Six new diterpenic acids with a rearranged ent-labdane skeleton have b
een isolated from the aerial parts of Halimium viscosum (Villarino de
los Aires chemotype) and separated in methyl ester form. These diterpe
nes were the formate, propionate, Z-cinnamate and cinnamate of 15-hydr
oxy-1(10), 13E-ent-halimadien-18-acid, and 13R and 13S-hydroxy-1(10),1
4-ent-halimadien-18-oic acids.