| abstract |
A compound of ** Formula **, wherein R is an azido group, a hydroxy group, an unsubstituted or substituted guanidino group or an unsubstituted or substituted amino group; R2 is COCH3, COCF3, SO2CH3 or SO2CF3; X is O, O (C = O), NH, NHCO, O (C = O) NH, O (C = S) NH, NH (C = O) or NH (C = S) NH; and the spacer group Y is an optionally substituted and / or branched chain of up to 100 atoms in length, with the central axis atoms selected from the group consisting of carbon, nitrogen, oxygen and sulfur; or a pharmaceutically acceptable salt or derivative. |