Reacción #589074

Ecuación de reacción

ethyl acetate hexane

Sodium hydroxymethanesulfinate

potassium carbonate

→

sultine

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

Disolventes

methanol ethyl acetate

DMSO

DMSO

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.WAITleft
2. 2
   workup.ADDITIONwere added consecutively
3. 3
   Lavadoto rinse residual materials into the reaction mixture before the whole
4. 4
   OtroThe initial endothermic reaction
5. 5
   Otroto rise to ca. 32-33° C
6. 6
   OtroThe reaction
7. 7
   workup.WAITto be complete after 3 h
8. 8
   Filtraciónthe solids were filtered off
9. 9
   Lavadowashed with more methanol/ethyl acetate (20:80; 100 mL, 2×50 mL)
10. 10
    OtroThe filtrate was transferred to a separating funnel
11. 11
    workup.ADDITIONbrine (1 L) was added
12. 12
    Otroto 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
    Otrothe organic layer was separated
17. 17
    Extracciónthe aqueous layer was extracted further with methanol/ethyl acetate (20:80; 200 mL, 150 mL, 250 mL)
18. 18
    SecadoThe combined extracts were dried (Na2SO4)
19. 19
    Otrorotary evaporated (bath 37-38° C.)
20. 20
    OtroMore solvent was removed under high vacuum

Procedimiento

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).

Fuente