Synthesis And Characterization Of 5-Oxo-Tetra Hydro-4H-Benzo[b]Pyran Derivatives

Recently , Compouds containing Benzo[b]pyran structure is the hotspot of new drugs development, which possess antitumor, choleretic treatment and eliminating urolith, anticoagulation, anti-osteoporosis, anti-inflammatory, anti-fungus, hemangiectasis, reducing blood sugar , antivirus, anti-schistosomiasis, and so on. Now, the anti-osteoporosis drug, anticoagulation drug, anti-inflamatory drug of benzo[b]pyran have been applied to clinical; and drugs of reducing blood sugar, antivirus, anti-schistosomiasis contain Benzo[b]pyran structure.Thus, this paper mainly studies on the synthesis and characterization of 5-oxo-tetrahydro-4H-benzo[b] pyran derivatives.Nowadays, there are few reports on the synthesis of 5-oxo-tetrahydro -4H-benzo[b]pyran derivatives, mainly including cyclization in solid alkali, dehydrolysis with acid anhydride, catalysis by PF3-Et2O in CH3COOH, catalysis by ZnCl2 coupling with the azeotropic water removing. However, these present methods are imperfect for the lower yields, difficulty to separate the products, narrower application range and environment pollution. Thus,these drawbacks seriously affect its industrial production and further study.In this paper, aiming to seek the synthesis method which is environment friendly and easily available in industry with extensive application range, convenient purification way , we have completed synthesis design, synthesis and characterization of seven 5-oxo-5,6,7,8-tetrahydro-4H-benzo[b]pyran derivatives in combination with related literature. The main work in the paper is as follows:1. On the Combination of related literature, we first put forward the synthesis of 5-Oxo-5,6,7,8-tetrahydro-4H-benzo[b]pyran derivatives by Micheal addition-condensation reaction in [bmim][BF4] promoted by InCl3/TMSCl.2. Seven 5-Oxo-5,6,7,8-tetrahydro-4H-benzo[b]pyran derivatives with Non-identical Groups have been synthesized, five of which are new compouds.3. Structure determination of the target compound by IR, 1H NMR, MS and HRMS, which shows that the spectra data is consistent with structure.4. The effect of catalyst amount on yield was investigated. When the molar ratio of reactant to catalyst was 1∶0.2, the yield was 55%.5. Research on recycle of [bmim][BF4] containing InCl3, the cyclic utilization rateis up to 90%; It is obvious that the reaction can give the product with a yield almost as high as that of the first roundactivity after four times of repeated use.6. Taking ethyl acetate-cyclohexane as the solvents of crystallization, results show that high purity and fine crystal shape products can be obtained, abolishing column chromatography which goes against industrialization.In summery, the synthesis method which is environment friendly and easily available in industry with extensive application range and convenient purification way in this paper can be applied in the industrialized production, thus providing a basis for the research and development of the 5-Oxo-5,6,7,8-tetrahydro-4H-benzo[b]pyran drugs.