The present invention relates to novel compounds, compositions comprising said compounds, and uses thereof, said compounds having the formula: ##STR1##

wherein each X is independently selected from:

i) —C(W)₂—;

ii) —C(O)—;

iii) —NR²—;

iv) —S—;

v) —S(O)—;

vi) —S(O)₂—;

vii) two units, one from each adjacent X unit, can be taken together to form a substituted or unsubstituted double bond having the formula —CWCW—; wherein each W is hydrogen of a unit having the formula —(L²)_j—R², the index j is 0 or 1;

R is a carbocyclic or heterocyclic aryl ring;

R¹ is a cysteine trap;

each R² is independently a suitable substituent; and

L, L¹, and L² are linking units.