Reaktion #55230

Reaktionsgleichung

pinacolone

NaOH

HCl

dimethylamine

dimethylamine

thiocarbohydrazide

sulfur dichloride

→

6-tert.-butyl-3-mercapto-4-amino-1,2,4-triazin-5(4H)-one

Lösungsmittel

water

water

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooling slightly
2. 2
   workup.STIRRINGAfter the mixture had been further stirred for 1 hour at 40° C.
3. 3
   Sonstigeover the course of about 30 minutes
4. 4
   workup.STIRRINGthe mixture was stirred for a further 30 minutes at the same temperature
5. 5
   Temperaturthe mixture was heated
6. 6
   Temperaturunder reflux for 4-6 hours
7. 7
   Sonstigebeing absorbed in water
8. 8
   TemperaturAfter cooling to 60°-70° C.
9. 9
   Sonstigebeing absorbed in sodium hydroxide solution) and elemental sulfur, which
10. 10
    Sonstigehad precipitated at the same time
11. 11
    Filtrationwas filtered off
12. 12
    Sonstigethe mixture was reacted at pH 1 and 50°-80° C.

Vorschrift

100 g of pinacolone (1 mole) were initially introduced into a stirred flask and 154.5 g (1.5 moles) of sulfur dichloride were added dropwise in the course of 2 hours at 20°-40° C., whilst stirring and cooling slightly, HCl being released via a condenser. After the mixture had been further stirred for 1 hour at 40° C., a solution of 90 g (2 moles) of dimethylamine in water (as an approximately 40% strength solution) was allowed to run in, over the course of about 30 minutes, at 60°-80° C., while cooling with water and the mixture was stirred for a further 30 minutes at the same temperature. A solution of 140 g (3.5 moles) of NaOH in 300 ml of water was then added and the mixture was heated under reflux for 4-6 hours, dimethylamine being released as a gas via the condenser and being absorbed in water. After cooling to 60°-70° C., the pH of the mixture was adjusted to 3.0 with hydrochloric acid (hydrogen sulfide being released as a gas and being absorbed in sodium hydroxide solution) and elemental sulfur, which had precipitated at the same time, was filtered off. 106 g (1.0 mole) of thiocarbohydrazide were added to the clear filtrate and the mixture was reacted at pH 1 and 50°-80° C. to give 6-tert.-butyl-3-mercapto-4-amino-1,2,4-triazin-5(4H)-one. This was very sparingly soluble in the reaction medium and could easily be isolated by filtering off. Yield: 150 g (or 75% of theory).

Quelle