How can I remove DCU (dicyclohexyl urea) by product formed during estrification reaction via (DCC/DMAP) with carboxylic acids?

The problem is with the purification of the single product; I did purify my desired compound by precipitation with toulene because I did synthesize PGG (pent O-galloyl glucose). In NMR it shows...

23 April 2013 4,210 21 View