Two racemic pairs of new stilbenoid dimers,(±)-heterosmilaxones A(1)and B(2),with unique 6/6/6and 6/5/7 tricyclic core systems,respectively,were isolated from the rhizomes of Heterosmilax yunnanensis.Their struct...Two racemic pairs of new stilbenoid dimers,(±)-heterosmilaxones A(1)and B(2),with unique 6/6/6and 6/5/7 tricyclic core systems,respectively,were isolated from the rhizomes of Heterosmilax yunnanensis.Their structures were elucidated through comprehensive spectroscopic analyses,quantum chemical calculations and X-ray diffraction crystallography.Compound(+)-1,initially reported as syagrusin A with a 1,4,4a,9a-tetrahydrofluoren-9-one skeleton,is now revised to a new structure characteristic with a benzo bicyclo[3.3.1]nonene scaffold.And compound 2 bears an unprecedented carbon skeleton with four continuous chiral centers in the central benzo bicyclo[4.2.1]nonene motif.Biogenetically,both 1 and2 were proposed to derive from 3,3',4,5,5'-pentahydroxy stilbene and could be generated through key inverse-electron-demand[4+2]and[5+2]cycloadditions,respectively.Interestingly,both(±)-1 and(±)-2 showed significant inhibition againstα-glucosidase.(±)-1 and its pure enantiomers could modulate protein tyrosine phosphatase-1B(PTP1B)enzyme activities and increased glucose consumption in HepG2 cells in a dose-dependent manner.展开更多
Nineteen preschisanartane-type schinortriterpenoids(SNTs),among which eleven ones were previously undescribed,were isolated from two Schisandra species,S.sphaerandra and S.rubriflora.Their structures were determined u...Nineteen preschisanartane-type schinortriterpenoids(SNTs),among which eleven ones were previously undescribed,were isolated from two Schisandra species,S.sphaerandra and S.rubriflora.Their structures were determined using 1 D and 2 D NMR spectroscopic analyses,NMR data comparison,quantum chemical calculation of NMR parameters,electronic circular dichroism(ECD),X-ray single crystal diffraction,and chemical derivation.Furthermore,structural re-examination of a few previously reported preschisanartane-type SNTs led to the structural revision of preschisanartanin J.Besides,it is suggested that the reported structures of arisanlactone D and schilancidilactone W should be re-checked.Finally,a few isolated SNTs were found to possess neurite outgrowthpromoting activities,and protective activities against neural injuries.展开更多
Two hitherto unknown lanostane-type triterpenoids,namely scillascillol(1)and scillascillone(2),and a hitherto unknown norlanostane-triterpene glycoside,namely scillascilloside B-1(3),were isolated from the ethanol ext...Two hitherto unknown lanostane-type triterpenoids,namely scillascillol(1)and scillascillone(2),and a hitherto unknown norlanostane-triterpene glycoside,namely scillascilloside B-1(3),were isolated from the ethanol extract of the whole plants of Scilla scilloides.Their structures were elucidated on the basis of extensive spectroscopic studies.In addition,the structure of drimiopsin D(6a)has been revised as 2,5-dimethoxy-8-methyl-1,3,6-trihydroxyxanthone(6)by reanalysis of the spectroscopic data.展开更多
The structure factors of any crystal structure can be simulated from its atomic coordinates (and temperature factors) in a SHELXL-97 run on a dummy hkl in which only the scale factor is refined. The squares of the str...The structure factors of any crystal structure can be simulated from its atomic coordinates (and temperature factors) in a SHELXL-97 run on a dummy hkl in which only the scale factor is refined. The squares of the structure factors are retrieved from the fcf, and such simulated data are used in the revision of the space groups of several incorrectly-refined crystal structures. Two cases, a P1 to P1 revision and a chemically-incorrect structure that is refined in a correct space group, are discussed.展开更多
We describe the design and execution of a novel synthetic route to the tricyclic core of haliclonin A,a tetracyclic marine natural product.The approach features Bachi＇s thiol-medicated free radical cyclization of alk...We describe the design and execution of a novel synthetic route to the tricyclic core of haliclonin A,a tetracyclic marine natural product.The approach features Bachi＇s thiol-medicated free radical cyclization of alkenyl isocyanide to build the bridged ring system,and ring-closing metathesis（RCM） reaction to form the macrocycle.Execution of the synthetic plan ultimately resulted in a diazatricyclic compound.By means of 2D NMR techniques,the structure of this compound was revealed to an unexpected product 8.Analysis of the synthetic pathways allowed concluding that the unexpected product is a result of an ＂unexpected＂ migration of olefinic bond during dioxolanation of the 2-cyclohexenone derivative 7.This investigation also resulted in a concise construction of the functionalized hexahydro-1H-isoindole-1,5（4H）-dione 12 and the macrocyclic tricyclic ring system 8.展开更多
Five hitherto unknown isoflavonoids,namely erythrinins D-H(1-5),were isolated from the ethanol extract of Erythrina arborescens.Their structures were elucidated on the basis of extensive spectroscopic studies.In addit...Five hitherto unknown isoflavonoids,namely erythrinins D-H(1-5),were isolated from the ethanol extract of Erythrina arborescens.Their structures were elucidated on the basis of extensive spectroscopic studies.In addition,the structure of anagyroidisoflavone A(6a)has been revised as 1″-O-methylerythrinin F(6)by re-analysis of the original spectroscopic data.展开更多
Four new norditerpenoid heterodimers with different dimerization patterns-namely,trigofragiloids A-C(denoted as compounds 1-3)and(+)-and(-)-trigofragiloid D(compound 4)-and three new phenanthrenone norditerpenoids-nam...Four new norditerpenoid heterodimers with different dimerization patterns-namely,trigofragiloids A-C(denoted as compounds 1-3)and(+)-and(-)-trigofragiloid D(compound 4)-and three new phenanthrenone norditerpenoids-namely,trigofragiloids E-G(compounds 5-7)-were isolated from Trigonostemon fragilis.Compounds 1 and 2 feature a novel heterodimeric carbon skeleton formed by the conjugation of a tetra-norditerpenoid and an ennea-norditerpenoid;they have been identified as class 2 atropisomers by means of quantum chemical calculations.Compound 3 is an unprecedented phenylpropanoid-norditerpenoid adduct with a new dimerization pattern.Compounds(+)-and(-)-4 are the first example of S-shaped 1,4-dioxane-fused norditerpenoid dimers.Inspired by the structure elucidation of compound 4,two co-occurring analogues,actephilol A and epiactephilol A,were structurally revised as a pair of geometrical isomers and were identified as two pairs of enantiomers,(+)-and(-)-8 and(+)-and(-)-9,respectively.Their structures were characterized using a combined method.Notably,compound 7 exhibits remarkable adenosine triphosphate-citrate lyase(ACLY)inhibition with a halfmaximal inhibition concentration(IC50)value of(0.46±0.11)lmol·L^(-1),as active as the positive control BMS-303141,and a molecular docking study offers deep insight into the interaction between compound 7 and ACLY.展开更多
Four hitherto unknown aristolane-type sesquiterpenes,including one novel 8,9-secoaristolane,namely secoaristolenedioic acid(1),two aristolone derivatives,namely 1α,2β-dihydroxyaristolone(2),9-epidebilon(3),and one r...Four hitherto unknown aristolane-type sesquiterpenes,including one novel 8,9-secoaristolane,namely secoaristolenedioic acid(1),two aristolone derivatives,namely 1α,2β-dihydroxyaristolone(2),9-epidebilon(3),and one rare aristolane-chalcone hybrid,namely 3′-hydroxynardoaristolone A(4)were isolated from the ethanol extract of the roots and rhizomes of Nardostachys chinensis.Their structures were elucidated on the basis of extensive spectroscopic analysis.In addition,the structure of aristolanhydride,recently isolated from the same species,was corrected by reanalysis of the published NMR data.展开更多
The enantioselective total synthesis of the putative structure of versiquinazoline H and three diastereomers has been achieved,which allowed the revision of the stereochemistry of this natural product.This six-step to...The enantioselective total synthesis of the putative structure of versiquinazoline H and three diastereomers has been achieved,which allowed the revision of the stereochemistry of this natural product.This six-step total synthesis relied on the evolution of the strategy that we previously developed,which features a DMDO-triggered tandem reaction.The modification of the lactamization step resulted in a significant improvement of yield that ensured the efficient total synthesis.展开更多
A scale-up fermentation of the fungus Boreostereum vibrans facilitated the isolation of six new vibralactone biogenesis-associated analogues,namely vibralactamide A(1),vibralactone T(2),13-O-lactyl vibralactone(3),10-...A scale-up fermentation of the fungus Boreostereum vibrans facilitated the isolation of six new vibralactone biogenesis-associated analogues,namely vibralactamide A(1),vibralactone T(2),13-O-lactyl vibralactone(3),10-O-acetyl vibralactone G(4),(11R,12R)-and(11S,12R)-vibradiol(5,6).Their structures were established via extensive spectroscopic analyses,specific optical rotation comparison,and Snatzke’s method.The biosynthetic pathway for vibralactamide A was postulated.The absolute configuration of vibralactone B was revised by single crystal X-ray diffraction analysis.This work puts the divergent vibralactone biosynthesis pathway one step further and expands the structural diversity of vibralactone-associated compounds.展开更多
Trichosanthin is a type I ribosome inactivating protein,with a variety of medical functionincluding anti-virus. The primary and three-dimensional structure of trichosanthin were reported previously,which contained 234...Trichosanthin is a type I ribosome inactivating protein,with a variety of medical functionincluding anti-virus. The primary and three-dimensional structure of trichosanthin were reported previously,which contained 234 amino acid residues. In this communication we present the resultsabout the revision of the three-dimensional structure based on a solvent flattened map accor-ding to the primary structure revised by Collins et al. and checked by a Chinese group,Which will be described in detail elsewhere.展开更多
基金financially supported by the CAMS Innovation Fund for Medical Sciences(CIFMS,No.2021-I2M-1-028)。
文摘Two racemic pairs of new stilbenoid dimers,(±)-heterosmilaxones A(1)and B(2),with unique 6/6/6and 6/5/7 tricyclic core systems,respectively,were isolated from the rhizomes of Heterosmilax yunnanensis.Their structures were elucidated through comprehensive spectroscopic analyses,quantum chemical calculations and X-ray diffraction crystallography.Compound(+)-1,initially reported as syagrusin A with a 1,4,4a,9a-tetrahydrofluoren-9-one skeleton,is now revised to a new structure characteristic with a benzo bicyclo[3.3.1]nonene scaffold.And compound 2 bears an unprecedented carbon skeleton with four continuous chiral centers in the central benzo bicyclo[4.2.1]nonene motif.Biogenetically,both 1 and2 were proposed to derive from 3,3',4,5,5'-pentahydroxy stilbene and could be generated through key inverse-electron-demand[4+2]and[5+2]cycloadditions,respectively.Interestingly,both(±)-1 and(±)-2 showed significant inhibition againstα-glucosidase.(±)-1 and its pure enantiomers could modulate protein tyrosine phosphatase-1B(PTP1B)enzyme activities and increased glucose consumption in HepG2 cells in a dose-dependent manner.
基金supported by the National Natural Science Foundation of China(No.81903520)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(No.2019QZKK0502)
文摘Nineteen preschisanartane-type schinortriterpenoids(SNTs),among which eleven ones were previously undescribed,were isolated from two Schisandra species,S.sphaerandra and S.rubriflora.Their structures were determined using 1 D and 2 D NMR spectroscopic analyses,NMR data comparison,quantum chemical calculation of NMR parameters,electronic circular dichroism(ECD),X-ray single crystal diffraction,and chemical derivation.Furthermore,structural re-examination of a few previously reported preschisanartane-type SNTs led to the structural revision of preschisanartanin J.Besides,it is suggested that the reported structures of arisanlactone D and schilancidilactone W should be re-checked.Finally,a few isolated SNTs were found to possess neurite outgrowthpromoting activities,and protective activities against neural injuries.
基金This work was financially supported by"Largescale Compound Library"project of National Development and Reform Commission of China.
文摘Two hitherto unknown lanostane-type triterpenoids,namely scillascillol(1)and scillascillone(2),and a hitherto unknown norlanostane-triterpene glycoside,namely scillascilloside B-1(3),were isolated from the ethanol extract of the whole plants of Scilla scilloides.Their structures were elucidated on the basis of extensive spectroscopic studies.In addition,the structure of drimiopsin D(6a)has been revised as 2,5-dimethoxy-8-methyl-1,3,6-trihydroxyxanthone(6)by reanalysis of the spectroscopic data.
文摘The structure factors of any crystal structure can be simulated from its atomic coordinates (and temperature factors) in a SHELXL-97 run on a dummy hkl in which only the scale factor is refined. The squares of the structure factors are retrieved from the fcf, and such simulated data are used in the revision of the space groups of several incorrectly-refined crystal structures. Two cases, a P1 to P1 revision and a chemically-incorrect structure that is refined in a correct space group, are discussed.
基金the National Natural Science Foundation of China(No.21472153)the National Basic Research Program(973 Program)of China(No.2010CB833200)+1 种基金the SKL of Xiamen University(No.201509)the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education,China,for financial support
文摘We describe the design and execution of a novel synthetic route to the tricyclic core of haliclonin A,a tetracyclic marine natural product.The approach features Bachi＇s thiol-medicated free radical cyclization of alkenyl isocyanide to build the bridged ring system,and ring-closing metathesis（RCM） reaction to form the macrocycle.Execution of the synthetic plan ultimately resulted in a diazatricyclic compound.By means of 2D NMR techniques,the structure of this compound was revealed to an unexpected product 8.Analysis of the synthetic pathways allowed concluding that the unexpected product is a result of an ＂unexpected＂ migration of olefinic bond during dioxolanation of the 2-cyclohexenone derivative 7.This investigation also resulted in a concise construction of the functionalized hexahydro-1H-isoindole-1,5（4H）-dione 12 and the macrocyclic tricyclic ring system 8.
基金This work was financially supported by the"Large-scale Compound Library"project of the National Development and Reform Commission of China,the National Basic Research Program of China(973 Program)2009CB522300the"Western Light"talents training program of Chinese Academy of Sciences.
文摘Five hitherto unknown isoflavonoids,namely erythrinins D-H(1-5),were isolated from the ethanol extract of Erythrina arborescens.Their structures were elucidated on the basis of extensive spectroscopic studies.In addition,the structure of anagyroidisoflavone A(6a)has been revised as 1″-O-methylerythrinin F(6)by re-analysis of the original spectroscopic data.
基金support from the National Natural Science Foundation of China(22237007 and 22177122)the Biological Resources Program of Chinese Academy of Sciences(CAS)(KFJ-BRP-008-001)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2022282)is gratefully acknowledged.We thank Prof.Shi-Man Huang,Department of Biology,Hainan University,China,for the identification of the plant material.
文摘Four new norditerpenoid heterodimers with different dimerization patterns-namely,trigofragiloids A-C(denoted as compounds 1-3)and(+)-and(-)-trigofragiloid D(compound 4)-and three new phenanthrenone norditerpenoids-namely,trigofragiloids E-G(compounds 5-7)-were isolated from Trigonostemon fragilis.Compounds 1 and 2 feature a novel heterodimeric carbon skeleton formed by the conjugation of a tetra-norditerpenoid and an ennea-norditerpenoid;they have been identified as class 2 atropisomers by means of quantum chemical calculations.Compound 3 is an unprecedented phenylpropanoid-norditerpenoid adduct with a new dimerization pattern.Compounds(+)-and(-)-4 are the first example of S-shaped 1,4-dioxane-fused norditerpenoid dimers.Inspired by the structure elucidation of compound 4,two co-occurring analogues,actephilol A and epiactephilol A,were structurally revised as a pair of geometrical isomers and were identified as two pairs of enantiomers,(+)-and(-)-8 and(+)-and(-)-9,respectively.Their structures were characterized using a combined method.Notably,compound 7 exhibits remarkable adenosine triphosphate-citrate lyase(ACLY)inhibition with a halfmaximal inhibition concentration(IC50)value of(0.46±0.11)lmol·L^(-1),as active as the positive control BMS-303141,and a molecular docking study offers deep insight into the interaction between compound 7 and ACLY.
基金supported by the“Large-scale Compound Library”project of National Development and Reform Commission of China.
文摘Four hitherto unknown aristolane-type sesquiterpenes,including one novel 8,9-secoaristolane,namely secoaristolenedioic acid(1),two aristolone derivatives,namely 1α,2β-dihydroxyaristolone(2),9-epidebilon(3),and one rare aristolane-chalcone hybrid,namely 3′-hydroxynardoaristolone A(4)were isolated from the ethanol extract of the roots and rhizomes of Nardostachys chinensis.Their structures were elucidated on the basis of extensive spectroscopic analysis.In addition,the structure of aristolanhydride,recently isolated from the same species,was corrected by reanalysis of the published NMR data.
基金financial support from the National Natural Science Foundation of China (Nos.21672176 and 21332007)the National Key R&D Program of China (No. 2017YFA0207302)
文摘The enantioselective total synthesis of the putative structure of versiquinazoline H and three diastereomers has been achieved,which allowed the revision of the stereochemistry of this natural product.This six-step total synthesis relied on the evolution of the strategy that we previously developed,which features a DMDO-triggered tandem reaction.The modification of the lactamization step resulted in a significant improvement of yield that ensured the efficient total synthesis.
基金supported by National Natural Science Foundation of China(No.81561148013).
文摘A scale-up fermentation of the fungus Boreostereum vibrans facilitated the isolation of six new vibralactone biogenesis-associated analogues,namely vibralactamide A(1),vibralactone T(2),13-O-lactyl vibralactone(3),10-O-acetyl vibralactone G(4),(11R,12R)-and(11S,12R)-vibradiol(5,6).Their structures were established via extensive spectroscopic analyses,specific optical rotation comparison,and Snatzke’s method.The biosynthetic pathway for vibralactamide A was postulated.The absolute configuration of vibralactone B was revised by single crystal X-ray diffraction analysis.This work puts the divergent vibralactone biosynthesis pathway one step further and expands the structural diversity of vibralactone-associated compounds.
基金Project supported by the grants from the Chinese Academy of Sciences from the High Technology Development Program of China
文摘Trichosanthin is a type I ribosome inactivating protein,with a variety of medical functionincluding anti-virus. The primary and three-dimensional structure of trichosanthin were reported previously,which contained 234 amino acid residues. In this communication we present the resultsabout the revision of the three-dimensional structure based on a solvent flattened map accor-ding to the primary structure revised by Collins et al. and checked by a Chinese group,Which will be described in detail elsewhere.
