The structure of roemrefine
ConclusionsStructure (1) has been established for roemrefine on the basis of a study of the products of its Hofmann degradation, oxidation, and spectral characteristics.
Structure of the sequiterpene lactones fromCyclachaena xanthifolia
ConclusionsThe racemes ofCyclachaena xanthifolia Fresen. have yielded four sesquiterpene lactones, two of which are new, not having been described in the literature previously, and these have been called ivoxanthin and 1,2-anhydrocoronopilin. Structures II and IV have been proposed for these.The plant also contains the sesquiterpene lactones coronopilin and ambrosin.
ASSIGNMENT OF THE N-METHYL HYDROGEN NMR PEAKS OF CAFFEINE.
The NMR spectrum of caffeine exhibits a separate peak for each of the three N -methyl groups. Assignment of each peak to a specific N -methyl group was made by comparison of the spectrum of caffeine with those of two caffeine homologs, in each of which one of the N -methyl groups is replaced with an N -ethyl group.