Reaktion #697947

Reaktionsgleichung

hydrochloric acid

methyl 2-nitro-4-methylsulphonylbenzoate

→

methyl 2-amino-4-methylsulphonylbenzoate

Ausbeute 20.4%

Lösungsmittel

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe cooling bath was then removed
2. 2
   workup.ADDITIONiron dust (17.5 g) was added portionwise over a period of 20 minutes
3. 3
   Sonstigedid not exceed 50° C
4. 4
   TemperaturAfter 15 minutes of cooling
5. 5
   Sonstigethe bath was removed
6. 6
   Sonstigeto reach room temperature
7. 7
   workup.ADDITIONThe mixture was poured onto ice
8. 8
   workup.ADDITIONDichloromethane was added
9. 9
   Filtrationthe suspension was filtered
10. 10
    ExtraktionThe filtrate was extracted with further dichloromethane
11. 11
    Trocknenthe combined organic extracts were dried (magnesium sulphate)
12. 12
    Filtrationfiltered
13. 13
    Sonstigeevaporated
14. 14
    Sonstigeto yield a crude product which
15. 15
    Sonstigewas purified by recrystallisation from ethyl acetate/hexane

Vorschrift

Concentrated hydrochloric acid (90 ml) was added to a stirred suspension of methyl 2-nitro-4-methylsulphonylbenzoate (25 g) in methanol at -5° C. (ice/salt bath). The cooling bath was then removed and iron dust (17.5 g) was added portionwise over a period of 20 minutes. The resulting exotherm was controlled using a cooling bath so that the temperature did not exceed 50° C. After 15 minutes of cooling, the bath was removed and the reaction mixture was allowed to reach room temperature. Stirring was continued for a further 3 hours. The mixture was poured onto ice and then neutralised with sodium carbonate. Dichloromethane was added and the suspension was filtered. The filtrate was extracted with further dichloromethane and the combined organic extracts were dried (magnesium sulphate), filtered and evaporated to yield a crude product which was purified by recrystallisation from ethyl acetate/hexane to give methyl 2-amino-4-methylsulphonylbenzoate (4.5 g) as yellow needles, m.p. 98.3-98.5° C.

Quelle