Targeted isolation of antiviral cinnamoylphloroglucinol-terpene adducts from Cleistocalyx operculatus by building blocks-based molecular networking approach

The building blocks-based molecular network(BBMN)strategy was applied to the phytochemical investigation of Cleistocalyx operculatus,leading to the targeted isolation of eighteen novel cinnamoylphloroglucinol-terpene adducts(CPTAs)with diverse skeleton types(cleistoperones A-R,1-18).Their structures including absolute configurations were determined by extensive spectroscopic methods,quantum chemical calculations,and single-crystal X-ray crystallographic experiments.Cleistoperone A(1),consisting of a cinnamoylphloroglucinol motif and two linear monoterpene moieties,represents an unprecedented macrocyclic CPTA,whose densely functionalized tricyclo[15.3.1.0^(3,8)]heneicosane bridge ring skeleton contains an enolizableβ,β′-triketone system and two different kinds of stereogenic elements(including five point and three planar chiralities).Cleistoperones B and C(2 and 3)are two new skeletal CPTAs with an unusual coupling pattern between the(nor)monoterpene moiety and the cinnamoyl chain of the cinnamoylphloroglucinol unit.Cleistoperone D(4)possesses an unprecedented cage-like 6/6/6/4/6-fused heteropentacyclic scaffold.The plausible biosynthetic pathways for 1-18 were also proposed.Notably,compounds 1,4,7,8,and 18 exhibited significant antiviral activity against respiratory syncytial virus(RSV).The most potent one,cleistoperone A(1)with IC_(50) value of 1.71±0.61μmol/L,could effectively inhibit virus replication via affecting the Akt/mTOR/p70S6K signaling pathway.

Single‐precursor phase‐controlled synthesis of copper selenide nanocrystals and their conversion to amorphous hollow nanostructures

The crystal phases are essential to the physicochemical properties and functionalities of materials.Copper selenide has emerged as an important and appealing semiconductor,which can exist in a variety of polymorphic phases.However,the richness of polymorphs also makes it a challenge to the direct preparation of copper selenide nanocrystals with tunable phases.Herein,two polymorphs,that is,quasitetragonal Cu2−xSe nanocubes and metastable wurtzite Cu2Se nanodisks,are successfully synthesized by using a single precursor,copper(I)selenocyanate(CuSeCN),as the Cu and Se sources.The key to phase modulation is the optimal choice of the ligand in the synthesis.The as‐prepared nanocrystals possess different morphologies and compositions,giving rise to distinct optical properties and electrical conductivities.Interestingly,the copper selenide nanocrystals can provide a platform for the rational construction of two types of amorphous hollow Au─Cu─Se nanostructures by reaction with Au(I)precursor,in which their final shapes are well kept as that of the original nanocrystal templates.This work provides an easy strategy for the phase‐controlled synthesis of copper selenide nanocrystals and enables the design of new materials for broad applications.