Patent ID: 6916925

Claim:
A compound of the formula (I): wherein: R 1 is a spacer group selected from R 2 is hydrogen, alkyl, hydroxyalkyl, haloalkyl, aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, amidoalkyl, alkylamidoalkyl, dialkylamidoalkyl, alkanoylalkyl, azidoalkyl, carbamoylalkyl, alkyl optionally interrupted by a heteroatom; alkenyl, alkenyloxyalkyl; cycloalkylalkyl, heterocycloalkyl; aryl, aralkyl, aralkenyl, heteroarylalkyl, in which aryl is optionally substituted by alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, halo, amino, alkylamino or dialkylamino; aroylalkyl, or heteroaroylalkyl; R 3 and R 4 form a fused 5- to 7-membered saturated carbocyclic ring, optionally substituted by one or more substituents selected from alkyl of 1 to 4 carbon atoms, halo or haloalkyl of 1 to 4 carbon atoms; and DYE is a dye moiety selected from the group consisting of dipyrrometheneboron difluoride dyes, fluorescein dyes, rhodamine dyes, and Texas Red; or a pharmaceutically acceptable acid addition salt thereof.