Patent ID: 8034821

Claim:
A compound having the formula (I): in which: R 1 is NHR a wherein R a is hydrogen or an optionally substituted aliphatic, aromatic or heterocyclic group; R 2 is hydrogen or a group having the formula (CH 2 ) b R b wherein b is 0 or an integer from 1 to 3 and R b is an aromatic, heterocyclic or cyclical aliphatic group optionally substituted with one or more groups selected from lower alkyl, halogen, substituted alkyl, nitro, alkoxy, phenoxy, or sulfonamido; R 3 is hydrogen or an aliphatic, aromatic, or heterocyclic group; R 4 is an electrophilic group E; R 5 is hydrogen, alkoxy, alkylthio, alkylamino, aryloxy, arylthio, or arylamino; and E is —(CH 2 ) m COR′, —CO(CH 2 ) n R′, —C(O)C(O)R′, an epoxide, or an olefin attached to an electron withdrawing group, wherein m and n are independently 0 or an integer from 1 to 6, wherein R′ is independently hydrogen, halogen, amino, substituted amino, cyano, an optionally substituted aliphatic, an optionally substituted aromatic, or an optionally substituted heterocyclic group.