Synthesis And Application Of Multi-substituent Pyrrolo[3,4-d] Pyrimidine-5,7-diones And Aryl-substituent Benzyl Acids

Part Ⅰ:Synthesis and fluorescence properties of substituent pyrrolo [3,4-d] pyrimidine-5,7-dionesBackground:Traditional fluorescent compounds when aggregated, can cause fluorescence quenching (aggregation caused quenching, ACQ). ACQ effect limits the application of fluorescent molecules, especially in fluorescent probes, OLED, etc. On the contrary, compounds with AIE (aggregation-induced emission, AIE) properties have weak or none fluorescence in dilute solution, and strong fluorescence when aggregated. In2001, Silole with AIE properties was firstly reported by Tang. They proposed that the mechanism of AIE was due to the restricted intermolecular rotation (RIR) under the state of aggregation. When aggregation between different molecules, the internal rotation of aromatic ring had limited, thus molecules radiation energy transfer reduced. The result was fluorescence intensity enhancement. In recent years, compounds with AIE properties have already successfully applied in ion detection, protein detection, DNA detection and cell image. Our research group previously reported a novel structure of tetrahydro-pyrimidine with strong AIE properties which can be synthesized by one pot multicomponent reaction (MCR). The highest fluorescence quantum yield of these tetrahydropyrimidines can reach93%. At the same time, these compounds had already successfully applied in metal ions detection and surface active agent detection. Applications in protein research are ongoing in our laboratory. Based on the previous studies, we synthesized a novel structure of multi-substituent pyrrolo[3,4-d] pyrimidine-5,7-diones compounds with good AIE properties. In this paper, the synthesis conditions were optimized and a series of analogues were synthesized. The fluorescence properties have been determined.Methods:We synthesized the target compounds7with dimethyl acetylenedicarboxylate (DMAD) as starting material by one-pot MCR. First, synthesis of two-substituted pyrrolo[3,4-d] pyrimidine-5,7-diones compounds by four components reaction. We can obtain the target products, but the yields were low. Under the detection of reaction process, we isolated pyrrole derivatives intermediates (compounds4). Finally, the processes divided into two steps. Firstly we obtained the derivatives of pyrrole (compounds4). The second step, we reacted compounds4with different amine and aldehyde. We studied the influence of catalyst, solvent, temperature, time and the ratio of reactants on this MCR.Three substituted pyrrolo[3,4-d]pyrimidine-5,7-dione were synthesized using intermediates (compounds4), different amine and formaldehyde as reactants.The AIE properties of pyrrolo[3,4-d]pyrimidine-5,7-diones have been tested.The compounds aggregated in a mixed solution of ethanol/water. And the fluorescence intensity changed with the ratio of ethanol/water.9a has good AIE property with the fluorescence quantum yield of37%. Results:(1)11pyrrole derivatives (compounds4) and33pyrrolo[3,4-d] pyrimidine-5,7-diones were obtained.(2) Two substituted pyrrolopyrimidine compounds were synthesized by one-pot3components reaction with intermediate4, formaldehyde and amine as raw materials.26analogues were obtained. Three substituted pyrrolopyrimidine compounds were synthesized by one-pot4components reaction with intermediate4, formaldehyde, amine and benzaldehyde as raw materials.7analogues were obtained.(3) The compounds aggregated in a mixed solution of ethanol/water. And the fluorescence intensity changed with the ratio of ethanol/water.9is has good AIE properties with the fluorescence quantum yield of37%.Conclusions:(1) The yields of26two-substituted compounds are75～91%. The reactions were simple, economic and materials were cheap. It can be concluded that the substituents R1and R2have little impact on this reaction. Both electron-deficient and electron-rich aromatic group in R1gave very good chemical yields.(2) The yields of three-substituted compounds are30～50%. It may be caused by higher steric hinderance effect of phenyl group and lower nucleophilicity. The reaction activity of benzaldehyde was lower than that of formaldehyde.(3) The synthesized compounds have aggregation-induced emission properties (AIE). They aggregated in a mixed solution of ethanol/water. And the fluorescence intensity changed with the ratio of ethanol/water. Part II. Design, synthesis and activity of aryl-substituent benzyl acid targeting HIV gp41Background:There are about700000HIV-infected people in our country, including80000cases of AIDS. According to the WHO statistics, the proportion of HIV infection in our country was very low at present, but the number of infections was the second in Asia and the14th all over the world. The best HIV/AIDS prevention should be the vaccine, but there has no effective HIV vaccine for more than20years. Therefore, the development of safe and effective anti-HIV drugs is current research hotspot.Three types of26kinds of anti-HIV drugs have approved by FDA so far: reverse transcriptase inhibitors, protease inhibitors and HIV entry inhibitors. Two former type of drugs can induce drug resistance easily. The serious side effects to human body generated declining medicine patients. HIV entry inhibitors, although there are only Fuzeon and Maraviroc, are still effective on the tolerance of two former type anti-HIV drugs. It also can form more "cocktail" program for the treatment of HIV. Therefore, the development of HIV entry inhibitors has become the research hotspot.Entry inhibitors prevent HIV fusing with target cells in the early stage. They were considered better application prospect on HIV prevention. The Fuzeon is a36amino acids of peptides derived from gp41. It could hydrolysis easily in the body. Therefore, small molecules of HIV entry inhibitors have been the research hotspot. The small molecule inhibitors targeting HIV gp41were reported. Jiang reported two benzoic acid compounds firstly:NB-2and NB-64. They have good anti-HIV activities to inhibit the formation of gp41six-helix bundle. However, the molecular mass is small and the molecular structure into a medicinal property is poor. They only could be used as lead compounds. The structural modifications also done by scientists were in order to discover new HIV entry inhibitors. The N substituted pyrrole or benzopyrrole as the mother nucleus reported by Teixeira, Liu, Wang etc. The indole rings as the mother nucleus reported by Meanwell and Zhou. They designed and synthesized a series of compounds to inhibit HIV replication in micro mole level. Studies have found that the carboxyl functional group is necessary active group. The results from the stimulation of Docking soft: carboxyl and gp41K574residue formed salt bridge.Methods:To synthesize novel aryl-substituent benzyl acid compounds targeting HIV gp41and characterize their anti-HIV activities. The key intermediates14preparation was based on bromide and borate through palladium catalytic Suzuki-Miyaura coupling reaction. The formation of C-C key combination makes two aromatic rings connection. The reaction needs nitrogen protection because of palladium catalyst. The target compounds16synthesized by Knoevenagel condensation reactions from intermediate14and15. Piperidine was catalyst and ethanol as solvent. The yields were from40%to56%. Twelve analogues were designed and synthesized by Knoevenagel condensation reactions. The inhibitory activities of these compounds on gp41six-helix bundle formation were tested by ELISA and anti-HIV activities were determined by luciferase assay.Results:The structures of the compounds were characterized by NMR and MS spectra. Among the12compounds, five of them (16b,16c,16d,16e, and16g) could inhibit the gp41six-helix bundle formation.7d was the most potent effect.7d could also inhibit the replication of HIV-1SF33strain with an IC5020μmol/L.Conclusions:Therefore, the NB-2and NB-64as the lead compounds, Carboxy-substituted aromatic ring or an aromatic heterocyclic turned out more effective. Activity of these compounds resistance to hiv-1SF33in micromole level. In order to obtain more effective compounds, we will continue to explore more detail of this series compounds structure-activity relationship.