Study On The Synthesis Of Azaheterocyclic Phosphonates And Benzimidazoles Catalyzed By Lanthanide Chlorides

The reactions towards synthesis of novel azaheterocyclic phosphonates and benzimidazoles using lanthanide chlorides as catalyst were studied in this thesis:1. The one-pot reaction of o-phenylenediamines,β-diketones with phosphites catalyzed by ytterbium chlorides (YbCl3) was developed to afford seven membered azaheterocyclic phosphonates efficiently and directly. The reaction was carried out under mild conditions giving 1,5-benzodiazepine-2-ylphosphonate in moderate yields. The effects of molar ratios of substrates and reaction conditions on the activity and selectivity of the present reaction was studied, and the mechanism was also proposed.2. The condensation reaction of o-phenylenediamine withβ-ketoesters via ytterbium chlorides catalyst was studied, which provided benzimidazoles in good to excellent yields under mild conditions. Some functionalized benzimidazoles can also be synthesized conveniently by this method. YbCl3 was found to be water-tolerant and could be recovered and reused.