Triptohypol NOESY spectrum

Triptohypol F (18) showed the presence of one double bond, two methine carbons attached to an oxygen function and one methoxy group, according to the 13C NMR spectrum. From these data and its H NMR and MS spectra, it was assumed to be an oleanane-type triterpene. The location of the double bond and the hydroxyl and methoxy groups were determined by a HMBC experiment. The stereochemistry of the hydroxyl and methoxy groups were determined by a NOESY spectrum. According to these data the structure of (18) was established as showed above. 

The study of the outer root bark of T. hypoglaucum collected in China afforded three new structures of phenolic triterpenes. Duan et al. isolated triptohypol A (80), B (81) and C (82), a series of new phenolic compounds related to celastrol [29]. Triptohypol A (80) was isolated as an amorphous powder and spectroscopic means and chemical modification determined its structure. By HREIMS the formula C30H40O6 was determined, and H-NMR spectrum showed five methyl signals, a methoxy moiety, a methylene attached to an oxygen atom and two vinyl protons. Data from 13C-NMR experiments indicated the presence of a pair of carbonyl groups and was quite similar to that of wilforol A (78). The analysis of HMQC and HMBC experiments allowed to establish the structure for rings A and B, based on the correlations observed between the proton H-l (8 6.95 ppm) and the carbons C-3, C-5 and C-10. Finally, the position of the carbonyl group was established at C-6 based on a NOESY experiment of the dimethyl derivative. 

Triptohypol B (81) evidenced a very similar 13C-NMR spectrum when compared to triptohypol A, except for the replacement of a methylene carbon by a methyl carbon, which was supported by the formula CsoHLioOs, determined by HREIMS. A NOESY experiment indicated the correlation between the methyl proton signal with that of the C-3 methoxy group, which allowed to establish the structure of triptohypol B (81). 

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See also in sourсe #XX -- [ , , ]

See also in sourсe #XX -- [ , ]

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