Vinyl substituted radiohalogen conjugates for protein labeling

Vinyl radiohalogenated small molecules as shown in formulas I and II: I II wherein *X is a radiohalogen, C=C is a double bonded set of sp2 hybridized carbon atoms, and substituents R1, R2, and Y are as defined below. R1 and R2 are substituents independently selected from among hydrogen; alkyl or substituted alkyl, provided that any sp2 or sp carbon atom substituted on the alkyl is separated from C=C by at least one fully substituted sp3 carbon atom; aryl or substituted aryl, provided that the aryl is bonded directly to C=C; heteroalkyl, provided, first, that no heteroatom of the heteroalkyl bonds directly to C=C and, second, that any sp2 or sp hybridized carbon bonded to a heteroatom of the heteroalkyl is not bonded directly to or otherwise conjugated with C=C and, third, that where a single sp3 carbon intervenes between C=C and an sp2 or sp carbon bonded to a heteroatom that intervening sp3 carbon must be fully substituted; heteroaryl, provided that a heteroatom of the heteroaryl is not bonded directly with C 50 C; mixed alkylaryl, provided first, that no heteroatom is bonded to C=C and, second that either an aryl moiety of the mixed alkylaryl is directly bonded to C=C or that any aryl moiety is separated from C=C by at least one sp3 carbon atom and, where only one sp3 hybridized carbon atom intervenes between C=C and an aryl moiety, that intervening sp3 carbon must be fully substituted. Y is substituent containing any of the groups described above for R1 and R2, except that Y cannot be hydrogen, and bearing a functional group suitable for binding to protein under conditions that preserve the biological activity of the protein. The compounds of formulas I and II can be coupled to proteins such as monoclonal antibodies ot provide reagents for diagnostic and therapeutic applications. Also metalated precursors of compounds I and II, as well as radiophormaceutical reagent kits containing any of the subject small molecules.