Benzocyanine compounds
Compounds useful as labels with properties comparable to known fluorescent compounds. The compounds are conjugated to proteins and nucleic acids for biological imaging and analysis. Synthesis of the compounds, formation and use of the conjugated compounds, and specific non-limiting examples of each are provided.
1. A compound of general formula IIa
or general formula IIb
where
each of R 1 , R 2 , R 5 , and R 6 is the same or different and is selected from the group consisting of an aliphatic, heteroaliphatic, sulfoalkyl, and heteroaliphatic with terminal SO 3 ;
each of R 7 , R 8 , R 11 , R 12 , R 13 , and R 14 is the same or different and is selected from the group consisting of H, and SO 3 wherein at least one of R 7 , R 8 , R 11 , R 12 , R 13 and R 14 is SO 3 ;
X is selected from the group consisting of —OH, —SH, —NH 2 , —NH—NH 2 , —F, —Cl, —Br, I, —NHS (hydroxysuccinimidyl/sulfosuccinimidyl), —O-TFP (2,3,5,6-tetrafluorophenoxy), —O-STP (4-sulfo-2,3,5,6-tetrafluorophenoxy), —O-benzotriazole, -benzotriazole, —NR-L-OH, —NR-L-O-phosphoramidite, —NR-L-SH, —NR-L-NH 2 , —NR-L-NH—NH 2 , —NR-L-CO 2 H, —NR-L-CO—NHS, —NR-L-CO-STP, —NR-L-CO-TFP, —NR-L-CO-benzotriazole, —NR-L-CHO, —NR-L-maleimide, and —NR-L-NH—CO—CH2-I, where R is —H or an aliphatic or heteroaliphatic group;
L is selected from the group consisting of a divalent linear (—(CH 2 ) t —, t=0 to 15), crossed, or cyclic alkyl group optionally substituted by at least one oxygen atom and/or sulfur atom;
Kat is a number of Na + , K + , Ca 2+ , ammonia, or other cation(s) needed to compensate the negative charge brought by the cyanine;
m is an integer from 0 to 5 inclusive; o is an integer from 0 to 12 inclusive; and n is an integer from 1 to 3 inclusive; and Z is a CH 3 group.
2. The compound of claim 1 wherein each of R13 and R14 is sulfo.
3. The compound of claim 1 wherein each of R7, R8, R11, and R12 is sulfo.