DEPT-HMQC-TOCSY

Direct ( Jch) responses were suppressed by the 180°/90° pulse pair (Crouch et al. 1992b Martin et al. 1992). Responses arising through a relay from protons on a methylene carbon appear with positive intensity and are denoted in this presentation by the solid responses. Relayed signals arising through transfer from protons on a methine or methyl carbon appear with negative intensity and are denoted by the open contours 

The DEPT-edited HMQC-TOCSY spectrum of ajmaline (4) is illustrated in Fig. 14. The spectrum was acquired using the pulse sequence shown in Fig. 13 modified to include a 180°/90° pulse pair position in 

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The second Chilocorini species studied, Chilocorus cacti, contained several alkaloids closely related to the former. The structure of the heptacyclic chilo-corine A (19) was deduced from a series of NMR experiment (DEPT, HMQC, DQ-COSY, TOCSY) and from a comparison of its spectral properties with those of exochomine (18) from which it differ by having two C-C linkages between the two tricyclic partners. However, the configuration at the asymmetric center in the azaacenaphthylene ring was not established [33]. 

Given are the structure and H, 13C/DEPT, COSY, 1-D TOCSY, 2-D TOCSY, HMQC, HMQC-TOCSY, HMBC, and ROESY spectra for raffinose. Confirm the structure, assign all protons and carbons, and show as many correlations as possible. 

The combined information from the l3C/DEPT, COSY, TOCSY, and HMQC enables us to assign all protons in the 3H spectrum except those that are exchanging rapidly (i.e., the carboxyl and free amino protons) and all of the non-quaternary carbon resonances in the 13C spectrum. There is no need to assign the rapidly exchanging protons, and the non-quaternary carbons will be assigned during the sequencing discussion. 

HSQC) or heteronuclear multiple quantum correlation (HMQC). The combined experiments such as 2D HSQC(HMQC)-TOCSY experiments are powerful tools for the assignment of the 13C and 11 resonances belonging to the same sugar residue providing enhanced dispersion of TOCSY correlations in the carbon dimension. More recendy, different carbon multiplicity editing methods, for example, DEPT (distortionless enhanced polarization transfer)-HMQC and E-HSQC, have been developed to reduce the complexity of proton-carbon correlation spectra and to enhance the resolution by narrowing the applied spectral window.11... 

The complex structure isolated from Scleranthus uncinatus, 5,7-dihydroxy-3 -meth-oxy-4 -acetoxyflavone-8-C-p-D-xylopyranoside-2 -0-glucoside, was determined by using ID NMR ( H, C, DEPT) and 2D NMR (H-COSY, TOCSY, HMQC, HMBC, NOESY) data sequence and linkage of the sugar chain and acylation site were confirmed by observation of inter-residue NOEs in the NOESY spectrum. 

The serine residue can be accounted for by starting with the carbon resonance at 62 ppm. DEPT indicates another methylene group, and the HMQC shows that it correlates with coincident protons resonating at 3.85 ppm. These protons overlap with another proton. Careful line drawing in the DQF-COSY (or more easily in the TOCSY spectrum) suggests correlation with a proton at 4.48 ppm. This proton shows a correlation to a carbon atom at 56 ppm in the FIMQC spectrum. That proton also shows a correlation to an amide proton at... 

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