrate (22.62 g, 166.2 mmol) in water (80 ml) was added 1,1-dibromo-3,3,3-trifluoroacetone (21.57 g, 79.9 mmol). The solution was heated at reflux under nitrogen for 30 min, then allowed to cool to room temperature before adding solid aminoguanidine bicarbonate (10.88 g, 79.9 mmol). The resulting pale yellow solution (pH 5) was stirred at room temperature for 3 h, then 4 N aqueous NaOH solution (40 ml, 160 mmol) was added causing a precipitate to appear. The mixture (pH 10) was stirred under nitrogen for a further 39 h. The solid was collected by filtration, washed with water and dried at 60° C. under vacuum to give 6.96 g of a mixture of two isomers in a 28:72 ratio. This was further purified by flash chromatography (silica gel, 30% EtOAc/isohexane), then recrystallised from ethanol to afford 3.53 g (27%) of the title compound: 1H NMR (400 MHz, DMSO-d6) δ 8.00 (2H, br s), 9.08 (1H, s).

Fuente