CMR spectra

In spite of the above limitations 13C NMR or (CMR) spectra are more easily interpreted and give the following important information ... 

Properties of toxins. Dinophysistoxin-1 was isolated as a white amorphous solid m.p. 134 C ] +28 (c 0.046, chloroform) Rf in TLC 0.42 minimum lethal dose to mouse 160 ig/kg (i.p.). El mass spectrum gave a dehydrated ion peak at m/z 800, pointing to a composition C45H5gOi2 Overall features of both PMR and CMR spectra of dinophys is toxin-1 closely resembled those of okadaic acid (I ) except the presence of an additional methyl in dinophysistoxin-1. Comparison of the spectra of okadaic acid and dinophysistoxin-1 and supplemental spin-spin decoupling measurements enabled us to assign dinophysistoxin-1 to 35(5)-methyl okadaic acid (II) (5). A component tentatively named dinophysistoxin-2 was slightly more polar than dinophysistoxin-1 but its characterization was unsuccessful due to the extreme smallness of the sample size. 

Comparison of the 13C NMR spectrum of commercial polyvinyl chloride with the CMR spectra of racem- and meso-2,4-dichloropentane permits signal identification of the syndiotactic, heterotactic and isotactic methine carbons of the polymer [262]. 

Noise and single frequency off-resonance decoupled CMR spectra of disopyramide phosphate in deuterated water solution are shown in Figures 4 and 5.2 Shifts are reported in ppm downfield from the shift of tetramethyl silane as referenced to a shift of 67.4 ppm for dioxane which was used as an internal reference. 

The remaining chemical shifts of gelsemine are deduced by comparison with simple models and, where ambiguities remain, by comparison with the CMR spectra of a dihydro and tetrahydro derivative taking advantage of the environmental dissimilarity of some of their carbon centers. Thus saturation of the vinyl group would be expected to affect... 

That pandine contained a tertiary alcohol was evident from the shift of a quaternary carbon from 80.3 to 90.4 ppm upon acetylation and from the dehydration product which showed an ethylidene group. The location of the additional C-C bond was determined by analysis of the PMR and CMR spectra. 

Isol. from exopolysaccharides of the blue-green alga Cyanospira capsulata. Both epimers have been synthesised but the cmr spectra were too similar to allow assignment of config. to the nat. prod. 

Fig. 7. Cmr spectra of the polymerization system ([PO]0/[Cat]o=5) and oligomer obtained by TPPH2-Et2AICI system.

The PMR spectra of several reduced proaporphines have been recorded both in deuteriochloroform and in pyridine-dg. PMR chemical shifts for 8,9-dihydroglaziovine in deuteriochloroform are shown below. The CMR spectra of fifteen reduced proaporphines have been recorded. 

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