On the structures of the diterpenes licamichauxiioic acids A and B.
The structures of the diterpenes licamichauxiioic acids A and B, isolated from Licania michauxii, which had been reported as 15-oxo-ent-kaur-9(11),16-dien-19-oic acid (1) and 15-oxo-ent-kaur-13,16-dien-19-oic acid (3), respectively, are not correct. Starting from grandiflorenic acid (6) we had prepared a compound with the proposed structure for licamichauxiioic acid A, and its spectroscopic data are different from those given for this acid. In the case of licamichauxiioic acid B, its NMR data are not in accordance with the proposed structure 3, which also violates Bredt's rule. In addition, we described a useful method for the separation of grandiflorenic and grandiflorolic acids.
Fraga
Braulio M
BM
Instituto de Productos Naturales y Agrobiología, CSIC, Avenida Astrofisico F. Sánchez 3, 38206-La Laguna, Tenerife, Canary Islands, Spain. bmfraga@ipna.csic.es
Cabrera
Inmaculada
I
Amaro-Luis
Juan M
JM
D004224:Diterpenes / Q000737:chemistry*; D015394:Molecular Structure; D018517:Plant Roots / Q000737:chemistry
D004224:Diterpenes; C528608:grandiflorolic acid; C456093:licamichauxiioic-A acid; C456092:licamichauxiioic-B acid; C014576:grandiflorenic acid