Synthesis of 3,4-Di(oleyloxy) Benzoic Acid

3,4-Di(oleyloxy) Benzoic Acid 

suspend

 5.0 g (15.0 mmol) of oleyl bromide, http://www.trc-canada.com/product-detail/?CatNum=O532955, 1g    $150.00, 10g    $1200.00

1.24 g (6.8 mmol) of protocatechuic acid ethyl ester, (25 http://www.abcam.com/protocatechuic-acid-ethyl-ester-ab142938.html, 25 g $115)

2.8 g (20.4 mmol) of potassium carbonate,

and 0.13 g (0.8 mmol) of potassium iodide

in 40 mL of cyclohexanone

stir at 100 °C for 18 h under nitrogen. Because of the light sensitivity of oleyl bromide, the flask should be covered with aluminum foil.

Filter the hot reaction mixture

Remove solvent by a vacuum.

Dissolve the residue in 30 mL of ethanol containing 1.14 g (20 mmol) potassium hydroxide and refluxed for 4 h.

Add the hot reaction mixture to 80 mL of water.

Add concentrated hydrochloric acid to pH 1 acidify with the mixture 

this will result in the precipitation of a white solid.

Filter the solid  and wash several times with water.

Recrystallize the crude acid from 20 mL of ethanol and dry in a vacuum. 

Yield: 3.2 g (72%). mp: 60.5 °C.

Purify by TLC (silica gel) chloroform/methanol (9:1)

cationic lipids can be purified by column chromatography using silica gel 60 (Merck, 70-230 mesh) and dichloromethane (CH2Cl2)/methanol (MeOH) mixtures.