The structure of the lignin in the cortex and pith of elephant grass (Pennisetum purpureum) stems was studied both in situ and in isolated milled "wood" lignins by several analytical methods. The presence of p-coumarate and ferulate in the cortex and pith, as well as in their isolated lignins, was revealed by pyrolysis in the presence of tetramethylammonium hydroxide, and by 2D NMR, and indicat...

Rapid injection of pyruvonitrile or benzoyl cyanide into solutions of Me2CuLi in THF-d8 at -100 °C gave complexes that were stable at this temperature. 1D NMR with multiply labelled substrates ((13)C/(15)N) and 2D NMR ((1)H/(13)C) identified them as the first cuprate-carbonyl π-complexes.

[Structure: see text] OH...OH hydrogen bond mediated scalar couplings have been observed in acyclic syn- and anti-1,3-diols using a 2D 1H COSYLR NMR experiment and quantified with an uncertainty of +/-0.02 Hz with a selective-excitation spin-echo NMR experiment. A theoretical investigation confirmed the importance of the hydrogen bond in mediating the spin-spin coupling in these systems.

The leaves of Beilschmiedia brevipes provided a new benzylisoquinoline alkaloid: (6,7-dimethoxy-4-methylisoquinolinyl)-(4'-methoxyphenyl)-methanone (1) and O,O-dimethylannocherin A (2), a new natural compound which has been synthesized before. Complete 1H- and 13C-NMR data of both compounds were reported. The structures were established through various spectroscopic methods notably 1D- and 2D-N...

The epimeric sesquiterpene alcohols (14R)-beta-oplopenol and (14S)-beta-oplopenolwere obtained by LiAlH(4) reduction of beta-oplopenone. The complete (1)H- and (13)C-NMR assignments of these two new sesquiterpene alcohols have been made using 1D and 2D NMR techniques, including COSY, NOESY, HSQC, HMBC experiments.

A new O-terpenoidal coumarin 1, named hekumarone, was isolated from the leaves and twigs of Clausena anisum-olens Merr.(Rutaceae) collected in Hekou County in Yunnan Province, P.R. China. Structure elucidation and unambiguous NMR assignments for the title compound was carried out on the basis of 1D and 2D NMR experiments.

BACKGROUND The objective of this study was to identify molecular alterations in the human blood serum related to bipolar disorder, using nuclear magnetic resonance (NMR) spectroscopy and chemometrics. METHODS Metabolomic profiling, employing 1H-NMR, 1H-NMR T2-edited, and 2D-NMR spectroscopy and chemometrics of human blood serum samples from patients with bipolar disorder (n = 26) compared wit...

The known flavone, chrysin (1) and the known flavone glycoside, chrysin-7-O-(β-D-glucopyranoside) (2) together with vomifoliol, loliode and cinnamic acid have been isolated for the first time from the leaves and flowers of Calycotome spinosa (L.). Lamk, theirs structures were established on the basis of spectroscopic technical; H-, C-NMR, 2D NMR and MS (I.E).

Small molecules of biological origin continue to yield the most promising leads for drug design, but systematic approaches for exploring nature's cache of structural diversity are lacking. Here, we demonstrate the use of 2D NMR spectroscopy to screen a library of biorationally selected insect metabolite samples for partial structures indicating the presence of new chemical entities. This NMR-sp...

Insights into the interaction of the [Re(H2O)3(CO)3]+ complex (1) with the DNA fragment d(CpGpG) have been obtained by one- (1D) and two-dimensional (2D) NMR spectroscopy. The H8 resonances of the single major [Re(H2O)d(CpGpG)(CO)3]- adduct (2) exhibit pH-independent chemical shift changes attributable to metal N7 binding. The structure of this adduct has been characterized by molecular modelin...