Reaction #5358

Reaction equation

HCl

thiotetronic acid

1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride

linoleic acid

→

4-hydroxy-3-[(Z,Z)-1-oxo-9,12-octadecadienyl]-2(5H)-thiophenone

Yield 30.0%

Solvents

dimethylformamide

triethylamine

Conditions

Workup

1. 1
   Extractionextracted three times with diethyl ether
2. 2
   WashThe combined organic layers are washed with brine
3. 3
   Dryingdried over Na2SO4
4. 4
   Filtrationfiltered
5. 5
   Concentrationconcentrated in vacuo
6. 6
   OtherThe residue is recrystallized from pentane at -78° C.
7. 7
   Otherto give a solid which
8. 8
   Temperatureupon warming to room temperature

Procedure

To a stirring solution of 1.71 g (14.75 mmol) of thiotetronic acid in 10 mL of dimethylformamide is added 2.22 ML (17.2 mmol) of triethylamine and 592 mg (4.85 mmol) of 4-dimethylaminopyridine at 0° C. Next, 3.38 g (17.6 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 4.96 g (17.7 mmol) of linoleic acid are added and the reaction mixture is stirred overnight at room temperature. The reaction is acidified with 1.0N HCl and extracted three times with diethyl ether. The combined organic layers are washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo. The residue is recrystallized from pentane at -78° C. to give a solid which melts upon warming to room temperature giving 1.67 g (30%) of 4-hydroxy-3-[(Z,Z)-1-oxo-9,12-octadecadienyl]-2(5H)-thiophenone as an oil.

Source