Synthesis and optical characteristics of near infrared-Ⅱ fluorescent molecule CH1055 / 国际药学研究杂志

ABSTRACT

Objective To optimize the synthetic method for the fluorescent molecule CH1055 and perform a preliminary study on its water solubility and optical properties. Methods Starting from triphenylamine and benzothiadiazole, the desired products were synthesized via a series of reactions, such as Vilsmeier-Haack reaction, acylation, catalytic hydrogenation, bromination, condensation, silylation protection, Suzuki coupling, nitrification and reduction. The structures of the intermediates and targeted compound were confirmed by MS and1 H NMR. At the same time, the key reaction steps were optimized, and the solubility and optical properties of CH1055 were investigated both in vitro and in vivo. Results After improvement of the synthetic method, the total yield increased from 9.13％ in the literature to 12.1％ in the present study. The PEGylated product improved water solubility by about 300 times. At the wavelength of 750 nm long excitation light, CH1055 had better imaging characteristics than the traditional Cy5.5. Conclusion The present method for the CH1055 synthesis has appeared to be cheaper in cost, easy to operate, and higher in yield. After PEGylation modification, the water solubility of the target compound was greatly improved, which was highly advantageous to the development of a water-soluble NIR-Ⅱ fluorescent molecule. CH1055 showed excellent imaging properties in the long wavelength range, which implicated a new potential application of the fluorescent molecule.