Two new pentacyclic triterpenoids from Lantana camara LINN

Two new pentacyclic triterpenoids, namely lantanoic acid (1) and camaranoic acid (2), and six known compounds such as lantic acid, camarinic acid, camangeloyl acid, camarinin, oleanonic acid, and ursonic acid were isolated from the aerial parts of Lantana camara LINN. Structures of the new constituents were elucidated by chemical transformation and spectral studies including 1D ((1)H- and (13)C-NMR) and 2D ((1)H-(1)H correlation spectroscopy (COSY), nuclear Overhauser effect spectroscopy (NOESY), (1)H-(1)H total correlation spectroscopy (TOCSY), J-resolved, (1)H-detected heteronuclear multiple quantum coherence (HMQC), and heteronuclear multiple bond connectivity (HMBC)) NMR spectroscopy.     

Two triterpene saponins from Achyranthes bidentata.

Bidentatoside II(1) and chikusetsusaponin V methyl ester (2) are two further triterpene saponins isolated from the roots of Achyranthes bidentata. Chemical and homo and heteronuclear two-dimensional (2D) NMR techniques have led to the structural elucidation of 1 which is a new seco-glycoside of oleanolic acid and the full 1H- and 13C-NMR assignments of 2. These compounds did not show any potentiation of the in vitro cytotoxicity of cisplatin in the HT 29 human colon cancer cell line.     

Bufadienolides and a new lignan from the bulbs of Urginea maritima

Thirty three compounds were obtained from the bulbs of Urginea maritima (Liliaceae). The compounds were identified by means of fast atom bombardment mass spectrometry (FAB-MS), nuclear magnetic resonance (1H-NMR), (13C-NMR), nuclear overhauser effects (NOE) and two dimensional (2D) NMR. Ten of them were new natural compounds. Nine were bufadienolides and only one was lignan in these compounds.     

磷酸体系中有机膦酸类缓蚀剂的鉴定及其电喷雾质谱研究

利用^1H、^13C-NMR和ESI-MS(-Q)等方法对1种新型磷酸体系清洗剂中的有机膦酸类缓蚀剂进行了分析,结果表明该缓蚀剂为羟基乙叉二膦酸和2-羟基膦基乙酸,同时利用ESI-MS(-Q)的多级电离技术对这两种有机膦酸在软电离条件下的碎裂行为进行了研究。     

Three New Compounds from Forsythia Suspensa (Thunb.) Vahl

Forsythiasuspensa(ThUnb.)VahlhasbeenusedintradihonalChinesemedicineforanhiallammatoryandamibacterialpmposes.AnUInberofcompoundssuchasforsythiaside,phillygeninrengyoletc.haVebeenidentifiedl-#fromthefactsofmisplat.AsPartofourstudyontheachveprinciplesoftradihonalChinesemedicine,wereinvestigatCdthechemicalconstitllentsofRsuspensa.heartycompoundshavebeenisolatCdfromthisspecies.ThispaperdescribesthestrUcturalelucidahonofthreenewcompoundsfsuspenolicacid(1),forSythensideA(2),andforsythensideB(3)…     

Caesaldecan, a cassane diterpenoid from the leaves of Caesalpinia decapetala

A new cassane diterpenoid, caesaldecan, was isolated from Caesalpinia decapetala with eight known compounds, spathulenol, 4,5-epoxy-8(14)-caryophyllene, squalene, lupeol, trans-resveratrol, quercetin, astragalin, and stigmasterol. The (1)H- and (13)C-NMR spectra of the new compound were completely assigned by using a combination of 2D NMR techniques, namely, (1)H-(1)H COSY, HMQC, HMBC, and ROESY.     

Preparation on oligostilbenes of isorhapontigenin by oxidative coupling reaction

Four new compounds 1-4 were obtained from an oxidative coupling reaction of (E)-isorhapontigenin using FeCl(3) as oxidant. Their structures and stereochemistry were determined on the basis of spectroscopic evidence [UV, IR, MS, (1)H-, (13)C-NMR, NOE and 2D NMR], and their possible formation mechanisms were also discussed, respectively.     

Two novel dicoumaro-p-menthanes from Gerbera piloselloides (L.) CASS

Two new type dicoumarins (dicoumaro-p-menthanes), named dibothrioclinins I (1) and II (2) were isolated from the roots and rhizomes of Gerbera piloselloides (L.) CASS., collected in Yunnan Province, China. Their structures were elucidated on the basis of MS, 1D ((1)H-NMR, (13)C-NMR, DEPT and NOE) and 2D ((1)H-(1)H COSY, HMQC, HMBC) NMR spectral analyses. The relative structures of the two compounds were established by NOE difference spectroscopy and further confirmed by single-crystal X-ray diffraction studies.     

13C-NMR Sequence Analysis. XVIII. Tacticity of Poly(D,L-β-amino Acids)

D, L-Cis-2-aminocyclobutane-1-carboxylic acid NCA, D, L-cis-and trans-2-aminocyclohexane-1-carboxylic acid N-carboxyanhydride (NCA) and D, L-cis-2-aminocyclohexane-1-carboxylic acid NCA were polymerized under various conditions. The ¹³C-NMR spectra of the resulting β-polyamides measured in trifluoro-acetic acid show splittings of all signals reflecting diads and triads. Poly-D, L-3-aminobutyric acid obtained by anionic polymerization of D, L-4-methyl acetidinone does not display tacticity effects in its ¹³C-NMR spectrum. Hence it is concluded that tacticity effects are observable only if both α- and β-carbons have a substituent. Furthermore, it was found that the reaction conditions do not have a strong influence on the stereospecificity of the NCA-polymerization. In all cases nearly random sequences of D and L-units were obtained.     

Constituents of Salvia microphylla

A new phenolic ester 2-( p-hydroxyphenyl)ethyl eicosaheptanoic acid ester (1) and a known one hexacosylferulate (2) were isolated from the acetone extract of Salvia microphylla. In addition, two sesquiterpenes beta-eudesmol (3) and 8alpha-hydroxy-beta-eudesmol (4), a diterpene carnosic acid 12-methyl ether (12-methoxycarnosic acid) (5), three triterpenes erithrodiol 3-acetate, oleanolic acid, lupeol and beta-sitosterol were obtained as known compounds from this plant extract. The structures of the isolated compounds were elucidated by spectroscopic methods, including one- and two- dimensional 1H- and 13C-NMR and MS spectroscopies. The selected compounds were tested for antimicrobial activity against standard bacterial strains, and only carnosic acid 12-methyl ether showed antimicrobial activity against S. aureus at 78 microg mL(-1).     

Novel sphingolipids from Conyza canadensis

New sphingolipids, 1,3,5-trihydroxy-2-hexadecanoylamino-(6E,9E)-heptacosdiene (1). 1,3,5-trihydroxy-2-hexadecanoylamino-(6E,9E)-heptacosdiene-1-O-glucopyranoside (2). 1,3-dihydroxy-2-hexanoylamino-(4E)-heptadecene (3). have been isolated from Conyza canadensis, along with five known compounds, p-hydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 3,5-dimethoxybenzoic acid, 3beta-hydroxyolean-12-en-28-oic acid, and 3beta-erythrodiol, isolated for the first time from this species. Their structures were determined by spectroscopic methods ((1)H- and (13)C-NMR, IR and MS) and two dimensional (2D)-NMR experiments.     

Separation and identification of Taxifolin 3-O-glucoside isomers from Chamaecyparis obtusa (Cupressaceae)

Taxifolin 3-O-glucoside isomers, [(2R, 3R)-, (2R, 3S)-, (2S, 3R)- and (2S, 3S)-] were isolated from leaves of Chamaecyparis obtuse (Cupressaceae). Their structures were elucidated on the basis of UV, MS, CD, 1H- and 13C-NMR spectral data, including 2D shift correlation. It was found that the compounds could be distinguished by the use of 1H- and 13C-NMR spectral data.     

Fused heterocycles: synthesis of some new imidazo[1,2-a]- pyridine derivatives

Some new thiazolidines and spirothiazolidines derived from hydrazones of 2-methylimidazo[1,2-a]pyridine-3-carboxylic acid hydrazide, a bioisosteric derivative of isoniazid, were synthesized and characterized by analytical, IR, (1)H- and (13)C-NMR and mass spectral data. Some of the newly synthesized compounds were screened for their antimycobacterial activities. None of the tested compounds showed significant in vitro antituberculous activity at 6.25 mirog/mL (MIC rifampin 0.031 microg/mL).     

A new benzofuranic acid from the leaves of Rhus alata

From leaves of Rhus alata, one new benzofuranic acid named [(2E)-3-(4-hydroxy-5,7-dimethyl- benzo[3,4-b] furan-6-yloxy)-prop-2-enoic acid has been isolated together with eight known compounds: dimethyl ester of terephthalic acid, beta-amyrin, friedelin, lupeol, beta-sitosterol, oleanolic acid, taraxerone and ethyl gallate. Structural elucidations were done on the basis of chemical and physical data (IR, UV, 1H-NMR, 13C-NMR and MS spectra).     

New eudesmane derivatives and other sesquiterpenes from the epigeal parts of Dittrichia graveolens

In bioassay-guided searches for novel bioactive natural products from higher plants of the Egyptian flora, two new eudesmane sesquiterpene derivatives, 3alpha-hydroxyilicic acid methyl ester (1) and 2alpha-hydroxy-4-epi-ilicic acid (2), together with 11 known sesquiterpenes were isolated from bioactive fractions of the active epigeal parts extracts of Dittrichia graveolens (L.) GREUTER (Asteraceae) growing in the coastal regions of northwestern Egypt. Four other known sesquiterpene lactones with different carbon skeletons, named 2alpha-hydroxy-2R-xanthalongin (8), 4-epi-isoinuviscolide (9), 8-epi-helenalin (10), and bigelovin (11), were also isolated for the first time from the same source. The stereochemical structures of the isolated compounds were elucidated on the basis of physical and spectroscopic methods including UV, IR, 1H-, 13C-NMR, distortionless enhancement by polarization transfer, 2D NMR, 1H-1H correlation spectroscopy, 1H-13C heteronuclear single-quantum coherence, 1H-13C heteronuclear multiple-bond connectivity, 1H-1H nuclear Overhauser effect spectroscopy experiments, and high-resolution mass spectrometry, as well as some chemical transformations. The antimicrobial, antiinflammatory, and antipyretic activities of D. graveolens extracts and chromatographic fractions were carried out and the various bioactivities of our findings are discussed.     

Biosynthesis of tetrapetalones

The biosynthesis of tetrapetalones (tetrapetalones A, B, C, and D) in Streptomyces sp. USF-4727 was studied by feeding experiments with [1-13C] sodium propanoate, [1-13C] sodium butanoate, [carbonyl-13C] 3-amino-5-hydroxybenzoic acid (AHBA) hydrochloride, and [1-13C] glucose, followed by analysis of the 13C-NMR spectra. These feeding experiments revealed that the four tetrapetalones were polyketide compounds constructed from propanoate, butanoate, AHBA, and glucose. The tetrapetalone biosynthetic pathway was also suggested in this study. In this pathway, tetrapetalone A (1) is synthesized by polyketide synthase (PKS) using AHBA as a starter unit, then the side chain of 1 is subjected to acetoxylation to produce tetrapetalone B (2). Additionally, 1 is oxidized and transformed into tetrapetalone C (3). In a similar way, 2 is converted to tetrapetalone D (4). Therefore, the biosynthetic relationship of the four tetrapetalones was indicated.     

Structure elucidation and complete NMR spectral assignments of four new diterpenoids from Smallantus sonchifolius

Four new diterpenoids, named smaditerpenic acid A-D, together with five known compounds, were isolated from the H(2)O extract of the leaves of Smallantus sonchifolius (yacon) cultivated in Liaoning, China and their structures were elucidated on the basis of one- and two-dimensional NMR (including (1)H, (13)C-NMR, (1)H-(1)H COSY, HSQC, TOCSY, HMBC, and ROESY), electrospray ionization mass spectrometry (ESI-MS), and chemical methods.     

Synthesis and characterization of novel chiral NHC-palladium complexes and their application in copper-free Sonogashira reactions

A new series of chiral N-heterocyclic carbene (NHC) palladium complexes were synthesized from a relatively inexpensive amino acid, l-phenylalanine. All these compounds were fully characterized by (1)H-NMR, (13)C-NMR and elemental analysis. The X-ray molecular structures of two of the complexes were reported. The catalytic activity of the four palladium complexes was successfully tested in the Sonogashira reaction under copper free conditions in air. The palladium complex 3a provided good activity in the Sonogashira coupling reaction.     

Synthesis and spectroscopic studies of new Schiff bases

Five novel Schiff bases have been prepared from o-formylphenoxyacetic acid and a series of aminothiazoles to form a number of potentially biologically active compounds. The structures of these Schiff bases have been characterized using IR and (1)H-and (13)C-NMR spectroscopy.     

Naturally occurring iridoids. A review, part 1

A compilation of new naturally occurring iridoid glycosides, iridoid aglycones, iridoid derivatives and bis-iridoids reported during 1994-2005 is provided with available physical and spectral data: mp, [alpha]D, UV, IR, 1H- and 13C-NMR as well as natural source with family and references. 418 compounds with 202 references are cited.