First Synthesis of Bioactive Diphyllin Glycosides Isolated from Justicia patentiflor Hemsl

The syntheses of three naturally occurring diphyllin glycosides have been achieved. 7-O-β-D-Quinovopyranosyl- diphyllin (patentiflorin A) and 7-O-β-L-fucopyranosyldiphyllin (patentiflorin B) were synthesized by the glycosylation of diphyllin with peracetylglycosyl bromides under phase transfer catalysis (PTC) conditions. 4"-O-Acetyl-7-O-β-L-fucopyranosyldiphyllin (4"-O-acetyl patentiflorin B) was obtained from patentiflorin B on an orthoesterification-orthoester rearrangement approach. Their ¹H NMR, ¹³C NMR and HRMS signals are all consistent with those reported for the natural product.