HH COSY Experiment

All componnds were determined by NMR speetroseopy (Table 37.1) and diagnostic spin-spin interactions were identified with the aid of HH COSY experiments (Fig. 37.1). The exo-location of the substituent on C. was eonfirmed by the faet that Hg showed no significant interaction with also showed a eross-peak as a result of W-coupling to H.. ... 

The HH COSY experiment in proton magnetic resonance is a quick alternative to spin... 

Figure 2.10. HH COSY diagram of quinoline (11) [(CD3)2CO, 95% v/v, 25°C, 400 MHz, 8 scans, 256 experiments]. (a) Stacked plot (b) contour plot...

Figure 2.11. Proton-Proton shift correlations of a-pinene (1) [purity 99 %, CDCls, 5 % v/v, 25 °C, 500 MHz, 8 scans, 256 experiments], (a) HH COSY (b) HH TOCSY (c) selective one-dimensional HH TOCSY, soft pulse irradiation at Sh = 5.20 (signal not shown), compared with the NMR spectrum on top deviations of chemical shifts from those in other experiments (Fig. 2.14, 2.16) arise from solvent effects...

Figure 2.12. Two-dimensional (2D-)INADEQUATE diagram of 1-butanol (12) [ CDajzCO, 95% v/v, 25°C, 50 MHz, 128 scans, 128 experiments], (a) Contour plot with the AB systems of bonded C atoms on the horizontal axis (b) plots of the three AB systems of the molecule obtained from (a) (c) contour plot of the symmetrised INADEQUATE experiment showing the AB or AX systems of bonded C atoms in the HH COSY format (cross signals on the axes perpendicular to the diagonal)...

The NMR experiments 55 are obtained from actinomycin D in order to check the amino acid sequence, to assign proton-proton and some carbon-proton connectivities, and to deduce informations concerning proton distances and the spatial structure of both cyclopentapeptide lactone rings. Conditions CDCI3, 10 mg per 0.3 ml, 25 °C, 500 MHz H), 125 MHz ( C). (a) HH COSY plot ... 

Carbon atoms and protons are assigned by means of the proton-carbon connectivities as identified in the HC HSQC and HMBC experiment (b and c). The latter also permits the derivation of the connection of the ethyl groups to the porphyrin ring. The cross signals in the relevant part a of the HH COSY plot (a) are used to connect the methyl and methylene subunits to the ethyl groups. 

There are several variations of correlation spectroscopy, all giving rise to different, complementary data. We have already met HH (homo-nuclear) COSY earlier in this chapter (Section 4.5). An obvious extension to the COSY experiment is to use it for heteronuclear correlation, e.g. correlation of all the H and C signals in a molecule... 

Load the raw data of the 2D phase sensitive COSY experiment of glucose D NMRDATA GLUCOSE 2D HH GHHCODF 001001. SER. Calculate the spectrum and proceed as above, but use the Syma command for symmetrization. Compare the results obtained with/without symmetrization. 

A compound with the elemental composition C15H22O , was isolated from the methanol extract of the Chilean medicinal plant Centaurea chilensis (Compositae) 41. What is the structure of the natural product, given the NMR experiments 47 Conditions CD3OD, 15 mg per 0.3 ml, 400 MHz i H), 100 MHz (13C). (a) HH COSY plot from h= 1.2 to 3.5, 47a ... 

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