Reaction #362825

Reaction equation

potassium iodide

sodium nitrite

hydrochloric acid

3-methylthioaniline

→

3-iodo-1-methylthiobenzene

Solvents

water

water

water

Conditions

Workup

1. 1
   TemperatureThe mixture is warmed
2. 2
   workup.DISSOLUTIONdissolution
3. 3
   workup.ADDITIONare subsequently added slowly
4. 4
   Temperaturewhile maintaining the temperature between 5 and 8° C
5. 5
   Other20 min
6. 6
   workup.ADDITIONare added over a period of 10 min
7. 7
   workup.STIRRINGthe mixture is then stirred at room temperature for 15 h
8. 8
   OtherThe oil which forms is separated from the aqueous phase by decantation
9. 9
   workup.ADDITIONan aqueous solution of sodium thiosulphate is then added to it
10. 10
    OtherThe aqueous phase is decanted
11. 11
    Extractionthe product is extracted with 100 ml of dichloromethane
12. 12
    WashThe organic phase is washed with 100 ml of water
13. 13
    Otherseparated off
14. 14
    WashThe organic phase is washed with 2 times 100 ml of water
15. 15
    Otherseparated off
16. 16
    Dryingdried over magnesium sulphate
17. 17
    Filtrationfiltered
18. 18
    Concentrationconcentrated to dryness under reduced pressure (50 kPa) at 40° C
19. 19
    OtherThe resulting product is purified by flash chromatography (eluent, cyclohexane) in order

Procedure

20 ml of distilled water and 20 ml of 12 N hydrochloric acid are placed, with stirring, in a three-necked flask, and 10 ml of 3-methylthioaniline are then added using a dropping funnel. The mixture is warmed to ensure dissolution and is then cooled down to 5° C. 5.86 g of sodium nitrite dissolved in 15 ml of water are subsequently added slowly, using a dropping funnel, while maintaining the temperature between 5 and 8° C. 20 min after having completed the addition, 13.57 g of potassium iodide dissolved in 15 ml of water are added over a period of 10 min and the mixture is then stirred at room temperature for 15 h. The oil which forms is separated from the aqueous phase by decantation, and an aqueous solution of sodium thiosulphate is then added to it. The aqueous phase is decanted and the product is extracted with 100 ml of dichloromethane. The organic phase is washed with 100 ml of water, and the aqueous phase is adjusted to pH 9 with concentrated sodium hydroxide solution, and then separated off. The organic phase is washed with 2 times 100 ml of water, separated off, dried over magnesium sulphate, filtered and then concentrated to dryness under reduced pressure (50 kPa) at 40° C. The resulting product is purified by flash chromatography (eluent, cyclohexane) in order to yield 13 g of 3-iodo-1-methylthiobenzene in the form of a yellow liquid (Merck Silica 5719, Rf=0.8/cyclohexane).

Source