Reaktion #55727

Reaktionsgleichung

hyrochloric acid

5-iodoanthranilic acid

sodium hydroxide

sodium nitrite

hydrochloric acid

potassium ethyl xanthate

nitrite

sodium hydroxide

potassium acetate

→

5-iodothiosalicyclic acid

Ausbeute 80.5%

Lösungsmittel

water

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas maintained between 0° and 5°
2. 2
   Temperaturby external cooling and by the addition of ice
3. 3
   Sonstigepreheated to 75°-80°
4. 4
   Temperaturthe reaction mixture was cooled
5. 5
   SonstigeAfter decanting the aqueous phase
6. 6
   workup.DISSOLUTIONthe resulting sludge was dissolved in 10 percent sodium hydroxide solution (200 ml)
7. 7
   Temperaturheated on a steam bath for two hours
8. 8
   TemperaturThe solution was cooled
9. 9
   Filtrationfiltered
10. 10
    Sonstigethe solid collected
11. 11
    Waschenwashed
12. 12
    Sonstigedried
13. 13
    TemperaturThe resulting disulfide was refluxed for 16 hours with zinc dust (25 g) in glacial acetic acid (750 ml)
14. 14
    SonstigeThe solid was collected
15. 15
    Waschenwashed with cold water
16. 16
    workup.WAITdigested with concentrated hydrochloric acid for 30 minutes
17. 17
    Filtrationfiltered
18. 18
    Waschenwashed with water
19. 19
    Sonstigedried

Vorschrift

A solution of 5-iodoanthranilic acid (71.1 g; 0.272 mole), sodium hydroxide (11.5 g; 0.275 mole) and sodium nitrite (18.75 g; 0.275 mole) in water (325 ml) was added slowly with stirring to a mixture of concentrated hydrochloric acid (75 ml) and ice (100 g) while the temperature was maintained between 0° and 5° by external cooling and by the addition of ice. After completion of the addition of the nitrite solution, the mixture was stirred for an additional 30 minutes and adjusted to pH 7 with dilute sodium hydroxide solution and potassium acetate. The cold diazonium mixture was added to a vigorously stirred solution of potassium ethyl xanthate (125 g; 0.775 mole) in water (400 ml) preheated to 75°-80°. When the evolution of nitrogen ceased, the reaction mixture was cooled and acidified to pH 3 with concentrated hyrochloric acid. After decanting the aqueous phase, the resulting sludge was dissolved in 10 percent sodium hydroxide solution (200 ml) and heated on a steam bath for two hours. The solution was cooled, filtered, acidified to pH 4-5 with concentrated hydrochloric acid, and the solid collected, washed and dried. The resulting disulfide was refluxed for 16 hours with zinc dust (25 g) in glacial acetic acid (750 ml). The solid was collected, washed with cold water, digested with concentrated hydrochloric acid for 30 minutes, filtered, washed with water and dried to give 5-iodothiosalicyclic acid (61.3 g), m.p. 208°-210°. Treatment of 5-iodothiosalicyclic acid (60 g) with acetic anhydride (300 ml) and concentrated sulfuric acid (1 ml) at 100° for one hour yielded 5-iodoacetylthiosalicylic acid (35.1 g), m.p. 163°14 165°.

Quelle