Reaktion #657206

Reaktionsgleichung

p-toluene sulfonic acid

pyruvic acid

methyl carbamate

water

hydroquinone

→

alpha-(methoxycarbonylamino)-acrylic acid

Lösungsmittel

benzene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturis refluxed in a 100 ml round bottom flask to which
2. 2
   SonstigeThe system is exposed to air during the reaction
3. 3
   Temperaturwhile warm
4. 4
   Temperaturupon cooling
5. 5
   FiltrationThe suspension is filtered
6. 6
   Sonstigeis evaporated

Vorschrift

A solution pyruvic acid (4.40 g, 50.0 mmol), methyl carbamate (3.75 g, 50.0 mmol), hydroquinone (used for a polymerization inhibitor, 0.05 g), and p-toluene sulfonic acid (50 mg) in 30 ml benzene is refluxed in a 100 ml round bottom flask to which is attached a Dean-Stark trap. The system is exposed to air during the reaction. After 2 hours, 25 minutes, 0.60 ml water (33 mmol) accumulates in the trap. The yellow solution is hazy while warm, but a small amount of gelatinous precipitate accumulated upon cooling. The suspension is filtered and is evaporated. Proton nuclear magnetic resonance spectrosopy confirms the presence of the title compound; (CDCl3, ppm) 10.0-10.5 (1H, broad singlet), 5.4 (1H, broad singlet), 5.1 (1H, broad singlet), 4.5-5.0 (1H, broad singlet), 3.9 (3H, singlet).

Quelle