Reacción #1256702

Ecuación de reacción

5-amino-4-cyano-3-methylisothiazole

sodium nitrite

water

→

4-cyano-3-methyl-5-nitrosoaminoisothiazole

Disolventes

formic acid

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONAfter completion of dropwise addition
2. 2
   workup.STIRRINGthe mixture was continuously stirred at 0° C. further for one hour
3. 3
   Otroto precipitate crystals, which
4. 4
   Filtraciónwere collected by filtration
5. 5
   Lavadowashed with ice cold water
6. 6
   OtroThe crystals were dried in the air at room temperature overnight

Procedimiento

First, 4 g (0.028 mol) of 5-amino-4-cyano-3-methylisothiazole was dissolved in 40 mL of 98% formic acid. While the mixture was stirred, an aqueous sodium nitrite solution (containing 2.1 g (0.03 mmol) of sodium nitrite in 6 mL of water) was added dropwise at 0° C. or less. After completion of dropwise addition, the mixture was continuously stirred at 0° C. further for one hour. To the solution, 100 mL of water was added to precipitate crystals, which were collected by filtration and washed with ice cold water. The crystals were dried in the air at room temperature overnight to obtain 2.6 g (56% in yield) of 4-cyano-3-methyl-5-nitrosoaminoisothiazole. To 2 g (0.012 mol) of the obtained nitrosoaminoisothiazole, 20 mL of methanol was added, stirred while heating to an inner temperature of 55 to 60° C. for one hour and cooled to room temperature to precipitate crystals, which were collected by filtration. The crystals were recrystallized from methanol to obtain 0.66 g (41% in yield) of triazene dissociative direct dye D-34.

Fuente