Synthesis And Characterization Of Intermediates Of New Tumor Targeted Amphiphilic MRI Contrast Agent

Because of its non-invasive, high resolution and good flexibility, MRI has become the most widely used clinical diagnostic imaging technology. With the promotion of MRI, the contrast agent to improve the imaging contrast ratio becomes very important. In this thesis, current research progress of several major T1 MRI contrast agents were introduced (such as enzyme-sensitive contrast agents, metal ions sensitive agents, pH-sensitive contrast agents, cell penetrating and targeting MRI contrast agents, as well as contrast agents with multi hydration number).Integrinαvβ3, which is the receptor protein of RGD peptide, is highly expressed on tumor blood vessls, which made the RGD peptide becomes a novel tumor tageting reagent. It is meaningful work for tumor imaging and cancer treatment that connecting the paramagnetic unit with RGD peptide (and moderate modification) to get a new amphiphilic and tumor targeting MRI comtrast agent. In this thesis, we focused on the synthesis of RGD peptide based amphiphilic MRI congtrast agents for tumor targeting. The main contents are shown as follows:1) An important MRI contrast agent intermediate of DTPA, 1,1,7,7– (tert-butoxycarbonylmethyl) -4- carboxymethyl -1,4,7 - triazine heptane wes synthesised by new designed synthetic route with total yield of 53.9%, This compound has a single actived carboxyl group. Its chemical structure was characterized by spectroscopy method.2) 1,4,7-tritert-butoxycarbonylmethyl-1,4,7,10-tetraazacyclododecane -10-acetic acid, which has a unique carboxyl reaction point, was synthesized. This compound plays an important role in the synthesis of non-ionic contrast agent.3) Two contrast agent ligands were designed, and their prophase synthetic work was finished. These ligands are compose of RGD peptide and long-chain palmitic acid. If coordinated with Gd3+, the complex were expected to be an new amphiphilic and tumor targeted MRI contrast agent.