Reaktion #2074

Reaktionsgleichung

adduct

Triphenylphosphonium (4-carboxymethoxyphenyl)methane

2-formylbenzenesulfonic acid

sodium

methanol

sodium methoxide

→

white powder

Trans-methyl 2'-Sodiosulfostilbene-4-carboxylate

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe solution is heated
2. 2
   Temperaturto reflux under argon
3. 3
   TemperaturThe solution is heated
4. 4
   Temperaturat reflux for 8 hrs
5. 5
   SonstigeMost of the methanol is removed on the rotary evaporator (~60° C.)
6. 6
   Sonstigeforming a milky suspension
7. 7
   TemperaturThe mixture is cooled in an ice bath
8. 8
   Filtrationfiltered
9. 9
   EinengenThe mother liquor is concentrated to ~800 mL on the rotary evaporator and refrigerated overnight
10. 10
    FiltrationThe crystals which form are filtered
11. 11
    Sonstigedried
12. 12
    EinengenThe water layer is concentrated

Vorschrift

To 146 gm (0.327 mol) of the adduct prepared in Example 10 in a 2 L, three-neck round bottom flask equipped with a magnetic stirring bar, condenser, addition funnel, and thermometer connected to a temperature controlling device (Thermowatch, I2R), is added 2-formylbenzenesulfonic acid, sodium salt, hydrate (Aldrich, 80 gm, ~0.35 mol), and methanol (Baker, ~900 gm). The solution is heated to reflux under argon, and sodium methoxide (Aldrich, 80.8 gm of 25% solution in methanol, 0.374 mol) is added from the addition funnel over ~15 min. The solution is heated at reflux for 8 hrs. A 13 C-NMR (DMSO-d6) shows the disappearance of the peaks for starting material at ~28.5 ppm and 29 ppm [--CH2P(C6 H5)3 ]. Most of the methanol is removed on the rotary evaporator (~60° C.). The remaining material is taken up in ~500 mL water, forming a milky suspension. The mixture is adjusted to pH 7 with a few drops of methanesulfonic acid (Aldrich). The mixture is cooled in an ice bath and filtered. A 13C-NMR (DMSO-d6) shows the isolated solid to be mainly triphenylphosphine oxide. The mother liquor is concentrated to ~800 mL on the rotary evaporator and refrigerated overnight. The crystals which form are filtered, dried, and stirred vigorously in hot 50:50 water:toluene. The water layer is concentrated to afford 20 gm of white powder. The combination of 13C-NMR, 1 H-NMR, C.O.S.Y. and N.O.E. indicates that the material is a 60:40 mixture of trans:cis isomers of the substituted stilbene compound.

Quelle