ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Leaf-gland Pigments: Coleons U, V, W, 14-O-Formyl-coleon-V, and two Royleanones from Plectranthus myrianthus BRIQ.; cis- and trans-A/B-6,7-DioxoroyleanonesFrom leaf-glands of the South-African P. myrianthus (Labiatae) the following diterpenoids have been isolated and their structures established: coleon U, C20H26O5 (6, 11, 12, 14-tetrahydroxy-abieta-5, 8, 11, 13-tetraene-7-one, 2a); coleon V, C20H26O5 (11, 12, 14-trihydroxy-abieta-8, 11, 13-triene-6, 7-dione, 4a); coleon W, C22H28O8 (16(or 17)-acetoxy-6, 11, 12, 14, 17 (or 16)-pentahydroxy-abieta-5, 8, 11, 13-tetraene-7-one, 6); 14-O-formyl-coleon-V, C21H26O6 (14-formyloxy-11, 12-dihydroxy-abieta-8, 11, 13-triene-6, 7-dione, 4b); 7α-formyloxy-6β-hydroxyroyleanone, C21H28O6 (7α-formyloxy-6β, 12-dihydroxy-abieta-8, 12-diene-11, 14-dione, 1a); the already known 6β, 7α-dihydroxyroyleanone (1c) and a dimeric abietane derivative whose structure is not yet elucidated. This is the first record of a co-occurrence of coleons and royleanones in the same plant. In the course of chemical investigations of 4a and 4b the highly oxidized trans- and cis-A/B-6,7-dioxoroyleanones (5a and 5b) were obtained.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19770600830
