| The main purpose of this paper is to synthesize fluoropyridine boric acid compounds.This paper select the premise of halogen that don't participate in the reaction,the aromatic ring C-H key boron chemical reaction(i.e to generate the C-B key),take the iridium catalytic method and amino lithium reagent method as the main synthetic methods mainly,and iridium catalytic method use the method of"one pot stewed"feeding,simple operation,short reaction time,simple post-processing,atom economy,environmental pollution is small,small energy consumption.Lithium method of amino reagent is a site supplement for the synthesis of boric acid(ester)catalyzed by iridium.Its basic operation is similar to which of the butyl lithium method,also its relative advantages are non-halogen participation and atomic economy.Compared with the butyl lithium method,the generation of butyl boric acid,a by-product,is easy to be processed relstively.Experiment on boron source,study of the factors such as temperature,catalyst inventory,found iridium catalytic conditions bottom allied boron frequency that alcohol ester ratio pinacol borane reaction yield about 40%higher on average,the temperature range is in 25-70?,the solvent in a polar aprotic solvent likely n-hexane and n-heptane is optimal,catalyst inventory is between 0.1-0.5%,ligand inventory is between 0.2-1%,average yield of target product is above 80%.Commissioned by jiangsu aikang biomedical research and development co.LTD.,20 kinds of fluoropyridine boric acid(esters)were synthesized,among which 15 were not reported.There were 5 target compounds reported that is needed process improvement in the literature,and their structures were confirmed by~1H NMR and HRMS.The purpose of this paper is to synthesize the target product with high yield and high purity,and to discuss the site effect of different sites of fluoropyridine to produce boric acid(ester)and the significant influence of reaction conditions on process optimization. |
PDF Full Text Request