Assertion: alkaloid's structure | /r/HasProperty | established
Facets:
value: by comparing theirh
type: MANNER
value: firmly
type: MANNER
Source sentences:
text: The gross structure was deduced from spectral and chemical evidence but the stereochemistry of the skytanthine units in 54 remains to be firmly established .
text: The structures of these known alkaloids were established by comparing theirH,C-NMR, and mass spectral data with literature values [ 16 19 ].
text: Thus, the planar structure of compound 2 was established.