Reacción #995

Ecuación de reacción

sodium hydroxide

potassium hydroxide

cyclohexanedione

ethyl bromopyruvate

→

4-oxo-4,5,6,7-tetrahydrobenzofuran-3-carboxylic acid

Disolventes

methyl alcohol

methyl alcohol

water

methyl alcohol

Condiciones de reacción

Tratamiento posterior

1. 1
   Otro4-Oxo-4,5,6,7-tetrahydrobenzofuran-3-carboxylic acid was prepared
2. 2
   workup.STIRRINGto stir at ambient temperature for 17 h
3. 3
   workup.STIRRINGstirring
4. 4
   workup.WAITcontinued an additional 7 h
5. 5
   Otrothe methanol removed in vacuo
6. 6
   workup.ADDITIONIce water was added
7. 7
   Filtraciónthe precipitate filtered
8. 8
   Otrodried in vacuo

Procedimiento

4-Oxo-4,5,6,7-tetrahydrobenzofuran-3-carboxylic acid was prepared as follows: To a stirred solution of potassium hydroxide (28.06 g, 0.5 mol) in methyl alcohol (100 mL) under nitrogen at 0° C. was added dropwise a solution of cyclohexanedione (56.07 g, 0.5 mol) in methyl alcohol (100 mL). The mixture was stirred at 0° C. for 0.5 h, then a solution of ethyl bromopyruvate (66 mL, 0.525 mol) in methyl alcohol(100 mL) was added dropwise. After allowing the mixture to stir at ambient temperature for 17 h, a 50% aqueous sodium hydroxide solution (60 mL) was added dropwise and stirring continued an additional 7 h. After dilution with water, the solution was acidified and the methanol removed in vacuo. Ice water was added and the precipitate filtered and dried in vacuo to afford 4-oxo-4,5,6,7-tetrahydrobenzofuran-3-carboxylic acid. m.p. 137°-138° C.

Fuente