Reacción #2074

Ecuación de reacción

adduct

Triphenylphosphonium (4-carboxymethoxyphenyl)methane

2-formylbenzenesulfonic acid

sodium

methanol

sodium methoxide

→

white powder

Trans-methyl 2'-Sodiosulfostilbene-4-carboxylate

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaThe solution is heated
2. 2
   Temperaturato reflux under argon
3. 3
   TemperaturaThe solution is heated
4. 4
   Temperaturaat reflux for 8 hrs
5. 5
   OtroMost of the methanol is removed on the rotary evaporator (~60° C.)
6. 6
   Otroforming a milky suspension
7. 7
   TemperaturaThe mixture is cooled in an ice bath
8. 8
   Filtraciónfiltered
9. 9
   ConcentraciónThe mother liquor is concentrated to ~800 mL on the rotary evaporator and refrigerated overnight
10. 10
    FiltraciónThe crystals which form are filtered
11. 11
    Otrodried
12. 12
    ConcentraciónThe water layer is concentrated

Procedimiento

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.

Fuente