Two new ceramides from <Emphasis Type="Italic">Zephyranthes candida</Emphasis>

Two new ceramides were isolated from the bulbs of Zephyranthes candida. Their structures were established as (2S,3S,4R,13E)-1,3,4-trihydroxy-2-[(2′R)-2′-hydroxytetracosanoylamino]-13-octadecene, named zephyranamide A (1) and (2S,3S,4R)-1,3,4-trihydroxy-2-octacosanoylaminohexadecene, named zephyranamide B (2). The structures of the new compounds were elucidated by spectral techniques including ¹H NMR, ¹³C NMR, as well as HSQC, HMBC, DEPT, and COSY.     

Isolation,structural determination and cytotoxic activity of two new ceramides from the root of <Emphasis Type="Italic">Isatis indigotica</Emphasis>

Two new ceramides were isolated from the 95% EtOH extract of traditional Chinese medicinal plant Isatis indigotica. Their structures were elucidated as 1-O-β-D-glucopyranosyl-(2S, 3R)-N-(2′-hydroxype-ntacosanoyl)-octadeca-11E-sphingenine (1) and 1-O-β-D-glucopyranosyl-(2S,3R)-N-(2′-hydroxyhe xacosanoyl)-octadeca-11E-sphingenine (2) on the basis of spectroscopic data. Their cytotoxic effects were evaluated by using MTT method.     

A bicyclo[3.2.1]octanoid neolignan and toxicity of the ethanol extract from the fruit of <Emphasis Type="Italic">Ocotea heterochroma</Emphasis>

A new bicyclo[3.2.1]octanoid neolignan rel-(7S,8R,1′S,2′R,3′S)-Δ8′-2′-hydroxy-5,1′,3′-trimethoxy-3,4methylenedioxy-7,3′,8,1′-neolignan (1) was isolated from ethanol extract from the fruit of Ocotea heterochroma Mez & Sodiro ex Mez as well as the known compounds β-friedelanol (2), meso-dehydroguaiaretic acid (3), and yangambin (4), whose structures were elucidated on the basis of their comprehensive spectroscopic analysis including 2D NMR data. Lethality bioassay using brine shrimp (Artemia salina Leach) was evaluated with the ethanol extract from the Ocotea heterochroma’s fruit. The toxicity of this extract was greater than the toxicity of those fractions obtained in a first solvent partition (benzene, ethyl acetate, and butanol subfractions) and that of a mixture of acetylated 2′-epimers from the new neolignan 1. Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 158–160, March–April, 2009.     

Palladium(II) complexes with R2edda-derived ligands. Part V. Reaction of O,O′-diethyl-(S,S)-ethylenediamine-N,N′-di-2-(3-methyl)butanoate with K2[PdCl4]

The reaction of K₂[PdCl₄] with [(S,S)-H₂(Et)₂eddv]Cl₂ diester (O,O′-diethyl-(S,S)-ethylenediamine-N,N′-di-2-(3-methyl)butanoate) (1) resulted in [PdCl₂{(S,S)-(Et)eddv-κ² N,N′,κO}] (2) complex with one hydrolyzed ester group. The compound was characterized by spectroscopic methods and it was found that the reaction is diastereoselective (¹H and ¹³C NMR; one diastereoisomer of four possible). In addition, the structure of 2 was confirmed by X-ray diffraction analysis, indicating that the product is the (R,R)–N,N′-configured isomer. DFT calculations support the formation of one diastereoisomer of 2.     

New neolignan glycosides and a new cerebroside from <Emphasis Type="Italic">Symplocos caudata</Emphasis>

A phytochemical investigation of the roots of Symplocos caudata Wall (Symplocaceae) resulted in the isolation and characterization of two optical isomers of a neolignan glycoside (1) and a new cerebroside (2). Their structures were elucidated as (7R,8S)-erythro-7,9,9'-trihydroxy-3,3',5'-trimethoxy-8-O-4'-neolignan-4-O-β-D-glucopyranoside, (7S,8R)-erythro-7,9,9'-trihydroxy-3,3',5'-trimethoxy-8-O-4'-neolignan-4-O-β-Dglucopyranoside (1), and 1-O-β-D-glucopyranosyl-(2S,3S,4R,8Z,12E)-2-N-[(2'R)-2'-hydroxyheptacosanoyl]-8,12-docosadiene-1,3,4-triol (2), respectively, on the basis of spectroscopic data (1D and 2D NMR, MS and CD).     

Synthesis,spectroscopic and thermal properties of Pt(II) complexes of some polydentate ligands

The new tetradentate symmetrical (2R,2′S)-1,1′-piperazine-1,4-diyldipropane-2-thiol) (L¹), (2S)-1-[bis(2-aminoethyl)amino]propan-2-ol) (L²), and 2-{(E)-[((1R,2S)-2-{[(1Z)-(2-hydroxy phenyl)methylene]amino}cyclohexyl)imino]methyl}phenol (L³) ligands were synthesized and characterized on the basis of FT-IR, ¹H, ¹³C NMR, EI mass, and elemental analysis. Three commercially available ligands, (2,2′-[ethane-1,2-diylbis(thio)]diethanol (L⁴), 2,2′-dithiodiethanenamine (L⁵), and (2,2′-[ethane-1,2-diyldi(imino)] diethanol (L⁶), were also studied. Pt(II) complexes were characterized by FTIR, elemental analysis and thermal methods. Thermal behaviors of these complexes were investigated in the range 10–1000 °C. Magnetic properties were also studied, and the all complexes were found to be diamagnetic. The structures consist of the monomeric units in which the Pt(II) atoms exhibit square planar geometry. N,N′-bis(salicylidene)-1,2-cyclohexane has been synthesized and characterized by X-ray single crystal diffraction measurement. The ligand crystallizes in monoclinic crystal system and space group, Cc.     

A novel chromone-substituted trimeric dihydroflavonol from <Emphasis Type="Italic">Anogeissus pendula</Emphasis>

A new chromone-substituted dihydrotriflavonol, (2S,3S)[6-{(3S) 3″,5″-dihydroxy-6″-methoxydihydrochromone}5,3′,4′,5′-tetrahydroxy-7-methoxy-3-O-8-dihydroflavone]₂ 3-O-8[6-{(3S) 3″,5″-dihydroxy-6″methoxydihydrochromone}3,5,3′,4′,5′-pentahydroxy-7-methoxydihydroflavonol] was isolated from the leaves of Anogeissus pendula. The structure was determined by UV, ¹H NMR, ¹³C NMR, HMBC, and CD data.     

A new ceramide from the root of <Emphasis Type="Italic">Isatis Indigotica</Emphasis> and its cytotoxic activity

In addition to two ceramides 1-O-β-D-glucopyranosyl-(2S,3R)-N-(2'-hydroxyhexadecanoyl)-octadeca-4E,8Esphingenine (2) and (2S,3S,4R)-N-(2'-hydroxytetracosanoyl)-octadecasphingenine (3), which separated for the first time, a new ceramide 1-O-β-D-glucopyranosyl-(2S,3R)-N-(2'-hydroxyhexacosanoyl)octadecasphingenine (1) was isolated from the traditional Chinese medicinal herb Isatis indigotica. Their cytotoxic effects were evaluated by the MTT method.     

Fluxional rearrangement in congested ruthenium(II) complexes containing pyrimidine- and/or pyridine-based dithioether ligands

The solvento species obtained by the treatment of cis-RuCl₂(N,N-L)₂ [L = di-2-pyridyl sulfide (dps), di-2-pyrimidyl sulfide (dprs)] with AgPF₆, reacted with dithioethers L′ [L′ = 2,6-bis(2-pyridylthiomethyl)pyridine (pytmp), 2,6-bis(2-pyrimidylthiomethyl)pyridine (prtmp) and 2,6-bis{2-(4-methyl)pyrimidylthiomethyl} pyridine (mprtmp)] to afford the compounds [Ru(N,N-L)₂(N,S-L′)][PF₆]₂. The ¹H NMR spectra indicate that L′ is chelated through S and N atoms with the formation of a four-membered ring. As a consequence, the ruthenium and sulfur atoms are stereogenic centers with ∆ and Λ and (R) and (S) configurations, respectively. NMR spectra, at low temperatures, show that two invertomers, of similar abundance, as enantiomeric couples ∆S, ΛR and ∆R, ΛS are present. In the methylene region, four AB systems are observed that in both the species contain two non-equivalent methylene groups. Variable-temperature NMR spectra and EXSY experiments show that the sulfur inversion produces an exchange between the invertomers. The one-dimensional band-shape analysis of the exchanging methylene signals showed that the energy barriers for the process are in the 43–52 kJ mol⁻¹ range. The possible mechanisms of the sulfur inversion are discussed.     

Synthesis of isomeric 2-oxazolidinones from (1<Emphasis Type="Italic">R</Emphasis>,2<Emphasis Type="Italic">R</Emphasis>)-and (1<Emphasis Type="Italic">S</Emphasis>,2<Emphasis Type="Italic">S</Emphasis>)-2-amino-1-(4-nitrophenyl)-1,3-propanediols

A synthesis is reported for (4R,5R)-and (4S,5S)-4-hydroxymethyl-5-(4-nitrophenyl)oxazolidin-2-ones and (1′R,4R)-and (1′S,4S)-4-[hydroxy(4-nitrophenyl)methyl]oxazolidin-2-ones from (1R,2R)-and (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediols. The effect of the experimental conditions on the formation of these compounds was studied. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1562–1570, October, 2007.     

Phenolic constituents from the stems of <Emphasis Type="Italic">Acanthopanax senticosus</Emphasis>

A new phenolic glycoside was isolated from the stems of Acanthopanax senticosus together with sixteen known compounds. The structure of the new compound was determined to be 2,6-dimethoxy-4-[(1E)-3,3-dimethoxy-1-propenyl]phenyl β-D-glucopyranoside (1) by means of physical, chemical, and spectroscopic methods. Of the known compounds, salvadoraside (7), (7R,8S)-dihydrodehydrodiconiferyl alcohol 4,9′-di-O-β-D-glucopyranoside (8), 3-(4-O-β-D-glucopyranosylferuloyl)quinic acid (15), rel-5-(1R,5S-dimethyl-3R,4R,8S-trihydroxy-7-oxa-6-oxobicyclo[3,2,1]oct-8-yl)-3-methyl-2Z,4E-pentadienoic acid (16), and lycoperodine-l (17) were first reported from the title plant. The inhibitory activities of the isolated compounds against α-glucosidase from rat intestine were also reported.     

Two new isomeric lignans from <Emphasis Type="Italic">Eusideroxylon zwageri</Emphasis>

Two new lignans were isolated with two other known compounds, eusiderin A and eusiderin I, from Eusideroxylon zwageri (billian). The two new lignans have isomeric structure. The structures of the new lignans were determined to be (2R,3R,4S)-2,3-dimethyl-6,7-dimethoxy-4-ethoxy (3′,4′,5′-trimethoxybenzene)-1,5-dihydroxytetralin and (2R,3S,4S)-2,3-dimethyl-6,7-dimethoxy-4-ethoxy(3′,4′,5′-trimethoxybenzene)-1,5-dihydroxytetralin. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 303–305, May–June, 2009.     

Secondary metabolites from the endophytic fungus <Emphasis Type="Italic">Annulohypoxylon boveri</Emphasis> var. <Emphasis Type="Italic">microspora</Emphasis> BCRC 34012

A chemical study on the n-BuOH-soluble fraction of the 95% EtOH extract of long-grain rice (Oryza sativa) fermented with the endophytic fungus Annulohypoxylon boveri var. microspora (BCRC 34012) has resulted in the isolation of one new natural azaphilone derivative, designated as annulohypoxyboverin (1) together with 12 known compounds, (3R,6R,7E)-3-hydroxy-4,7-megstigma-dien-9-one (2), α-tocopheryl quinone (3), isofraxidin (4), coumarin (5), cinnamic acid (6), a mixture of palmitic acid (7) and stearic acid (8), N-cis-feruloyltyramine (9), luteolin (10), kaempferol (11), kaempferitrin (12), and 4,5,4′,5′-tetrahydroxy-1,1′-binaphthyl (13). Annulohypoxyboverin (1) contains a dihydrobenzofuran-2,4-dione backbone, 1-hydroxyhexyl side chain, and one γ-lactone ring. Their structures were elucidated by spectroscopic analyses including 1D and 2D NMR experiments, and by HR-ESI-MS. The relative configuration of 1 was confirmed by NOESY experiment. Other known compounds were identified by comparing their spectral data with those of literature data.     

Structural studies of seven homoisoflavonoids, six thiohomoisoflavonoids, and four structurally related compounds

¹H and ¹³C NMR chemical shifts have been determined and assigned based on PFG ¹H, ¹³C HMQC, and HMBC experiments for 3-(4′-X-benzyl)-4-chromenones (Ia, X = CN and Ib, X = NO₂), 3-(4′-X-benzyl)-4-thiochromenones (IIa, X = Cl and IIb, X = Br), (E)-3-(4′-X-benzylidene)-4-chromanones (IIIa–IIIe, X = OCH₃, CH₃, Cl, N(CH₃)₂, Br), (Z)-3-(4′-X-benzylidene)4-thiochromanones (IVa–IVd, X = Cl, Br, F, OCH₃), 2-benzyl-1,2,3,4-tetrahydro-1-naphthol (V), 2-benzyl- and (E)-2-benzylidene-1-tetralones (VI and VII), and (E)-2-benzylidene-1-benzosuberol (VIII). The crystal structures have been determined for the following seven compounds: derivatives of 4-chromanones (IIIa–IIId), 1-tetrahydronaphtol (V), and 1-tetralones (VI and VII). The molecular features and intermolecular interactions in crystal state have been discussed.     

Oxidation of camphor ethylene dithioacetal

(1R,1′R,2S,4R)-1,7,7-Trimethylspiro[bicyclo[2.2.1]heptane-2,2′-[1,3]dithiolane] 1′-oxide, (1R,2S,3′R,4R)-1,7,7-trimethylspiro[bicyclo[2.2.1]heptane-2,2′-[1,3]dithiolane] 1′,1′,3′-trioxide, and (1R,4R)-1,7,7-trimethylspiro[bicyclo[2.2.1]heptane-2,2′-[1,3]dithiolane] 1′,1′,3′,3′-tetraoxide were synthesized by oxidation of camphor ethylene dithioacetal with m-chloroperoxybenzoic acid at different substrate-tooxidant ratios. The structure of the products was proved by IR and NMR spectroscopy and X-ray analysis.     

Unusual transformation of (1<Emphasis Type="Italic">R</Emphasis>,1′<Emphasis Type="Italic">S</Emphasis>,2<Emphasis Type="Italic">S</Emphasis>)-1-(3-diisopropylamino-3-oxopropyl)-2-(1-hydroxyethyl)cyclopropane in the course of the cyclopropylcarbinyl rearrangement

The cyclopropylcarbinyl rearrangement of (1R,1′ S,2S)-1-(3-diisopropylamino-3-oxo-propyl)-2-(1-hydroxyethyl)cyclopropane and the participation of the amide moiety in the intramolecular process smoothly affords the (2′ E,5S)- N,N-diisopropyl-N-[5-(but-2′-enyl)tetra-hydrofuran-2-yridene ] ammonium salt.     

Two new benzoyl esters of glucose from Lagotis yunnanensis

Two new benzoyl esters of glucose 1-O-(E)-4′-methoxybenzoyl-β-D-glucopyranose (1) and 1-O-(E)-4′-methoxybenzoyl-β-D-gluconic acid (2) were isolated from Lagotis yunnanensis, together with six previously known iridoid glucosides. The structures of these compounds were elucidated on the basis of spectral analysis, including 2D NMR spectroscopy. Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 529–530, November–December, 2006.     

New glycosidic and other constituents from hulls of <Emphasis Type="Italic">Oryza sativa</Emphasis>

Three new compounds, 4-hydroxymethylene-7-(9,9,13-trimethylcyclohexyl)-heptanyl-3′,7′,7′-trimethylcyclohexa-2′,4′-dien-1′-oate (1), 1-(n-hexadec-7-enoxy)-6-(n-octadecanoxy)-β-D-glucopyranoside (2), and (Z)-12-hydroxy-9-octadecenoic acid-12-β-D-glucopyranoside (3), along with the known compound hexacosanoic acid (4), were isolated and identified from the rice hulls of Oryza sativa. Their structures were elucidated by 1D and 2D NMR spectroscopic techniques (¹H-¹H COSY, ¹H-¹³C HETCOR, DEPT) aided by EIMS, FABMS, HRFABMS, and IR spectra. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 344–347, July–August, 2007.     

Syntheses based on norfluorocurarine. 2. Reduction and dehydrogenation products

The bisindole compound 2β,16α,2′β,16′β(H)-tetrahydronordihydrotoxiferine consisting of two diastereoisomeric deoxytetrahydronorfluorocurarine moieties was isolated from the reduction mixture of the alkaloid norfluorocurarine. 16-Deformyl-2,16,17,20-tetrahydro-20,21-dehydronorfluorocurarine was produced by dehydrogenation of norfluorocurarine; N(β)-methyldihydrodefluorocurarine, by hydrogenation of fluorocurarine. The structures of the synthesized compounds were established by x-ray structure analyses. The configurations of the asymmetric centers in 2β,16α,2′β,16′β(H)-tetrahydronordihydrotoxiferine were determined as 2S,3S,7R,15S,16R,2′S,3′S,7′R,15′S,16′S. Inversion to the R-configuration at the C15 center was observed in N(β)-methyldihydrodefluorocurarine whereas the configurations 3S and 7R were retained. Atom C2 adopted the S-configuration in 16-deformyl-2,16,17,20-tetrahydro-20,21-dehydronorfluorocurarine.