Compounds of Formula (Ia)wherein R is a C6-C12 substituted or unsubstituted aryl, a C6-C12 substituted or unsubstituted heteroaryl, a C1-C6 substituted or unsubstituted alkyl or -NR'R',Q is C(O), O, NR', S, S(O)2, C(O)2(CH2)pY is C(O), O, NR', S, S(O)2, C(O)2(CH2)pZ is H or C1-C4 alkyl,R' is H, C(O), S(O)2, C(O)2, a C6-C12 substituted or unsubstituted aryl, a C6-C12 substituted or unsubstituted heteroaryl or a C1-C6 substituted or unsubstituted alkyl,when substituted, aryl, heteroaryl and alkyl are substituted with halogen, C6-C12 heteroaryl, - NR'R' or COOZ, which have diagnostic and therapeutic properties, such as the treatment and management of prostate cancer and other diseases related to NAALADase inhibition. Radiolabels can be incorporated into the structure through a variety of prosthetic groups attached at the X amino acid side chain via a carbon or hetero atom linkage.
