Reaktion #589074

Reaktionsgleichung

ethyl acetate hexane

Sodium hydroxymethanesulfinate

potassium carbonate

→

sultine

1,4-dihydro-2,3-benzoxathiin-3-oxide

Lösungsmittel

methanol ethyl acetate

DMSO

DMSO

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITleft
2. 2
   workup.ADDITIONwere added consecutively
3. 3
   Waschento rinse residual materials into the reaction mixture before the whole
4. 4
   SonstigeThe initial endothermic reaction
5. 5
   Sonstigeto rise to ca. 32-33° C
6. 6
   SonstigeThe reaction
7. 7
   workup.WAITto be complete after 3 h
8. 8
   Filtrationthe solids were filtered off
9. 9
   Waschenwashed with more methanol/ethyl acetate (20:80; 100 mL, 2×50 mL)
10. 10
    SonstigeThe filtrate was transferred to a separating funnel
11. 11
    workup.ADDITIONbrine (1 L) was added
12. 12
    Sonstigeto precipitate out
13. 13
    workup.ADDITIONThe addition of water (200 mL)
14. 14
    workup.DISSOLUTIONredissolved the sodium chloride
15. 15
    workup.STIRRINGThe mixture was shaken
16. 16
    Sonstigethe organic layer was separated
17. 17
    Extraktionthe aqueous layer was extracted further with methanol/ethyl acetate (20:80; 200 mL, 150 mL, 250 mL)
18. 18
    TrocknenThe combined extracts were dried (Na2SO4)
19. 19
    Sonstigerotary evaporated (bath 37-38° C.)
20. 20
    SonstigeMore solvent was removed under high vacuum

Vorschrift

Sodium hydroxymethanesulfinate (Rongalite™) (180 g; 1.17 mol) was suspended in DMSO (400 mL) and left to stir for 10 min. before dicholoro-o-xylene (102.5 g; 0.59 mol), potassium carbonate (121.4 g; 0.88 mol) and sodium iodide (1.1 g; 7 mmol) were added consecutively. More DMSO (112 mL) was used to rinse residual materials into the reaction mixture before the whole was allowed to stir at room temperature. The initial endothermic reaction became mildly exothermic after around 1 h causing the internal temperature to rise to ca. 32-33° C. The reaction as followed by TLC (ethyl acetate/hexane, 50:50) and found to be complete after 3 h. The reaction mixture was diluted with methanol/ethyl acetate (20:80; 400 mL) and the solids were filtered off, and washed with more methanol/ethyl acetate (20:80; 100 mL, 2×50 mL). The filtrate was transferred to a separating funnel and brine (1 L) was added. This caused more sodium chloride from the product mixture to precipitate out. The addition of water (200 mL) redissolved the sodium chloride. The mixture was shaken and the organic layer was separated and then the aqueous layer was extracted further with methanol/ethyl acetate (20:80; 200 mL, 150 mL, 250 mL). The combined extracts were dried (Na2SO4) and rotary evaporated (bath 37-38° C.). More solvent was removed under high vacuum to give the sultine 10 as a pale orange liquid (126 g) that was found by 1H NMR spectroscopy to be relatively free of by-product but containing residual DMSO and ethyl acetate (FIG. 1).

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