Reaction #54833

Reaction equation

ethyl 3-amino-4-cyclohexylphenylglyoxylate

potassium ethyl xanthate

sodium nitrite

hydrochloric acid

→

3-mercapto-4-cyclohexylphenylglyoxylic acid

Solvents

water

water

Conditions

Workup

1. 1
   workup.ADDITIONof ice is added 4.1 g
2. 2
   TemperatureThe reaction is gradually heated over 45 minutes to 50° C.
3. 3
   workup.STIRRINGstirred an additional 45 minutes
4. 4
   TemperatureThe mixture is then cooled
5. 5
   Extractionextracted with ether which
6. 6
   Washis then washed with water, dilute sodium hydroxide and water
7. 7
   Dryingdried over sodium sulfate
8. 8
   workup.DISSOLUTIONThe residue is dissolved in 35 ml
9. 9
   workup.ADDITIONof boiling ethanol to which is added gradually 13 g
10. 10
    TemperatureThe reaction is refluxed an additional hour
11. 11
    Otherevaporated to dryness in vacuo
12. 12
    workup.DISSOLUTIONThe residue is dissolved in water
13. 13
    Extractionextracted with ether
14. 14
    Extractionextracted with ether
15. 15
    WashThe ether is washed with water
16. 16
    Dryingdried over sodium sulfate
17. 17
    Otherevaporated to dryness

Procedure

To 17.3 g. of ethyl 3-amino-4-cyclohexylphenylglyoxylate in 11.1 ml. of concentrated hydrochloric acid and 20 g. of ice is added 4.1 g. of sodium nitrite in 2 ml. of water. This mixture is stirred for 10 min. and then added gradually to an ice cold solution of 10.3 g. of potassium ethyl xanthate in 14 ml. of water. The reaction is gradually heated over 45 minutes to 50° C. and stirred an additional 45 minutes. The mixture is then cooled, extracted with ether which is then washed with water, dilute sodium hydroxide and water, dried over sodium sulfate and evapoated in vacuo. The residue is dissolved in 35 ml. of boiling ethanol to which is added gradually 13 g. of potassium hydroxide. The reaction is refluxed an additional hour and then evaporated to dryness in vacuo. The residue is dissolved in water and extracted with ether. The alkaline phase is acidified with 6N sulfuric acid and extracted with ether. The ether is washed with water, dried over sodium sulfate and evaporated to dryness to obtain 3-mercapto-4-cyclohexylphenylglyoxylic acid.

Source