Correlated spectroscopy COSY and

On the basis of their 13C NMR assignments (see below), 111—111 correlation spectroscopy (COSY) and H-13C COSY experiments allowed to assign the H NMR data of a series of sparteine analogues and derivatives (compounds 24-27). These data are collected in Table 2 <2003JST275>. Detailed 111 NMR assignments for other sparteine derivatives are also available in the literature (see, for instance, <2005JST75>). 

Two-Dimensional Correlation Spectroscopy (COSY) and Total Correlation Spectroscopy (TOCSY)... 

The 2D ESR technique was developed by Freed and his co-workers (Freed, 2000 Gorcester et al., 1990 Freed and Mobius, 1992) by the analogy of the well-known NMR two-dimentional spectroscopy, correlation spectroscopy (COSY) and spin-echo correlation spectroscopy (SECSY) (Wiitrich, 1986 and references tsherein). 

The cis stereochemistry adopted by lactam 9 in the course of synthesis was elucidated by H NMR, H- H correlation spectroscopy (COSY), and nuclear Overhauser effect (NOE) experiments taking into account the signals for the hydroxyethyl and benzyl fragments <2002OL2637>. 

Fattorusso and co-workers identified a component of wormwood called artar-borol. Correlation spectroscopy (COSY) and rotating frame nuclear overhauser effect spectroscopy (ROESY) experiments allowed for deduction of four possible diastereomeric structures of artarborol, 2-5. Low energy conformers of 11-14 were obtained through a molecular mechanics (MM) search. These conformers were screened to identify those having a dihedral angle of around 90 for the C-8 and C-9 protons due to a low coupling constant between these protons. Only conformers of 11 and 13 satisfied this criterion. Next, five low energy conformers, two... 

The stereochemistry of compounds 60-63 was fully determined by various NMR techniques such as nuclear Overhauser effect (NOE), correlation spectroscopy (COSY), and nuclear Overhauser enhancement spectroscopy (NOESY) <1996MRC52>. The conformation of the 2,3-butanedione trimer 64 and similar compounds has been examined by NMR at —90°C <2000T10005>. 

In spite of the fact that NMR spectroscopy has been used routinely in characterization of organic compounds, no systematic studies appear on the spectral properties of the parent tricyclic rings. This is mainly due to the lack of these compounds and to the difficulty of unambiguous assignments of the resonance signals in earlier times. The H NMR spectral data of some pyrrolonaphthyridine derivatives are shown below, assignments being made on the basis of H- H correlation spectroscopy (COSY) and HETCOR spectra <93(H)(36)1945,93(H)(36)2513>. 

The basic skeleton of casearin A (12) was elucidated by H-iH and H-correlated spectroscopy (COSY) and 2D-incredible natural abundance double quantum transfer experiment (INADEQUATE). The positions of ester functions were determined by the long range COSY... 

Noroxohomoyessotoxin (noroxohomoYTX, 10, Eigure 13.1), a new addition to the class of YTXs, was reported in 2001. It was isolated from the digestive glands of mussels collected in 1998 from the northern Adriatic coast of Italy. The polycyclic skeletal structure was mainly assigned on the basis of homonuclear 2D NMR spectral data obtained from correlation spectroscopy (COSY) and HOmonuclear HArtmann HAhn (HOHAHA) experiments negative ion EAB MS/MS provided further valuable information to confirm the structure. 

The homonudear 2-D NMR experiments that use I-coupling indude the correlation spectroscopy (COSY, and variants induding gradient-selected COSY or gCOSY, double-quantum filtered COSY or DQF-COSY) experiment, the total correlation spectroscopy (TOCSY) experiment, and the incredible natural abimdance double quantum transfer experiment (INADEQUATE) [3]. 

For simple systems such as stocks obtained from plant tissues, NMR spectra include a wealth of peaks. Generally, peak assignment of IH NMR spectra can be done by addition of pure compounds to solutions, by comparison of published data and further confirmation can be obtained throu 2D (correlation spectroscopy, COSY, and total correlation spectroscopy, TOCSY) experiments. Thus, each major carbohydrate was identified by peak assignment of ID H NMR spectra and as many peaks overlapped in the amino acids and organic acid region (between 1 and 3.5 ppm), identification was performed using 2D IH NMR spectra (COSY). 

The hydroformylation of an unsaturated steroid proceeded in high chemo-, diastereo-, and regioselectivity (Scheme 14.9) with diastereoselectivity assigned by correlation spectroscopy (COSY), and heteronuclear correlation spectroscopy (HETCOR) spectra." This reaction of this trisubstituted alkene used a [Rh(nbd)Cl]2 precursor (nbd) and P( -Bu)3 as a ligand, at 120°C and pressures of 100-120 bar. 

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