Реакция #1256701

Уравнение реакции

5-amino-3-methyl-1,2,4-thiadiazole

sodium nitrite

→

3-methyl-5-nitrosoamino-1,2,4-thiadiazole

Растворители

sulfuric acid

Условия реакции

Обработка

1. 1
   workup.ADDITIONAfter completion of dropwise addition
2. 2
   ДругоеThe crystals precipitated
3. 3
   Фильтрацияwere collected by filtration
4. 4
   Промывкаwashed with ice cold water
5. 5
   ДругоеThe crystals were dried in the air at room temperature overnight

Методика

First, 11.5 g (0.1 mol) of 5-amino-3-methyl-1,2,4-thiadiazole was dissolved in 100 mL of 2N sulfuric acid. While the mixture was stirred, an aqueous sodium nitrite solution (containing 8.0 g (0.116 mmol) of sodium nitrite in 20 mL of water) was added dropwise to the mixture at 0° C. or less. After completion of dropwise addition, the resultant solution was continuously stirred further for one hour at 0° C. The crystals precipitated were collected by filtration and washed with ice cold water. The crystals were dried in the air at room temperature overnight to obtain 8.5 g (56% in yield) of 3-methyl-5-nitrosoamino-1,2,4-thiadiazole. Next, 7.2 g (0.05 mol) of the obtained thiadiazole was dissolved in 50 mL of methanol at room temperature. While the resultant solution was stirred, 3 mL of concentrated sulfuric acid was added dropwise to the solution at 5° C. or less. After completion of dropwise addition, the solution was continuously stirred further at 5° C. or less for one hour or less and at 15 to 20° C. for 2 hours. The crystals precipitated were collected by filtration. The crystals were recrystallized from methanol to obtain 2.5 g (41% in yield) of triazene dissociative direct dye D-5.

Источник