Synthesis of PAMAM Dendrimers Loaded with Mycophenolic Acid to Be Studied as New Potential Immunosuppressants

The terminal N-Boc protected diamino PAMAM 7 was condensed (EDC-DMAP) with two units of mycophenolic acid (MPA) giving the N-Boc protected dendron 8 in a good yield (76%). The ammonium trifluoroacetate 9 was prepared from 8 by acid treatment (TFA-THF-H2O) and was split into two equal parts. The first half was treated with di-2-pyridyl thionocarbonate (DPT) in the presence of Et3N to give the corresponding isothiocyanate 10. This was reacted with the second half of 9 providing the symmetrical dendrimer 11 (68% yield), exposing four MPA units around the thioureido-PAMAM core.