Abstract:
Nitric oxide (NO) is an important biological signaling molecule. Diaminofluorescein (DAF 2) is one of the most effective NO probes. Linking DAF 2 with other functionalities through tagging technique can greatly enhance its targeting effect and spatial sensitivity in detection of NO in vivo. In this work, ortho aminobenzene is chosen as the model compound of DAF 2 to study the synthetic strategy of mono substitution. Diacetyl ester of DAF 2 is used to verify the optimized reaction condition. High performance liquid chromatography (HPLC) and liquid chromatography mass spectroscopy (LC MS) were employed to determine the composition and content of substituted product. Results show that bromoacetyl bromide is the best linker between DAF 2 and HaloTag. Mono HaloTag substituted DAF 2 is obtained with a yield of 34.8%. This study paves a way for development and application of mono substituted ortho diamino type fluorescence probes for NO.