Reacción #214173

Ecuación de reacción

glyoxylic acid

glyoxylic acid

2-acetylthiophene

→

title compound

Rendimiento 52.5%

4-(2-Thienyl)-4-oxocrotonic acid

Rendimiento 52.5%

Disolventes

water

water

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturaheating
2. 2
   workup.STIRRINGstirring
3. 3
   Temperaturaare maintained for about 5 hours
4. 4
   Otrois removed by means of a Dean-Stark apparatus
5. 5
   TemperaturaOn cooling the residue solidifies
6. 6
   workup.DISSOLUTIONIt is dissolved in 100 cc ether
7. 7
   Extracciónextracted with 150 cc of a 20% solution of Na2CO3
8. 8
   workup.ADDITIONThis aqueous solution is treated with activated charcoal
9. 9
   Filtraciónfiltered
10. 10
    FiltraciónThe solid is filtered
11. 11
    workup.DISSOLUTIONdissolved in about 1 L ether
12. 12
    SecadoThe ether is dried over MgSO4
13. 13
    Otroremoved

Procedimiento

A two phase mixture of 18 grams glyoxylic acid (an 80% solution of glyoxylic acid in water) and 25.2 grams of 2-acetylthiophene is heated to 125° C. with stirring, and heating and stirring are maintained for about 5 hours. A clear solution forms at 115° C. and the water formed is removed by means of a Dean-Stark apparatus. On cooling the residue solidifies. It is dissolved in 100 cc ether and extracted with 150 cc of a 20% solution of Na2CO3. This aqueous solution is treated with activated charcoal, filtered and made strongly acid with 20% HCl. The solid is filtered and dissolved in about 1 L ether. The ether is dried over MgSO4 and removed to yield 19.1 g of the title compound, melting point 139°-142° C.

Fuente