Buzonamine, a new alkaloid from the defensive secretion of the millipede, Buzonium crassipes

GC-MS analysis of the defensive secretion from the millipede Buzonium crassipes showed three volatile components, beta-pinene (35%), limonene (6%) and a new alkaloid, buzonamine (59%). Buzonamine had an HRMS molecular ion at m/z=221.1785 (calculated for C(14)H(23)NO, 221.1781), 14 carbons in the 13C-NMR and 23 hydrogens by SFORD, DEPT and APT experiments. All distinct 1H nuclei were assigned to 13C resonances with 2D 1H-13C COSY data, and the final structure was determined by 1H-1H COSY, 1H-13C HMBC and nOe experiments. Buzonamine contains four rings including an epoxy group and a tertiary nitrogen. beta-Pinene, limonene or buzonamine, kept the mound nesting ant, Formica obscuripes, from eating mealworms (Tenebrio molitor) treated with 1mg of the chemical. A 150mg millipede expels 4mg of secretion.     

Clitolactone: a banana slug antifeedant from Clitocybe flaccida

Clitolactone, 5-(chloromethyl)-3-methyl-2(5H)-furanone, was isolated from sporocaps of the mushroom Clitocybe flaccida. The structure was determined by HRMS, EIMS, (1)H & (13)C NMR, 2D (1)H-(13)C COSY and (1)H-(1)H COSY. This mushroom is not eaten by the banana slug Ariolimax columbianus (Gould), a mycophagist from the temperate rain forests of the Pacific Northwest. Clitolactone acts as an antifeedant because these slugs rejected 1.0 cm(2) pieces of lettuce treated with 25 μg of clitolactone.     

Abruquinone A,B,D,E,F and G from the Root of Abrus precatorius

Eight flavonoids have been isolated from the root of Abrus precatorius L. Among them, six isoflavanquinones, designated (3R)-abruquinone A, B, D and E, (3S)-abruquinone F and G, are characterized by chemical and spectral means including 1H-1H COSY, 1H-13C COSY and CD methods.     

A dimeric ArC2 compound from Peperomia pellucida

Pellucidin A, a novel dimeric ArC2 compound, together with dill-apiol have been isolated from the aerial parts of Peperomia pellucida. The structure of pellucidin A was established by 1D and 2D NMR spectroscopy (1H-1H COSY; 1H-13C COSY; DEPT; NOESY and double irradiation) and other spectroscopic techniques. The biogenesis of pellucidin A is also briefly discussed.     

Two Novel Diterpenoid Alkaloids Isolated from the Roots of Aconitum brevicalcaratum

Two new diterpenoid alkaloids were isolated from the roots of Aconitum brevicalcaratum Diels. They were acobretine D ( Ⅰ )and acobretine E ( Ⅱ ), and the structures of which were identified on the basis of spectroscopic evidences (IR, MS, 1 H and 13C-NMR) and confirmed by chemical transformations. The 1 H and 13C chemical shifts of the hydrochloride of Ⅰ were assigned in relation to of 1 H-1 H COSY and 13C-1 H COSY.     

Re-characterization of three conjugated linolenic acid isomers by GC-MS and NMR

Conjugated linolenic acids (CLN) refer to a group of octadecatrienoic acids with three conjugated double bonds. Minor positional and geometrical differences among CLN isomers make their separation and identification difficult. We have used GC-MS and NMR to study three common CLN isomers namely alpha-eleostearic acid, beta-eleostearic acid and punicic acid, finding that some signals of olefinic carbon atoms in NMR spectra were mistakenly assigned in the literature. The present study was therefore undertaken to re-characterize the location of CC double bonds and assign the chemical signals of proton and carbon atoms using (1)H NMR, (13)C NMR, (1)H-(1)H two-dimensional correlation spectra ((1)H-(1)H COSY) and (13)C-(1)H two-dimensional correlation spectra ((13)C-(1)H COSY). The geometrical structure of double bonds in these three CLN isomers was identified using homonuclear decoupling technique.     

A New Diterpene Glycoside in Aster ageratoides Turcz.

A new natural diterpene glycoside was isolated from Aster ageratoides Turcz. Its structure was elucidated by means of IR, MS (FAB, EI), NMR (1H-, 13C-, DEPT), 2D-NMR (1H-1H COSY, 13C-1 H COSY, J-resolved, CoLoC) spectra and chemical method as 16β, 17-dihydroxy- (—) -kauran- 19-oic acid-β-D-glucopyanosyl ester.     

Structure elucidation by NMR spectroscopy of a new acetylated saponin from Centratherum anthelminticum

A new glycosylated triterpene has been isolated from the seeds of Centratherum anthelminticum, a medicinally important plant. The structural analysis of its acetylated derivative was performed by 1H, 13C NMR, 1H-1H COSY, HMQC, HMBC and DEPT spectroscopy. The saponin was shown to contain hederagenin and six sugar residues forming two glycosyl chains. The complete structure of the saponin was established as 3-O-[beta-D-glucopyranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl]-28-O-[beta-D-glucuronopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->3)-beta-D-glucopyranosyl]-hederagenin.     

Constituents of Lepidium meyenii 'maca'.

The tubers of Lepidium meyenii contain the benzylated derivative of 1,2-dihydro-N-hydroxypyridine, named macaridine, together with the benzylated alkamides (macamides), N-benzyl-5-oxo-6E,8E-octadecadienamide and N-benzylhexadecanamide, as well as the acyclic keto acid, 5-oxo-6E,8E-octadecadienoic acid. The structure elucidation of the isolated compounds was based primarily on 1D and 2D NMR spectroscopic analyses, including 1H-1H COSY, 1H-13C HMQC, 1H-13C HMBC and 1H-1H NOESY experiments, as well as from 1H-15N NMR HMBC correlations for macaridine and N-benzylhexadecanamide.     

黄射干的异黄酮类成分

从黄射干Ｉｒｉｓｔｅｃｔｏｒｕｍ的甲醇抽提物中分到５个异黄酮：鸢尾黄酮甲素（１）,鸢尾花素（２）,野鸢尾黄酮（３）,鸢尾黄酮（４）,鸢尾黄酮甙（５）。化合物（１）和（２）系首次从黄射干中分到。所有成分经详细光谱分析确定。     

Isotope-edited 1D and 2D n.m.r. spectroscopy of 13C-substituted carbohydrates.

Three isotope-edited n.m.r. methods have been applied to selectively 13C-substituted monosaccharides and nucleosides to simplify their spectra and/or measure 1H-1H, 13C-1H, or 13H-13C spin-couplings detected via the labeled site. 1D INADEQUATE spectra allowed the selective detection of the natural-abundance carbons that are spin-coupled to the labeled carbon, and adjustment of the mixing time permitted further discrimination between one-bond and longer-range 13C-13C coupling pathways. Geminal and vicinal 13C-1H coupling constants were determined from the analysis of 1H-1H COSY cross-peaks for those protons coupled to the labeled carbon. Long-range 13C-(HETCOR) and 1H-detected (HMBC) 13C-1H chemical-shift correlation spectra permitted the selective observation of those protons coupled to the labeled site, and JH,H values were measured from data projections. The implications of these methods for structural studies of more complex systems is briefly discussed.     

The conversion of 3-C-beta-D-galactopyranosyl phloroacetophenone to a spiroketal derivative

Treatment of 3-C-beta-D-galactopyranosylphloroacetophenone in hot water with a catalytic amount of p-toluenesulfonic acid afforded a spiroketal compound as the main product. The chirality of the spiro carbon of the product was R, which is the opposite of the spiroketal obtained by the conversion of 3-C-beta-D-glucopyranosyl phloroacetophenone under identical conditions. The structure was determined by 1H-1H COSY, 1H-13C COSY, NOESY and HMBC spectroscopy.     

Cladocalol, a pentacyclic 28-nor-triterpene from Eucalyptus cladocalyx with cytotoxic activity

A formylated triterpene named cladocalol has been isolated from the leaves of Eucalyptus cladocalyx, together with ursulolactone acetate, ursolic acid, 3 beta-acetate-12,20(29)-lupadien-28-oic acid, beta-sitosterol and the known flavonoid eucalyptine. Their structures were mainly established by extensive NMR studies (1H NMR, 13C NMR, DEPT, 1H-1H COSY, HSQC, HMBC) and mass spectroscopy as well as by X-ray crystallographic analysis. In this paper, we report on the cytotoxic effect induced by cladocalol and its derivatives on the myeloid leukemia cell line HL-60.     

栗柄金粉蕨的黄酮类成分

从栗柄金粉蕨（ Ｏｎｙｃｈｉｕｍ ｌｕｃｉｄｕｍ ） 地上部分的甲醇抽提物中分到１０ 个成分, 经详细的一维、二维核磁数据分析, 它们被鉴定为： 木犀草甙（１） , ３ , ７ － 二甲基槲皮素（２） , 高山甙Ｂ （３） , 金粉蕨素（４） , 栗柄醇（５） , 金粉蕨醇Ｂ（６） , β－ 谷甾醇（７） , 胡萝卜甙（８） ,齐墩果酸（９） 和蔗糖（１０） 。栗柄醇系新成分。１ , ２, ９ 系首次由金粉蕨属分到。     

Complete 1H and 13C NMR assignment of mono-sulfated galactosylceramides with four types of ceramides from human kidney

The full assignment of 1H and 13C NMR signals of galactosylceramide 3-sulfate (galactosyl sulfatide) and 1H signals of galactosylceramide 6-sulfate was achieved by using 1H-1H DQF-COSY and 1H-13C heteronuclear COSY. Analyses were performed on a mixture of galactosyl sulfatides with four representative ceramide types consisting of a combination of non-hydroxy or 2-hydroxy fatty acids and sphingenine or 4D-hydroxysphinganine (trihydroxysphinganine) as the long-chain bases. The 1H and 13C NMR parameters of galactosyl sulfatide with 4-hydroxysphinganine as well as 13C signals of complex lipids with 4-hydroxysphinganine were elucidated for the first time. Not only sulfation of the galactosyl residue, but also modification of the aglycon, including hydroxylation of fatty acids and hydration of the double bond in sphingoid bases, altered the chemical shifts substantially. In addition, the unique long-range coupling constants, 4J(H,H) and 5J(H,H), in the galactosyl residue of galactosyl sulfatide could be determined.     

Two-dimensional concurrent HMQC-COSY as an approach for small molecule chemical shift assignment and compound identification

Chemical shift assignment is the first step toward the structure elucidation of natural products and other chemical compounds. We propose here the use of 2D concurrent HMQC-COSY as an experiment for rapid chemical shift assignment of small molecules. This experiment provides well-dispersed (1)H-(13)C peak patterns that are distinctive for different functional groups plus (1)H-(1)H COSY connectivities that serve to identify adjacent groups. The COSY diagonal peaks, which are phased to be absorptive, resemble (1)H-(13)C HMQC cross peaks. We demonstrate the applicability of this experiment for rapidly and unambiguously establishing correlations between different functional groups through the analysis of the spectrum of a metabolite (jasmonic acid) dissolved in CDCl(3). In addition, we show that the experiment can be used to assign spectra of compounds in a mixture of metabolites in D(2)O.     

Monoepoxy octadecadienoates and monoepoxy octadecatrienoates 1: NMR spectral characterization

Methyl esters of gamma-linolenic acid, alpha-linolenic acid and stearidonic acid were epoxidised using m-chloroperbenzoic acid to achieve nine cis-monoepoxy-C18 fatty acid methyl esters (FAMEs), including novel methyl cis-monoepoxy derivatives of stearidonic acid and a cis-6,7-epoxy derivative of gamma-linolenic acid. These nine monoepoxy FAMEs were purified by normal-phase HPLC, identified by LC-MS, 1H and 13C NMR, and characterized by mass spectrometry and NMR spectroscopy. This study is focused on structural characterization of these C18 monoepoxy FAMEs using techniques in NMR spectroscopy including 1H, 13C, 1H-1H correlated spectroscopy (COSY) and 1H-13C heteronuclear correlation (HETCOR). The proton and carbon NMR chemical shifts of the epoxide, the double bonds, and the interrupted methylenes are assigned. Also discussed is an interpretation of the 1H and 13C NMR spectra of these monoepoxides including the changes in the 13C resonance of the olefinic carbons on the neighboring double bonds resulting from epoxide formation.     

Glycosylamines of 4,6-O-butylidene-alpha-D-glucopyranose: synthesis and characterization of glycosylamines, and the crystal structure of 4,6-O-butylidene-N-(o-chlorophenyl)-beta-D-glucopyranosylamine

A total of nine glycosylamines of 4,6-O-butylidene-alpha-D-glucopyranose were synthesized using primary amines having various groups in their ortho- or para-positions. Among these, six are monoglycosylamines, including one primary glycosylamine, and three are bis-glycosylamines. All these compounds were characterized by 1H, 1H-1H COSY, 1H-13C COSY and 13C NMR spectroscopy and FTIR spectra. The FAB mass spectra provided the molecular weights of the products by exhibiting the corresponding molecular ion peaks. The crystal structure of 4,6-O-butylidene-N-(o-chlorophenyl)-beta-D-glucopyranosylamine revealed the C-1 glycosylation, the beta-anomeric nature, and the 4C1 chair conformation of the saccharide unit in the product. In the lattice two types of dimers exist. While one type of dimer is formed through O-H...O type of interactions, the other type is formed via C-H...O type of interactions. In the direction of these C-H...O type of interactions, the dimeric units are connected to form a chain.     

New sequential-assignment routes of nucleic acid NMR signals using a [5'-(13)C]-labeled DNA dodecamer

NMR signal assignments for DNA oligomers have been performed by the well-established sequential assignment procedures based on NOESY and COSY. The H4'/H5'/H5' resonance region is congested and difficult to analyze without the use of isotope-labeled DNA oligomers. Here a DNA dodecamer constructed with 2'-deoxy[5'-(13)C]ribonucleotides, 5'-d(*C*G*C*G*A*A*T*T*C*G*CG)-3' (*N = [5'-(13)C]Nucleotide), was prepared in an effort to analyze the H4'/H5'/H5' resonance region by 2D 1H-13C HMQC-NOESY. In the C5' and H1' resonance region, weak and strong cross peaks for C5'(i)-H1'(i) and C5'(i)-H1'(i-1), respectively, were found, thus enabling the sequential assignment within this region. A similar sequential assignment route was found between C5' and H2'. Proton pair distances evaluated from the canonical B-DNA as well as A-DNA indicated that these sequential-assignment routes on a 2D 1H-13C HMQC-NOESY spectrum work for most nucleic acid stem regions.     

Alkaloids from Toddalia aculeata

Two alkaloids N-methyl-4-hydroxy-7-methoxy-3-(2,3-epoxy-3-methylbutyl)-1H-quinolin-2-one (1) and 3-(2,3-dihydroxy-3-methylbutyl)-4,7-dimethoxy-1-methyl-1H-quinolin-2-one (2a) have been isolated from CH(2)Cl(2):methanol (1:1) and methanol extracts of leaves and stems of Toddalia aculeata. Their structures along with that of 15 other compounds, of which three are isolated for the first time from genus Toddalia, were established by their detailed spectral studies including 2D NMR viz. (1)H-(1)H COSY, (1)H-(13)C COSY, and HMBC.