First Total Synthesis of Four Benzodioxane Neolignans

Four 1,4-benzodioxane neolignans were first synthesized from pyrogallol, in which the Claisen rearrangement was used to afford three important C-6-C-3 units.

A Novel Stereoselective Synthesis of 8-O-4' Neolignans

1-(4-hydroxy-3-methoxyphenyl)-2-(4-formyl-2-methoxyphenoxy)-propane-1,3-diol. A 8-O-4' neolignan, has been stereoselectively synthesized in eight steps from ferulic acid, and the directly cis opening of epoxide in eposidation and Mitsunobu reaction were used ingeniously as two key steps with high stereoselectively.

TWO NEW NEOLIGNANS FROM MESSERSCHMIDIA SIBIRICA L.SSP.

From the aerial parts of Messerschmidia sibirica L.ssp.,two new neolignans were isolated and elucidated as messerschmidin and its acetate.

NEOLIGNANS FROM PIPER KADSURA(Ⅱ)

Two new bicyclo[3,2,1]octanoid neolignans,named as kadsurenin I and kadsurenin J were isolated from Piper kadsura(Choiey)Ohwi.Based on the spectros- copic analysis(UV,IR,MS and NMR)and chemical derivatization,their structures were established as 7R,8R,1'R,2'S,3'R-Δ~s'-3,4,5'-trimethoxy-2'-hydroxy-1',2',3',4'- tetrahydro-4'-oxo-7.3',8.1'-neolignan and 7R,8R,1'R,2'S,3'R-Δ~s'-3,4,5'-trimethoxy -2'-acetoxy-1',2',3',4'-tetrabydro-4'-oxo-7.3',8.1'-neolignan respectively.

Two new neolignans from Manglietia insignis

Two new neolignans,manneoinsigins A(1)and B(2),together with four known lignans,were isolated from the leaves and stems of Manglietia insignis.The new compounds were established on the basis of extensive spectroscopic analyses.All compounds except 2 were tested for their cytotoxic activity.Compound 3 showed weak cytotoxic activity against the HL-60 human tumor cell line with the IC50 value of 23.5μM.

New oligomeric neolignans from the leaves of Magnolia officinalis var. biloba

Six new oligomeric neolignans including two trimeric neolignans(1 and 2)and four dimeric neolignans(3–6)were isolated from the leaves of Magnolia officinalis var.biloba.Their structures were determined based on HR-ESIMS and NMR data,as well as electronic circular dichroism(ECD)calculations.Compound 1 is formed from two obovatol moieties directly linked to an aromatic ring of the remaining obovatol moiety,which is an unprecedented type of linkage between monomers.All isolates were assessed for their inhibitory effects on NO production in LPS-stimulated RAW 264.7 macrophage cells.Compounds 1 and 3 showed significantly inhibitory activities with IC50 values of 6.04 and 3.26μmol·L^(−1),respectively.

Bioactive neolignans and lignans from the roots of Paeonia lactiflora

Two new neolignans and one new lignan(1-3)were obtained from the roots of Paeonia lactiflora.Their structures were unambiguously elucidated based on extensive spectroscopic analysis,single-crystal X-ray crystallography,and the calculated and experimental electronic circular dichroism(ECD)spectra.Compound 1 was a racemic mixture and successfully resolved into the anticipated enantiomers via chiral-phase HPLC.Compound 3 demonstrated moderate inhibitory activity against human carboxylesterase 2A1(hCES2Al)with an IC_(50) value of 7.28±0.94 μmol·L^(-1).

Two new neolignans from Gymnotheca involucrata

Two new biphenyl butyl neolignan derivatives,named gymnothebutyllignans A（1） and B（2）,were isolated from the whole parts of endemic medicinal plant of Gymnotheca involucrata（Saururaceae）.The structures of the new compounds were elucidated by extensive NMR and MS data,and the absolutely configuration of compound 1 was confirmed by X-ray crystal diffraction analysis.

First Enantioselective Synthesis of Isoamericanol A and Isoamericanin A

The first enantioselective synthesis approach to two chiral 1,4-benzodioxane neolignans isoamericanol A and isoamericanin A was reported.

Synthesis of 2-aryl-5-alkyl-7-methoxylbenzo[b]furan derivatives

A series of 2-aryl-5-alkyl-7-methoxylbenzo[b]furan derivatives have been synthesized by utilizing the coupling of methyl 3- methoxy-4hydroxy-5-bromocinnamate with cuprous phenylacetylide as the key step. The structures of the new compounds were confirmed by 1H NMR, IR and MS. The structure of compound 14 was further confirmed by single crystal X-ray. Compound 17 showed cytotoxic activity against human lung carcinoma A549.

Synthesis of (±)-Demethylnitidanin, Herpetol and Salvinal as well as Their Glycosyl Derivatives

Three neolignans, （±）-demethylnitidanin（1）, herpetol（2） and salvinal（3） were synthesized from methyl 4,5-dihydroxy-3-methoxy cinnamate or methyl 4-hydroxy-3-methoxy cinnamate with Ag2O-catalyzed biomimetic oxidative coupling as the key step of the synthetic route. Five novel benzofuran neolignan-4＇-O-β-D-glycosides（4―8） were achieved by the glycosylation reactions of benzofuran neolignans 2, 3 and 15. The structures of all the compounds synthesized were determined by MS, 1H NMR and IR spectra. （±）-Demethylnitidanin（1） and herpetol（2） were the first synthesized and the synthesis of salvinal（3） was efficiently improved by the new synthetic routes.

Symplocosionosides A-C, Three Megastigmane Glycosides, a Neolignan Glucoside, and Symplocosins A and B, Two Triterpene Glycosyl Esters from the Leaves of <i>Symplocos cochinchinensis</i>var. <i>Philippinensis</i>

From the 1-BuOH-soluble fraction of a MeOH extract of the leaves of Symplocos cochinchinensis var. philippinensis, 12 compounds were isolated. Spectroscopic analyses of compounds 1 - 3 established their structures to be megastig-mane glycosides, named symplocosionosides A-C. The absolute structure of 1 was determined by the modified Mosher’s method. Compound 4 was found to be a neolignan glucoside and named symplocosneolignan. The structures of com-pounds 5 and 6, named symplocosins A and B, were elucidated to be the saponins of hederagenin sugar esters. The structures of the remaining known compounds (7 - 12) were identified by comparison of spectroscopic data with those reported in the literature.

A NOVEL NEOLIGNAN, BIONDININ A, FROM MAGNOLIA BIONDII PAMP

A novel neolignan, biondinin A, was isolated from the flower buds of Magnolia biondii Pamp. The structure was established as 3,3',4'- trimethoxy-4,9'-dihydroxy-6.8',9-O-7'-neolignan. It is the first reported neolignan possessing the skeleton of benzo-oxa-cyclooctane.

Neolignan glycoside from Angelica dahurica

A new neolignan glycoside, 4-O-β-d-glucopyranosyl-9-O-β-d-glucopyranosyl-(7R,8S)-dehydrodiconiferyl alcohol was isolated from the fresh roots of Angelica dahurica. The structure of the new compound was elucidated on the basis of spectral analysis.

Novel Neolignan from Penthorum chinense

A new neolignan （7＇E）-2＇,4,8-trihydroxy-3-methoxy-2,4＇-epoxy-8,5＇-neolign-7＇-en-7-one （1） was isolated from the whole plants of Penthorum chinense Pursh, along with Iupeol （2）, betulinic acid （3）, glyceryl monopalmitate （4）, β-sitosterol （5）, palmitic acid （5）, ursolic acid （7）, 2β,3β,23-trihydroxy-urs-12-ene-28-oic acid （8）, glyceryl monolaurate （9）, scopoletin （10）, （-）syringaresinol （11）, 9,9＇-O-diferuIoyl-（-）-secoisolariciresionl （12）, pinocembrin （13）, apigenin （14）, kaempferol （15）, Iuteolin （16）, β-daucosterol （17）, quercetin （18）, 1-O-（β-D-glucopyranosyl）-（2S, 2＇R, 3R,4E,8E）-2-（2＇-hydroxyhexadecanoy- lamino）-4,8-octdecadiene-1,3-diol （19）, gallic acid （20）, pinocembrin-7-O-β-D-glucoside （21）, and quercetin-3-O-β-D- glucoside （22）. The structures of these compounds were elucidated on the basis of chemical and spectral evidence.

Codonopiloneolignanin A, a polycyclic neolignan with a new carbon skeleton from the roots of Codonopsis pilosula

A neolignan codonopiloneolignanin A（1） with a novel 2,9：20,9：7,70-tricyclo-8,90-neolignane skeleton was isolated from an aqueous extract of the Codonopsis pilosula roots. Its structure including the absolute configuration was elucidated by extensive spectroscopic analysis, including 2D NMR and electronic circular dichroism calculation. The proposed biosynthetic pathway of compound 1 is also discussed.

(+)-/(-)-Angelignanine,a pair of neolignan enantiomers with an unprecedented carbon skeleton from an aqueous extract of the Angelica sinensis root head

A pair of neolig nan enan tiomers with an unprecedented carb on skelet on,(+)-/(-)-angeligna nine[(+)-/(-)-1].was isolated as minor components of an aqueous extract of the Angelica sinensis root heads(guitou).Their structures were determined by spectroscopic data analysis and the absolute configurations were assigned by the circular dichroism(CD)exciton chirality method as well as electronic CD quantum calculations.The enantiomers represent the first 2,7/-cyclo-8,9z-neolignans,of which biosynthetic pathways originating from precursors ferulic acid and coniferyl alcohol is proposed.In an in vivo test,both the enantiomers showed significant hypnotic effects at a dose of 10 mg/kg(i.g.).

8-O-4’ Neolignan glycosides from the aerial parts of Matteuccia struthiopteris

Two new 8-O-4＇ neolignan glycosides, named matteustruthiosides A（1） and B（2） were isolated from the aerial parts of Matteuccia struthiopteris. Their chemical structures were characterized on the basis of various spectroscopic techniques. The absolute configurations of them were determined by experimental circular dichroism（CD） spectra. Compounds 1 and 2 were inactive against influenza A（H1N1） virus in vitro.