Ionic liquid promoted and mediated green preparation ofarylbispyranylmethane and pyran derivatives and their hybridwith a pyrimidine nucleoside

摘要

The utilisation of an ionic liquid—[bmim][BF_4] as both reaction medium and promoter for the reaction betweenaldehyde and 4-hydroxy-6-methylpyran-2-one is described. Without any added catalyst, this reaction was realisedefficiently to give arylbispyranylmethane derivatives in high yields. Alternatively, when this reaction was carriedout in the presence of acetic anhydride, fused pyran derivatives were obtained. These two novel procedures haveadvantages such as an environmentally benign nature, high efficiency, simple operation process and mild reactionconditions. As an application, these procedures were used in the preparation of novel 5-substituted pyrimidinenucleoside derivatives with potential antiviral activities.