Editing Synthesis Lipophilic Polyamines (section)

== DCC-mediated esterification of fatty acids (Steglich esterification)<br>  ==

The Steglich esterification is a variation of an esterfication with dicyclohexylcarbodiimide as a coupling reagent and 4-dimethylaminopyridine as a catalyst. The reaction was first described by Wolfgang Steglich in 1978.[1] It is an adaptation of an older method for the formation of amides by means of DCC (dicyclohexylcarbodiimide) and 1-hydroxybenzotriazole (HOBT).[2][3]<br>

[[Image:Steglich_esterification.png]]<br>This reaction generally takes place at room temperature. A suitable solvent is dichloromethane. Because the reaction is mild, esters can be obtained that are inaccessible through other methods for instance esters of the sensitive 1,4-dihydroxybenzoic acid. A characteristic is the formal uptake of water generated in the reaction by DCC, forming the urea compound dicyclohexylurea (DCU).



[[Image:Lipid_esterification.png]]

Add&nbsp;<span style="line-height: 1.5em;">DCC (3.61g,11&nbsp;</span><span style="line-height: 1.5em;">mmole) and DMAP (1.22g, 10 mmole) in dichloro</span><span style="line-height: 1.5em;">methane (50 mL)</span><span style="line-height: 1.5em;">&nbsp;to&nbsp;</span>a solution of fatty acid &nbsp;( e.g., 1.84g, 10 mmole), alcohol&nbsp;2 or 3 (2.56g or 3.28g, 10 mmole), 

Stir mechanically at room&nbsp;temp. The progress of the reaction is monitored by&nbsp;TLC.

After the completion of reaction the N,N ′ -dicyclohexylurea (DHC) is filtered off 

Wash &nbsp;the&nbsp;filtrate &nbsp;with water (3 × 50 mL), 5% acetic&nbsp;acid solution (3 × 50 mL), again with water (3 × 50&nbsp;mL)

Dry the liquid over anhydrous sodium sulphate.<br>Evaporate the solvent &nbsp;under reduced pressure to&nbsp;give the crude product (liquid),

Purify lipid by flash chromatograph over a column of silica gel. Elution with petether-diethyl ether (98:2, v/v) to yield the ester.