Canna~Fangled Abstracts

NMR assignments of the major cannabinoids and cannabiflavonoids isolated from flowers of Cannabis sativa.

By September 5, 2013No Comments

pm2NMR assignments of the major cannabinoids and cannabiflavonoids isolated from flowers of Cannabis sativa.

Source

Division of Pharmacognosy, Section Metabolomics, Institute of Biology, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands.

Abstract

The complete 1H- and 13C-NMR assignments of the major Cannabis constituents, delta9-tetrahydrocannabinol, tetrahydrocannabinolic acid, delta8-tetrahydrocannabinol, cannabigerol, cannabinol, cannabidiol, cannabidiolic acid, cannflavin A and cannflavin B have been determined on the basis of one- and two-dimensional NMR spectra including 1H- and 13C-NMR, 1H-1H-COSY, HMQC and HMBC. The substitution of carboxylic acid on the cannabinoid nucleus (as in tetrahydrocannabinolic acid and cannabidiolic acid) has a large effect on the chemical shift of H-1″ of the C5 side chain and 2′-OH. It was also observed that carboxylic acid substitution reduces intermolecular hydrogen bonding resulting in a sharpening of the H-5′ signal in cannabinolic acid in deuterated chloroform. The additional aromaticity of cannabinol causes the two angular methyl groups (H-8 and H-9) to show identical 1H-NMR shifts, which indicates that the two aromatic rings are in one plane in contrast to the other cannabinoids. For the cannabiflavonoids, the unambiguous assignments of C-3′ and C-4′ of cannflavin A and B were determined by HMBC spectra.
PMID:

 

15595449

 

[PubMed – indexed for MEDLINE]
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